Grob 103 Twin II Brake Master Cylinder

[Mike McCarron]

My club has a 1983 Grob 103 Twin II that needs a new master cylinder. Over
the years the Grob factory has made changes to the system without full
documentation and as a result the US distributor can not be sure of how I
go about purchasing the proper master cylinder for this glider.

If you or anyone you know has replaced the master cylinder on a vintage
Grob 103 Twin II recently I would appreciate your input on where I might
purchase the correct system.

Thank you,

Mike

[JJ Sinclair]

If memory serves me, its a motorcycle master cylinder BMW? I believe
they cut it down from the original, good luck getting your inspector
to sign off on installing it!
JJ

Mike McCarron wrote:
> My club has a 1983 Grob 103 Twin II that needs a new master cylinder. Over
> the years the Grob factory has made changes to the system without full
> documentation and as a result the US distributor can not be sure of how I
> go about purchasing the proper master cylinder for this glider.
>
> If you or anyone you know has replaced the master cylinder on a vintage
> Grob 103 Twin II recently I would appreciate your input on where I might
> purchase the correct system.
>
> Thank you,
>
> Mike

[Mike McCarron[_2_]]

JJ,

I did purchase a master cylinder from a BMW motorcycle dealer that did fit
in place. Unfortunately it did not function properly. It was properly
bled and all but it did not work. I don't know what to do next. There
must be at least 100 of these gliders in the US that will need a master
cylinder replacement in the future. I don't see how we can junk a $30K
glider for lack of a functioning master cylinder.

Thanks for your comment,

MC

At 13:41 22 October 2008, JJ Sinclair wrote:
>If memory serves me, its a motorcycle master cylinder BMW? I believe
>they cut it down from the original, good luck getting your inspector
>to sign off on installing it!
>JJ
>
>Mike McCarron wrote:
>> My club has a 1983 Grob 103 Twin II that needs a new master cylinder.
>Over
>> the years the Grob factory has made changes to the system without full
>> documentation and as a result the US distributor can not be sure of
how
>I
>> go about purchasing the proper master cylinder for this glider.
>>
>> If you or anyone you know has replaced the master cylinder on a
vintage
>> Grob 103 Twin II recently I would appreciate your input on where I
might
>> purchase the correct system.
>>
>> Thank you,
>>
>> Mike
>

[JJ Sinclair]

Why didn't it work, Mike? Hydraulics are hydraulics, the Clevland
brake slave cylinder doesn't know (or care) where that pressure is
coming from? Make sure you have compatible seals. What type fluid does
BMW use? Can't mix the red stuff with the clear stuff.
JJ

Mike McCarron wrote:
> JJ,
>
> I did purchase a master cylinder from a BMW motorcycle dealer that did fit
> in place. Unfortunately it did not function properly. It was properly
> bled and all but it did not work. I don't know what to do next. There
> must be at least 100 of these gliders in the US that will need a master
> cylinder replacement in the future. I don't see how we can junk a $30K
> glider for lack of a functioning master cylinder.
>
> Thanks for your comment,
>
> MC
>
> At 13:41 22 October 2008, JJ Sinclair wrote:
> >If memory serves me, its a motorcycle master cylinder BMW? I believe
> >they cut it down from the original, good luck getting your inspector
> >to sign off on installing it!
> >JJ
> >
> >Mike McCarron wrote:
> >> My club has a 1983 Grob 103 Twin II that needs a new master cylinder.
> >Over
> >> the years the Grob factory has made changes to the system without full
> >> documentation and as a result the US distributor can not be sure of
> how
> >I
> >> go about purchasing the proper master cylinder for this glider.
> >>
> >> If you or anyone you know has replaced the master cylinder on a
> vintage
> >> Grob 103 Twin II recently I would appreciate your input on where I
> might
> >> purchase the correct system.
> >>
> >> Thank you,
> >>
> >> Mike
> >

[Mike McCarron[_2_]]

JJ,

I used Dot 3 fluid with compatible O ring on the slave cylinder. The cap
on the BMW master cylinder said to use DOT 3/4 brake fluid only.

MC

At 14:22 22 October 2008, JJ Sinclair wrote:
>Why didn't it work, Mike? Hydraulics are hydraulics, the Clevland
>brake slave cylinder doesn't know (or care) where that pressure is
>coming from? Make sure you have compatible seals. What type fluid does
>BMW use? Can't mix the red stuff with the clear stuff.
>JJ
>
>Mike McCarron wrote:
>> JJ,
>>
>> I did purchase a master cylinder from a BMW motorcycle dealer that did
>fit
>> in place. Unfortunately it did not function properly. It was
properly
>> bled and all but it did not work. I don't know what to do next.
There
>> must be at least 100 of these gliders in the US that will need a
master
>> cylinder replacement in the future. I don't see how we can junk a
$30K
>> glider for lack of a functioning master cylinder.
>>
>> Thanks for your comment,
>>
>> MC
>>
>> At 13:41 22 October 2008, JJ Sinclair wrote:
>> >If memory serves me, its a motorcycle master cylinder BMW? I believe
>> >they cut it down from the original, good luck getting your inspector
>> >to sign off on installing it!
>> >JJ
>> >
>> >Mike McCarron wrote:
>> >> My club has a 1983 Grob 103 Twin II that needs a new master
cylinder.
>> >Over
>> >> the years the Grob factory has made changes to the system without
>full
>> >> documentation and as a result the US distributor can not be sure of
>> how
>> >I
>> >> go about purchasing the proper master cylinder for this glider.
>> >>
>> >> If you or anyone you know has replaced the master cylinder on a
>> vintage
>> >> Grob 103 Twin II recently I would appreciate your input on where I
>> might
>> >> purchase the correct system.
>> >>
>> >> Thank you,
>> >>
>> >> Mike
>> >
>

[bumper]

Yup, what JJ said. The "red stuff" is Mil Spec 5606 hydraulic oil and is
compatible with Buna-N O-rings and seals. It's also commonly used in the USA
for most small GA aircraft.

DOT automotive brake fluid, the "clear stuff", most often glycol-ether
based, and is compatible with EPDM rubber seals.

If you are switching parts from one fluid to the other, you gotta change the
rubber stuff.

bumper


"JJ Sinclair" > wrote in message
...
> Why didn't it work, Mike? Hydraulics are hydraulics, the Clevland
> brake slave cylinder doesn't know (or care) where that pressure is
> coming from? Make sure you have compatible seals. What type fluid does
> BMW use? Can't mix the red stuff with the clear stuff.
> JJ
>
> Mike McCarron wrote:
>> JJ,
>>
>> I did purchase a master cylinder from a BMW motorcycle dealer that did
>> fit
>> in place. Unfortunately it did not function properly. It was properly
>> bled and all but it did not work. I don't know what to do next. There
>> must be at least 100 of these gliders in the US that will need a master
>> cylinder replacement in the future. I don't see how we can junk a $30K
>> glider for lack of a functioning master cylinder.
>>
>> Thanks for your comment,
>>
>> MC
>>
>> At 13:41 22 October 2008, JJ Sinclair wrote:
>> >If memory serves me, its a motorcycle master cylinder BMW? I believe
>> >they cut it down from the original, good luck getting your inspector
>> >to sign off on installing it!
>> >JJ
>> >
>> >Mike McCarron wrote:
>> >> My club has a 1983 Grob 103 Twin II that needs a new master cylinder.
>> >Over
>> >> the years the Grob factory has made changes to the system without full
>> >> documentation and as a result the US distributor can not be sure of
>> how
>> >I
>> >> go about purchasing the proper master cylinder for this glider.
>> >>
>> >> If you or anyone you know has replaced the master cylinder on a
>> vintage
>> >> Grob 103 Twin II recently I would appreciate your input on where I
>> might
>> >> purchase the correct system.
>> >>
>> >> Thank you,
>> >>
>> >> Mike
>> >

[Uncle Fuzzy]

On Oct 22, 8:01*am, "bumper" > wrote:
> Yup, what JJ said. The "red stuff" is Mil Spec 5606 hydraulic oil and is
> compatible with Buna-N O-rings and seals. It's also commonly used in the USA
> for most small GA aircraft.
>
> DOT automotive brake fluid, the "clear stuff", most often glycol-ether
> based, and is compatible with EPDM rubber seals.
>
> If you are switching parts from one fluid to the other, you gotta change the
> rubber stuff.
>
> bumper
>
> "JJ Sinclair" > wrote in message
>
> ...
>
>
>
> > Why didn't it work, Mike? Hydraulics are hydraulics, the Clevland
> > brake slave cylinder doesn't know (or care) where that pressure is
> > coming from? Make sure you have compatible seals. What type fluid does
> > BMW use? Can't mix the red stuff with the clear stuff.
> > JJ
>
> > Mike McCarron wrote:
> >> JJ,
>
> >> I did purchase a master cylinder from a BMW motorcycle dealer that did
> >> fit
> >> in place. *Unfortunately it did not function properly. *It was properly
> >> bled and all but it did not work. *I don't know what to do next. *There
> >> must be at least 100 of these gliders in the US that will need a master
> >> cylinder replacement in the future. *I don't see how we can junk a $30K
> >> glider for lack of a functioning master cylinder.
>
> >> Thanks for your comment,
>
> >> MC
>
> >> At 13:41 22 October 2008, JJ Sinclair wrote:
> >> >If memory serves me, its a motorcycle master cylinder BMW? I believe
> >> >they cut it down from the original, good luck getting your inspector
> >> >to sign off on installing it!
> >> >JJ
>
> >> >Mike McCarron wrote:
> >> >> My club has a 1983 Grob 103 Twin II that needs a new master cylinder.

[Uncle Fuzzy]

On Oct 22, 8:22*am, Uncle Fuzzy > wrote:
> On Oct 22, 8:01*am, "bumper" > wrote:
>
>
>
>
>
> > Yup, what JJ said. The "red stuff" is Mil Spec 5606 hydraulic oil and is
> > compatible with Buna-N O-rings and seals. It's also commonly used in the USA
> > for most small GA aircraft.
>
> > DOT automotive brake fluid, the "clear stuff", most often glycol-ether
> > based, and is compatible with EPDM rubber seals.
>
> > If you are switching parts from one fluid to the other, you gotta change the
> > rubber stuff.
>
> > bumper
>
> > "JJ Sinclair" > wrote in message
>
> ....
>
> > > Why didn't it work, Mike? Hydraulics are hydraulics, the Clevland
> > > brake slave cylinder doesn't know (or care) where that pressure is
> > > coming from? Make sure you have compatible seals. What type fluid does
> > > BMW use? Can't mix the red stuff with the clear stuff.
> > > JJ
>
> > > Mike McCarron wrote:
> > >> JJ,
>
> > >> I did purchase a master cylinder from a BMW motorcycle dealer that did
> > >> fit
> > >> in place. *Unfortunately it did not function properly. *It was properly
> > >> bled and all but it did not work. *I don't know what to do next. *There
> > >> must be at least 100 of these gliders in the US that will need a master
> > >> cylinder replacement in the future. *I don't see how we can junk a $30K
> > >> glider for lack of a functioning master cylinder.
>
> > >> Thanks for your comment,
>
> > >> MC
>
> > >> At 13:41 22 October 2008, JJ Sinclair wrote:
> > >> >If memory serves me, its a motorcycle master cylinder BMW? I believe
> > >> >they cut it down from the original, good luck getting your inspector
> > >> >to sign off on installing it!
> > >> >JJ
>
> > >> >Mike McCarron wrote:
> > >> >> My club has a 1983 Grob 103 Twin II that needs a new master cylinder.
> > >> >Over
> > >> >> the years the Grob factory has made changes to the system without full
> > >> >> documentation and as a result the US distributor can not be sure of
> > >> how
> > >> >I
> > >> >> go about purchasing the proper master cylinder for this glider.
>
> > >> >> If you or anyone you know has replaced the master cylinder on a
> > >> vintage
> > >> >> Grob 103 Twin II recently I would appreciate your input on where I
> > >> might
> > >> >> purchase the correct system.
>
> > >> >> Thank you,
>
> > >> >> Mike- Hide quoted text -
>
> > - Show quoted text -
>
> In our club Grob 103, the master cylinder is a Magura motorcycle front
> brake master cylinder. *Magura makes parts for a bunch of bikes, and
> for the aftermarket. Motorcycle front brake master cylinders come in a
> variety of piston diameters. *They are also somewhat weird to bleed.
> They won't develop pressure unless almost all of the air is bled out
> of the system. *"Pumping" one endlessly has no effect. *On a bike, one
> trick is to zip tie the handle so that the lever is halfway to the
> grip, crack the bleeder on the caliper (with a tube on it to direct
> the drainage), and walk away for a couple hours and let gravity do
> some work for you. *Much quicker is to zip tie the lever halfway, and
> use a small vacuum pump rig to PULL the fluid through. *Once most of
> the air is gone, you should be able to develop some pressure to
> complete the bleeding in the normal manner. *YES to DOT 3/4. *NO to
> Mil Spec 5606 hydraulic oil. *As an experiment, I tossed some
> motorcycle brake bits in a jar of 5606. *They turned into something
> other than brake bits pretty quickly.- Hide quoted text -
>
> - Show quoted text -

Clarification on the quicker way to purge the air out: Zip tie the
lever at half travel, use a vacuum pump ON THE CALIPER BLEEDER to pull
brake fluid through. Hope this helps

[Mike McCarron[_2_]]

How can one tell where to position the lever? Half way through it's total
travel or some other location?

MC

At 16:33 22 October 2008, Uncle Fuzzy wrote:
>On Oct 22, 8:22=A0am, Uncle Fuzzy wrote:
>> On Oct 22, 8:01=A0am, "bumper" wrote:
>>
>>
>>
>>
>>
>> > Yup, what JJ said. The "red stuff" is Mil Spec 5606 hydraulic oil
and
>i=
>s
>> > compatible with Buna-N O-rings and seals. It's also commonly used
in
>th=
>e USA
>> > for most small GA aircraft.
>>
>> > DOT automotive brake fluid, the "clear stuff", most often
glycol-ether
>> > based, and is compatible with EPDM rubber seals.
>>
>> > If you are switching parts from one fluid to the other, you gotta
>chang=
>e the
>> > rubber stuff.
>>
>> > bumper
>>
>> > "JJ Sinclair" wrote in message
>>
>>
..=
>..
>>
>> > > Why didn't it work, Mike? Hydraulics are hydraulics, the Clevland
>> > > brake slave cylinder doesn't know (or care) where that pressure
is
>> > > coming from? Make sure you have compatible seals. What type fluid
>doe=
>s
>> > > BMW use? Can't mix the red stuff with the clear stuff.
>> > > JJ
>>
>> > > Mike McCarron wrote:
>> > >> JJ,
>>
>> > >> I did purchase a master cylinder from a BMW motorcycle dealer
that
>d=
>id
>> > >> fit
>> > >> in place. =A0Unfortunately it did not function properly. =A0It
was
>p=
>roperly
>> > >> bled and all but it did not work. =A0I don't know what to do
next.
>=
>=A0There
>> > >> must be at least 100 of these gliders in the US that will need a
>mas=
>ter
>> > >> cylinder replacement in the future. =A0I don't see how we can
junk
>a=
> $30K
>> > >> glider for lack of a functioning master cylinder.
>>
>> > >> Thanks for your comment,
>>
>> > >> MC
>>
>> > >> At 13:41 22 October 2008, JJ Sinclair wrote:
>> > >> >If memory serves me, its a motorcycle master cylinder BMW? I
>believ=
>e
>> > >> >they cut it down from the original, good luck getting your
>inspecto=
>r
>> > >> >to sign off on installing it!
>> > >> >JJ
>>
>> > >> >Mike McCarron wrote:
>> > >> >> My club has a 1983 Grob 103 Twin II that needs a new master
>cylin=
>der.
>> > >> >Over
>> > >> >> the years the Grob factory has made changes to the system
>without=
> full
>> > >> >> documentation and as a result the US distributor can not be
sure
>=
>of
>> > >> how
>> > >> >I
>> > >> >> go about purchasing the proper master cylinder for this
glider.
>>
>> > >> >> If you or anyone you know has replaced the master cylinder on
a
>> > >> vintage
>> > >> >> Grob 103 Twin II recently I would appreciate your input on
where
>=
>I
>> > >> might
>> > >> >> purchase the correct system.
>>
>> > >> >> Thank you,
>>
>> > >> >> Mike- Hide quoted text -
>>
>> > - Show quoted text -
>>
>> In our club Grob 103, the master cylinder is a Magura motorcycle front
>> brake master cylinder. =A0Magura makes parts for a bunch of bikes, and
>> for the aftermarket. Motorcycle front brake master cylinders come in a
>> variety of piston diameters. =A0They are also somewhat weird to bleed.
>> They won't develop pressure unless almost all of the air is bled out
>> of the system. =A0"Pumping" one endlessly has no effect. =A0On a
bike,
>on=
>e
>> trick is to zip tie the handle so that the lever is halfway to the
>> grip, crack the bleeder on the caliper (with a tube on it to direct
>> the drainage), and walk away for a couple hours and let gravity do
>> some work for you. =A0Much quicker is to zip tie the lever halfway,
and
>> use a small vacuum pump rig to PULL the fluid through. =A0Once most of
>> the air is gone, you should be able to develop some pressure to
>> complete the bleeding in the normal manner. =A0YES to DOT 3/4. =A0NO
to
>> Mil Spec 5606 hydraulic oil. =A0As an experiment, I tossed some
>> motorcycle brake bits in a jar of 5606. =A0They turned into something
>> other than brake bits pretty quickly.- Hide quoted text -
>>
>> - Show quoted text -
>
>Clarification on the quicker way to purge the air out: Zip tie the
>lever at half travel, use a vacuum pump ON THE CALIPER BLEEDER to pull
>brake fluid through. Hope this helps
>

[bumper]

Hook up vacuum pot to caliper bleed valve, open valve a turn, apply vacuum,
squeeze lever slowly until fluid flows out of bleed valve. Be sure to add
fluid to reservoir as level drops.

bumper

"Mike McCarron" > wrote in message
...
> How can one tell where to position the lever? Half way through it's total
> travel or some other location?
>
> MC
>
> At 16:33 22 October 2008, Uncle Fuzzy wrote:
>>On Oct 22, 8:22=A0am, Uncle Fuzzy wrote:
>>> On Oct 22, 8:01=A0am, "bumper" wrote:
>>>
>>>
>>>
>>>
>>>
>>> > Yup, what JJ said. The "red stuff" is Mil Spec 5606 hydraulic oil
> and
>>i=
>>s
>>> > compatible with Buna-N O-rings and seals. It's also commonly used
> in
>>th=
>>e USA
>>> > for most small GA aircraft.
>>>
>>> > DOT automotive brake fluid, the "clear stuff", most often
> glycol-ether
>>> > based, and is compatible with EPDM rubber seals.
>>>
>>> > If you are switching parts from one fluid to the other, you gotta
>>chang=
>>e the
>>> > rubber stuff.
>>>
>>> > bumper
>>>
>>> > "JJ Sinclair" wrote in message
>>>
>>>
..=
>>..
>>>
>>> > > Why didn't it work, Mike? Hydraulics are hydraulics, the Clevland
>>> > > brake slave cylinder doesn't know (or care) where that pressure
> is
>>> > > coming from? Make sure you have compatible seals. What type fluid
>>doe=
>>s
>>> > > BMW use? Can't mix the red stuff with the clear stuff.
>>> > > JJ
>>>
>>> > > Mike McCarron wrote:
>>> > >> JJ,
>>>
>>> > >> I did purchase a master cylinder from a BMW motorcycle dealer
> that
>>d=
>>id
>>> > >> fit
>>> > >> in place. =A0Unfortunately it did not function properly. =A0It
> was
>>p=
>>roperly
>>> > >> bled and all but it did not work. =A0I don't know what to do
> next.
>>=
>>=A0There
>>> > >> must be at least 100 of these gliders in the US that will need a
>>mas=
>>ter
>>> > >> cylinder replacement in the future. =A0I don't see how we can
> junk
>>a=
>> $30K
>>> > >> glider for lack of a functioning master cylinder.
>>>
>>> > >> Thanks for your comment,
>>>
>>> > >> MC
>>>
>>> > >> At 13:41 22 October 2008, JJ Sinclair wrote:
>>> > >> >If memory serves me, its a motorcycle master cylinder BMW? I
>>believ=
>>e
>>> > >> >they cut it down from the original, good luck getting your
>>inspecto=
>>r
>>> > >> >to sign off on installing it!
>>> > >> >JJ
>>>
>>> > >> >Mike McCarron wrote:
>>> > >> >> My club has a 1983 Grob 103 Twin II that needs a new master
>>cylin=
>>der.
>>> > >> >Over
>>> > >> >> the years the Grob factory has made changes to the system
>>without=
>> full
>>> > >> >> documentation and as a result the US distributor can not be
> sure
>>=
>>of
>>> > >> how
>>> > >> >I
>>> > >> >> go about purchasing the proper master cylinder for this
> glider.
>>>
>>> > >> >> If you or anyone you know has replaced the master cylinder on
> a
>>> > >> vintage
>>> > >> >> Grob 103 Twin II recently I would appreciate your input on
> where
>>=
>>I
>>> > >> might
>>> > >> >> purchase the correct system.
>>>
>>> > >> >> Thank you,
>>>
>>> > >> >> Mike- Hide quoted text -
>>>
>>> > - Show quoted text -
>>>
>>> In our club Grob 103, the master cylinder is a Magura motorcycle front
>>> brake master cylinder. =A0Magura makes parts for a bunch of bikes, and
>>> for the aftermarket. Motorcycle front brake master cylinders come in a
>>> variety of piston diameters. =A0They are also somewhat weird to bleed.
>>> They won't develop pressure unless almost all of the air is bled out
>>> of the system. =A0"Pumping" one endlessly has no effect. =A0On a
> bike,
>>on=
>>e
>>> trick is to zip tie the handle so that the lever is halfway to the
>>> grip, crack the bleeder on the caliper (with a tube on it to direct
>>> the drainage), and walk away for a couple hours and let gravity do
>>> some work for you. =A0Much quicker is to zip tie the lever halfway,
> and
>>> use a small vacuum pump rig to PULL the fluid through. =A0Once most of
>>> the air is gone, you should be able to develop some pressure to
>>> complete the bleeding in the normal manner. =A0YES to DOT 3/4. =A0NO
> to
>>> Mil Spec 5606 hydraulic oil. =A0As an experiment, I tossed some
>>> motorcycle brake bits in a jar of 5606. =A0They turned into something
>>> other than brake bits pretty quickly.- Hide quoted text -
>>>
>>> - Show quoted text -
>>
>>Clarification on the quicker way to purge the air out: Zip tie the
>>lever at half travel, use a vacuum pump ON THE CALIPER BLEEDER to pull
>>brake fluid through. Hope this helps
>>

[JJ Sinclair]

The only way I ever got a Grob brake to bleed properly was to use a
pressure bleeder where fluid is forced up through the system from the
slave cylinder. Not too expensive from Spruce & Specialty.
JJ

Mike McCarron wrote:
> JJ,
>
> I used Dot 3 fluid with compatible O ring on the slave cylinder. The cap
> on the BMW master cylinder said to use DOT 3/4 brake fluid only.
>
> MC
>
> At 14:22 22 October 2008, JJ Sinclair wrote:
> >Why didn't it work, Mike? Hydraulics are hydraulics, the Clevland
> >brake slave cylinder doesn't know (or care) where that pressure is
> >coming from? Make sure you have compatible seals. What type fluid does
> >BMW use? Can't mix the red stuff with the clear stuff.
> >JJ
> >
> >Mike McCarron wrote:
> >> JJ,
> >>
> >> I did purchase a master cylinder from a BMW motorcycle dealer that did
> >fit
> >> in place. Unfortunately it did not function properly. It was
> properly
> >> bled and all but it did not work. I don't know what to do next.
> There
> >> must be at least 100 of these gliders in the US that will need a
> master
> >> cylinder replacement in the future. I don't see how we can junk a
> $30K
> >> glider for lack of a functioning master cylinder.
> >>
> >> Thanks for your comment,
> >>
> >> MC
> >>
> >> At 13:41 22 October 2008, JJ Sinclair wrote:
> >> >If memory serves me, its a motorcycle master cylinder BMW? I believe
> >> >they cut it down from the original, good luck getting your inspector
> >> >to sign off on installing it!
> >> >JJ
> >> >
> >> >Mike McCarron wrote:
> >> >> My club has a 1983 Grob 103 Twin II that needs a new master
> cylinder.
> >> >Over
> >> >> the years the Grob factory has made changes to the system without
> >full
> >> >> documentation and as a result the US distributor can not be sure of
> >> how
> >> >I
> >> >> go about purchasing the proper master cylinder for this glider.
> >> >>
> >> >> If you or anyone you know has replaced the master cylinder on a
> >> vintage
> >> >> Grob 103 Twin II recently I would appreciate your input on where I
> >> might
> >> >> purchase the correct system.
> >> >>
> >> >> Thank you,
> >> >>
> >> >> Mike
> >> >
> >

[Tim Mara[_2_]]

there is now a new bleeder system from TOST
for details please see http://www.wingsandwheels.com/page32.htm
tim
Please visit the Wings & Wheels website at www.wingsandwheels.com

"Mike McCarron" > wrote in message
...
> How can one tell where to position the lever? Half way through it's total
> travel or some other location?
>
> MC
>
> At 16:33 22 October 2008, Uncle Fuzzy wrote:
>>On Oct 22, 8:22=A0am, Uncle Fuzzy wrote:
>>> On Oct 22, 8:01=A0am, "bumper" wrote:
>>>
>>>
>>>
>>>
>>>
>>> > Yup, what JJ said. The "red stuff" is Mil Spec 5606 hydraulic oil
> and
>>i=
>>s
>>> > compatible with Buna-N O-rings and seals. It's also commonly used
> in
>>th=
>>e USA
>>> > for most small GA aircraft.
>>>
>>> > DOT automotive brake fluid, the "clear stuff", most often
> glycol-ether
>>> > based, and is compatible with EPDM rubber seals.
>>>
>>> > If you are switching parts from one fluid to the other, you gotta
>>chang=
>>e the
>>> > rubber stuff.
>>>
>>> > bumper
>>>
>>> > "JJ Sinclair" wrote in message
>>>
>>>
..=
>>..
>>>
>>> > > Why didn't it work, Mike? Hydraulics are hydraulics, the Clevland
>>> > > brake slave cylinder doesn't know (or care) where that pressure
> is
>>> > > coming from? Make sure you have compatible seals. What type fluid
>>doe=
>>s
>>> > > BMW use? Can't mix the red stuff with the clear stuff.
>>> > > JJ
>>>
>>> > > Mike McCarron wrote:
>>> > >> JJ,
>>>
>>> > >> I did purchase a master cylinder from a BMW motorcycle dealer
> that
>>d=
>>id
>>> > >> fit
>>> > >> in place. =A0Unfortunately it did not function properly. =A0It
> was
>>p=
>>roperly
>>> > >> bled and all but it did not work. =A0I don't know what to do
> next.
>>=
>>=A0There
>>> > >> must be at least 100 of these gliders in the US that will need a
>>mas=
>>ter
>>> > >> cylinder replacement in the future. =A0I don't see how we can
> junk
>>a=
>> $30K
>>> > >> glider for lack of a functioning master cylinder.
>>>
>>> > >> Thanks for your comment,
>>>
>>> > >> MC
>>>
>>> > >> At 13:41 22 October 2008, JJ Sinclair wrote:
>>> > >> >If memory serves me, its a motorcycle master cylinder BMW? I
>>believ=
>>e
>>> > >> >they cut it down from the original, good luck getting your
>>inspecto=
>>r
>>> > >> >to sign off on installing it!
>>> > >> >JJ
>>>
>>> > >> >Mike McCarron wrote:
>>> > >> >> My club has a 1983 Grob 103 Twin II that needs a new master
>>cylin=
>>der.
>>> > >> >Over
>>> > >> >> the years the Grob factory has made changes to the system
>>without=
>> full
>>> > >> >> documentation and as a result the US distributor can not be
> sure
>>=
>>of
>>> > >> how
>>> > >> >I
>>> > >> >> go about purchasing the proper master cylinder for this
> glider.
>>>
>>> > >> >> If you or anyone you know has replaced the master cylinder on
> a
>>> > >> vintage
>>> > >> >> Grob 103 Twin II recently I would appreciate your input on
> where
>>=
>>I
>>> > >> might
>>> > >> >> purchase the correct system.
>>>
>>> > >> >> Thank you,
>>>
>>> > >> >> Mike- Hide quoted text -
>>>
>>> > - Show quoted text -
>>>
>>> In our club Grob 103, the master cylinder is a Magura motorcycle front
>>> brake master cylinder. =A0Magura makes parts for a bunch of bikes, and
>>> for the aftermarket. Motorcycle front brake master cylinders come in a
>>> variety of piston diameters. =A0They are also somewhat weird to bleed.
>>> They won't develop pressure unless almost all of the air is bled out
>>> of the system. =A0"Pumping" one endlessly has no effect. =A0On a
> bike,
>>on=
>>e
>>> trick is to zip tie the handle so that the lever is halfway to the
>>> grip, crack the bleeder on the caliper (with a tube on it to direct
>>> the drainage), and walk away for a couple hours and let gravity do
>>> some work for you. =A0Much quicker is to zip tie the lever halfway,
> and
>>> use a small vacuum pump rig to PULL the fluid through. =A0Once most of
>>> the air is gone, you should be able to develop some pressure to
>>> complete the bleeding in the normal manner. =A0YES to DOT 3/4. =A0NO
> to
>>> Mil Spec 5606 hydraulic oil. =A0As an experiment, I tossed some
>>> motorcycle brake bits in a jar of 5606. =A0They turned into something
>>> other than brake bits pretty quickly.- Hide quoted text -
>>>
>>> - Show quoted text -
>>
>>Clarification on the quicker way to purge the air out: Zip tie the
>>lever at half travel, use a vacuum pump ON THE CALIPER BLEEDER to pull
>>brake fluid through. Hope this helps
>>

[[email protected]]

On 22 Oct, 19:05, "Tim Mara" > wrote:
> there is now a new bleeder system from TOST
> for details please seehttp://www.wingsandwheels.com/page32.htm
> tim
> Please visit the Wings & Wheels website atwww.wingsandwheels.com
>
> "Mike McCarron" > wrote in message
>
> ...
>
>
>
> > How can one tell where to position the lever? *Half way through it's total
> > travel or some other location?
>
> > MC
>
> > At 16:33 22 October 2008, Uncle Fuzzy wrote:
> >>On Oct 22, 8:22=A0am, Uncle Fuzzy *wrote:
> >>> On Oct 22, 8:01=A0am, "bumper" *wrote:
>
> >>> > Yup, what JJ said. The "red stuff" is Mil Spec 5606 hydraulic oil
> > and
> >>i=
> >>s
> >>> > compatible with Buna-N O-rings and seals. It's also commonly used
> > in
> >>th=
> >>e USA
> >>> > for most small GA aircraft.
>
> >>> > DOT automotive brake fluid, the "clear stuff", most often
> > glycol-ether
> >>> > based, and is compatible with EPDM rubber seals.
>
> >>> > If you are switching parts from one fluid to the other, you gotta
> >>chang=
> >>e the
> >>> > rubber stuff.
>
> >>> > bumper
>
> >>> > "JJ Sinclair" *wrote in message
>
> ...=
> >>..
>
> >>> > > Why didn't it work, Mike? Hydraulics are hydraulics, the Clevland
> >>> > > brake slave cylinder doesn't know (or care) where that pressure
> > is
> >>> > > coming from? Make sure you have compatible seals. What type fluid
> >>doe=
> >>s
> >>> > > BMW use? Can't mix the red stuff with the clear stuff.
> >>> > > JJ
>
> >>> > > Mike McCarron wrote:
> >>> > >> JJ,
>
> >>> > >> I did purchase a master cylinder from a BMW motorcycle dealer
> > that
> >>d=
> >>id
> >>> > >> fit
> >>> > >> in place. =A0Unfortunately it did not function properly. =A0It
> > was
> >>p=
> >>roperly
> >>> > >> bled and all but it did not work. =A0I don't know what to do
> > next.
> >>=
> >>=A0There
> >>> > >> must be at least 100 of these gliders in the US that will need a
> >>mas=
> >>ter
> >>> > >> cylinder replacement in the future. =A0I don't see how we can
> > junk
> >>a=
> >> $30K
> >>> > >> glider for lack of a functioning master cylinder.
>
> >>> > >> Thanks for your comment,
>
> >>> > >> MC
>
> >>> > >> At 13:41 22 October 2008, JJ Sinclair wrote:
> >>> > >> >If memory serves me, its a motorcycle master cylinder BMW? I
> >>believ=
> >>e
> >>> > >> >they cut it down from the original, good luck getting your
> >>inspecto=
> >>r
> >>> > >> >to sign off on installing it!
> >>> > >> >JJ
>
> >>> > >> >Mike McCarron wrote:
> >>> > >> >> My club has a 1983 Grob 103 Twin II that needs a new master
> >>cylin=
> >>der.
> >>> > >> >Over
> >>> > >> >> the years the Grob factory has made changes to the system
> >>without=
> >> full
> >>> > >> >> documentation and as a result the US distributor can not be
> > sure
> >>=
> >>of
> >>> > >> how
> >>> > >> >I
> >>> > >> >> go about purchasing the proper master cylinder for this
> > glider.
>
> >>> > >> >> If you or anyone you know has replaced the master cylinder on
> > a
> >>> > >> vintage
> >>> > >> >> Grob 103 Twin II recently I would appreciate your input on
> > where
> >>=
> >>I
> >>> > >> might
> >>> > >> >> purchase the correct system.
>
> >>> > >> >> Thank you,
>
> >>> > >> >> Mike- Hide quoted text -
>
> >>> > - Show quoted text -
>
> >>> In our club Grob 103, the master cylinder is a Magura motorcycle front
> >>> brake master cylinder. =A0Magura makes parts for a bunch of bikes, and
> >>> for the aftermarket. Motorcycle front brake master cylinders come in a
> >>> variety of piston diameters. =A0They are also somewhat weird to bleed.
> >>> They won't develop pressure unless almost all of the air is bled out
> >>> of the system. =A0"Pumping" one endlessly has no effect. =A0On a
> > bike,
> >>on=
> >>e
> >>> trick is to zip tie the handle so that the lever is halfway to the
> >>> grip, crack the bleeder on the caliper (with a tube on it to direct
> >>> the drainage), and walk away for a couple hours and let gravity do
> >>> some work for you. =A0Much quicker is to zip tie the lever halfway,
> > and
> >>> use a small vacuum pump rig to PULL the fluid through. =A0Once most of
> >>> the air is gone, you should be able to develop some pressure to
> >>> complete the bleeding in the normal manner. =A0YES to DOT 3/4. =A0NO
> > to
> >>> Mil Spec 5606 hydraulic oil. =A0As an experiment, I tossed some
> >>> motorcycle brake bits in a jar of 5606. =A0They turned into something
> >>> other than brake bits pretty quickly.- Hide quoted text -
>
> >>> - Show quoted text -
>
> >>Clarification on the quicker way to purge the air out: *Zip tie the
> >>lever at half travel, use a vacuum pump ON THE CALIPER BLEEDER to pull
> >>brake fluid through. *Hope this helps- Hide quoted text -

One possibly non-obvious thing is that if there are flexible
rubber hoses in the pressure side of the system they you
need to check that they are servicable.

With age they lose stiffness and expand sufficiently under
pressure such that the brakes do not work. Indistinguisable
symptoms from air in the system.

If you have one that is 30 years old then I would just get a new one.

I don't suppose that the fancy teflon ones suffer from this.
http://www.goodridge.co.uk/buy-goodridge-hoses.htm

[Don Johnstone[_3_]]

1 The master cylinder in the Grob103 Acro is a BMW front brake master
cylinder from a R series motorcycle. The actuating lever is the cut off
front brake lever.

2 It is virtually impossible to bleed the brakes in the normal way and the
following method is used by the Royal Air Force techies who service the 99
Grobs owned by the RAF

a. Cover the open master cylinder in the cockpit with a cloth, important
if you do not want fluid all over the floor.

b With the slave unit removed from the wheel but attached to the pipe
remove the slave piston from the cylinder.

c Turn the unit so the slave cylinder is facing upwards and fill with
DOT3/4 fluid, it tells you the correct one on the master cylinder cover.
Make sure that the bottom of the cylinder is the lowest point.

d Insert the piston and very slowly push completely home in the cylinder,
and I do mean very slowly forcing fluid and any trapped air upwards into
the master cylinder. Clean up the slave and reassemble.

e Fill the master cylinder in the normal way.

Saves spending a fortune on specialist tools which may or may not work.

Soaring Oxford Ltd. Fosse Rd, Syerston, Newark, Nottinghamshire NG23 5NG.
Tel: +441636 525318 are the UK suppliers and supply the RAF. They may help
in sourcing the correct cylinder.

[Jim Beckman[_2_]]

This thread started with the necessity of replacing the brake master
cylinder, right? Did anyone mention why it needed replacement? My first
guess is wear or corrosion in the cylinder bore causing it to leak
pressure. If this is the case, there are places that will bore the
cylinder and sleeve it with either stainless steel or brass. It's done
all the time for old cars.

On the other hand, I don't know anything about the legality of doing that
for an aircraft brake system. And on the Gripping Hand, I would probably
do it that way myself.

Jim Beckman

[P Ilatus[_1_]]

There's a thread about this here:

http://www.aviationbanter.com/archive/index.php/t-22487.html


some old G103 maintenance manual on the web http://tinyurl.com/G103MM
doesn't mention anything about changing brake fluid every two years as is
common in most cars, however the DG505 needs it done every 4 years.
http://tinyurl.com/5zy2wj












At 13:00 23 October 2008, Jim Beckman wrote:
>
>This thread started with the necessity of replacing the brake master
>cylinder, right? Did anyone mention why it needed replacement? My
first
>guess is wear or corrosion in the cylinder bore causing it to leak
>pressure. If this is the case, there are places that will bore the
>cylinder and sleeve it with either stainless steel or brass. It's done
>all the time for old cars.
>
>On the other hand, I don't know anything about the legality of doing
that
>for an aircraft brake system. And on the Gripping Hand, I would
probably
>do it that way myself.
>
>Jim Beckman
>
>

[P Ilatus[_1_]]

There's a thread about this here:

http://www.aviationbanter.com/archive/index.php/t-22487.html


some old G103 maintenance manual on the web http://tinyurl.com/G103MM
doesn't mention anything about changing brake fluid every two years as is
common in most cars, however the DG505 needs it done every 4 years.
http://tinyurl.com/5zy2wj












At 13:00 23 October 2008, Jim Beckman wrote:
>
>This thread started with the necessity of replacing the brake master
>cylinder, right? Did anyone mention why it needed replacement? My
first
>guess is wear or corrosion in the cylinder bore causing it to leak
>pressure. If this is the case, there are places that will bore the
>cylinder and sleeve it with either stainless steel or brass. It's done
>all the time for old cars.
>
>On the other hand, I don't know anything about the legality of doing
that
>for an aircraft brake system. And on the Gripping Hand, I would
probably
>do it that way myself.
>
>Jim Beckman
>
>

[Uncle Fuzzy]

On Oct 23, 7:15*am, P Ilatus > wrote:
> There's a thread about this here:
>
> http://www.aviationbanter.com/archive/index.php/t-22487.html
>
> some old G103 maintenance manual on the webhttp://tinyurl.com/G103MM
> doesn't mention anything about changing brake fluid every two years as is
> common in most cars, however the DG505 needs it done every 4 years.http://tinyurl.com/5zy2wj
>
> At 13:00 23 October 2008, Jim Beckman wrote:
>
>
>
>
>
> >This thread started with the necessity of replacing the brake master
> >cylinder, right? *Did anyone mention why it needed replacement? *My
> first
> >guess is wear or corrosion in the cylinder bore causing it to leak
> >pressure. *If this is the case, there are places that will bore the
> >cylinder and sleeve it with either stainless steel or brass. *It's done
> >all the time for old cars.
>
> >On the other hand, I don't know anything about the legality of doing
> that
> >for an aircraft brake system. *And on the Gripping Hand, I would
> probably
> >do it that way myself.
>
> >Jim Beckman- Hide quoted text -
>
> - Show quoted text -

I wouldn't let it go that long myself. I change the brake fluids (all
fluids really) in my bike every year. It's the water accumulated in
the automotive brake fluid that causes the corrosion that kills the
cylinders.

[bumper]

"Jim Beckman" > wrote in message
...
>
> This thread started with the necessity of replacing the brake master
> cylinder, right? Did anyone mention why it needed replacement? My first
> guess is wear or corrosion in the cylinder bore causing it to leak
> pressure. If this is the case, there are places that will bore the
> cylinder and sleeve it with either stainless steel or brass. It's done
> all the time for old cars.
>
> On the other hand, I don't know anything about the legality of doing that
> for an aircraft brake system. And on the Gripping Hand, I would probably
> do it that way myself.
>
> Jim Beckman
>

One shop that does a good job with this is:

http://www.brakecylinder.com/

Part of the problem, as has been posted before, is that DOT brake fluids are
hygroscopic. If brake parts are aluminum, then water in the fluid can
promote corrosion. Anodizing the aluminum parts, or sleeving them in the
case of caliper housings, can help prevent this. To test to see if a given
part is anodized, say a piston from a caliper, touch the part with the leads
from a ohm meter (digital meter set on ohms). The anodize layer is an
insulator and won't conduct.

bumper
QV and MKII

[Don Johnstone[_3_]]

At 13:00 23 October 2008, Jim Beckman wrote:
>
>This thread started with the necessity of replacing the brake master
>cylinder, right? Did anyone mention why it needed replacement? My
first
>guess is wear or corrosion in the cylinder bore causing it to leak
>pressure. If this is the case, there are places that will bore the
>cylinder and sleeve it with either stainless steel or brass. It's done
>all the time for old cars.
>
>On the other hand, I don't know anything about the legality of doing
that
>for an aircraft brake system. And on the Gripping Hand, I would
probably
>do it that way myself.
>
>Jim Beckman
>
Old cars normally have steel brake cyliders, the BMW part we are talking
about is aluminium. Putting a steel or brass sleeve in will almost
certainly cause corrosion (disimilar metals).
A new part is available and is not expensive. All that needs to be done is
to swap over the lever.

[Mike McCarron[_2_]]

What do you mean by "swap over the lever"?

Mike

At 22:00 23 October 2008, Don Johnstone wrote:
>At 13:00 23 October 2008, Jim Beckman wrote:
>>
>>This thread started with the necessity of replacing the brake master
>>cylinder, right? Did anyone mention why it needed replacement? My
>first
>>guess is wear or corrosion in the cylinder bore causing it to leak
>>pressure. If this is the case, there are places that will bore the
>>cylinder and sleeve it with either stainless steel or brass. It's
done
>>all the time for old cars.
>>
>>On the other hand, I don't know anything about the legality of doing
>that
>>for an aircraft brake system. And on the Gripping Hand, I would
>probably
>>do it that way myself.
>>
>>Jim Beckman
>>
>Old cars normally have steel brake cyliders, the BMW part we are talking
>about is aluminium. Putting a steel or brass sleeve in will almost
>certainly cause corrosion (disimilar metals).
>A new part is available and is not expensive. All that needs to be done
is
>to swap over the lever.
>

[BT]

the new master cylinder may not have the brake lever installed.. (attached)
as most replacement motorcycle parts do not either, the master cylinder is
separate part number from the external brake lever handle.

BT

"Mike McCarron" > wrote in message
...
> What do you mean by "swap over the lever"?
>
> Mike
>
> At 22:00 23 October 2008, Don Johnstone wrote:
>>At 13:00 23 October 2008, Jim Beckman wrote:
>>>
>>>This thread started with the necessity of replacing the brake master
>>>cylinder, right? Did anyone mention why it needed replacement? My
>>first
>>>guess is wear or corrosion in the cylinder bore causing it to leak
>>>pressure. If this is the case, there are places that will bore the
>>>cylinder and sleeve it with either stainless steel or brass. It's
> done
>>>all the time for old cars.
>>>
>>>On the other hand, I don't know anything about the legality of doing
>>that
>>>for an aircraft brake system. And on the Gripping Hand, I would
>>probably
>>>do it that way myself.
>>>
>>>Jim Beckman
>>>
>>Old cars normally have steel brake cyliders, the BMW part we are talking
>>about is aluminium. Putting a steel or brass sleeve in will almost
>>certainly cause corrosion (disimilar metals).
>>A new part is available and is not expensive. All that needs to be done
> is
>>to swap over the lever.
>>

[Don Johnstone[_3_]]

At 04:50 24 October 2008, BT wrote:
>the new master cylinder may not have the brake lever installed..
(attached)
>as most replacement motorcycle parts do not either, the master cylinder
is
>
>separate part number from the external brake lever handle.
>
>BT
>
>"Mike McCarron" wrote in message
...
>> What do you mean by "swap over the lever"?
>>
>> Mike
>>
>> At 22:00 23 October 2008, Don Johnstone wrote:
>>>At 13:00 23 October 2008, Jim Beckman wrote:
>>>>
>>>>This thread started with the necessity of replacing the brake master
>>>>cylinder, right? Did anyone mention why it needed replacement? My
>>>first
>>>>guess is wear or corrosion in the cylinder bore causing it to leak
>>>>pressure. If this is the case, there are places that will bore the
>>>>cylinder and sleeve it with either stainless steel or brass. It's
>> done
>>>>all the time for old cars.
>>>>
>>>>On the other hand, I don't know anything about the legality of doing
>>>that
>>>>for an aircraft brake system. And on the Gripping Hand, I would
>>>probably
>>>>do it that way myself.
>>>>
>>>>Jim Beckman
>>>>
>>>Old cars normally have steel brake cyliders, the BMW part we are
talking
>>>about is aluminium. Putting a steel or brass sleeve in will almost
>>>certainly cause corrosion (disimilar metals).
>>>A new part is available and is not expensive. All that needs to be
done
>> is
>>>to swap over the lever.
>>>
>
>
>

[Andrew Warbrick]

At 10:15 24 October 2008, Don Johnstone wrote:
>At 04:50 24 October 2008, BT wrote:
>>the new master cylinder may not have the brake lever installed..
>(attached)
>>as most replacement motorcycle parts do not either, the master cylinder
>is
>>
>>separate part number from the external brake lever handle.
>>
>>BT
>>
>>"Mike McCarron" wrote in message
...
>>> What do you mean by "swap over the lever"?
>>>
>>> Mike
>>>
>>> At 22:00 23 October 2008, Don Johnstone wrote:
>>>>At 13:00 23 October 2008, Jim Beckman wrote:
>>>>>
>>>>>This thread started with the necessity of replacing the brake master
>>>>>cylinder, right? Did anyone mention why it needed replacement? My
>>>>first
>>>>>guess is wear or corrosion in the cylinder bore causing it to leak
>>>>>pressure. If this is the case, there are places that will bore the
>>>>>cylinder and sleeve it with either stainless steel or brass. It's
>>> done
>>>>>all the time for old cars.
>>>>>
>>>>>On the other hand, I don't know anything about the legality of
doing
>>>>that
>>>>>for an aircraft brake system. And on the Gripping Hand, I would
>>>>probably
>>>>>do it that way myself.
>>>>>
>>>>>Jim Beckman
>>>>>
>>>>Old cars normally have steel brake cyliders, the BMW part we are
>talking
>>>>about is aluminium. Putting a steel or brass sleeve in will almost
>>>>certainly cause corrosion (disimilar metals).
>>>>A new part is available and is not expensive. All that needs to be
>done
>>> is
>>>>to swap over the lever.
>>>>
>>
>>
>>
>

Look on the bright side, at least he isn't in the UK. I'm pretty sure
BMW don't supply brake cylinders with EASA release certificates. I can
imagine:

1. Brake cylinder from BMW: £100
2. Identical BMW brake cylinder the man from EASA has sprinkled magic
pixie dust on: £350
3. ??????
4. Profit

[haven]

On Oct 24, 4:30*am, Andrew Warbrick
> wrote:
> At 10:15 24 October 2008, Don Johnstone wrote:
>
>
>
> >At 04:50 24 October 2008, BT wrote:
> >>the new master cylinder may not have the brake lever installed..
> >(attached)
> >>as most replacement motorcycle parts do not either, the master cylinder
> >is
>
> >>separate part number from the external brake lever handle.
>
> >>BT
>
> >>"Mike McCarron" *wrote in message
> ...
> >>> What do you mean by "swap over the lever"?
>
> >>> Mike
>
> >>> At 22:00 23 October 2008, Don Johnstone wrote:
> >>>>At 13:00 23 October 2008, Jim Beckman wrote:
>
> >>>>>This thread started with the necessity of replacing the brake master
> >>>>>cylinder, right? *Did anyone mention why it needed replacement? *My
> >>>>first
> >>>>>guess is wear or corrosion in the cylinder bore causing it to leak
> >>>>>pressure. *If this is the case, there are places that will bore the
> >>>>>cylinder and sleeve it with either stainless steel or brass. *It's
> >>> done
> >>>>>all the time for old cars.
>
> >>>>>On the other hand, I don't know anything about the legality of
> doing
> >>>>that
> >>>>>for an aircraft brake system. *And on the Gripping Hand, I would
> >>>>probably
> >>>>>do it that way myself.
>
> >>>>>Jim Beckman
>
> >>>>Old cars normally have steel brake cyliders, the BMW part we are
> >talking
> >>>>about is aluminium. Putting a steel or brass sleeve in will almost
> >>>>certainly cause corrosion (disimilar metals).
> >>>>A new part is available and is not expensive. All that needs to be
> >done
> >>> is
> >>>>to swap over the lever.
>
> Look on the bright side, at least he isn't in the UK. I'm pretty sure
> BMW don't supply brake cylinders with EASA release certificates. I can
> imagine:
>
> 1. Brake cylinder from BMW: £100
> 2. Identical BMW brake cylinder the man from EASA has sprinkled magic
> pixie dust on: £350
> 3. ??????
> 4. Profit

After replacing the master cylinder on our ship we found that the
problem was with the brake line linking the two cylinders. When we
replaced it the problem of poor braking was solved. Must have been
unobservable expansion within the OE line!

[Mike McCarron[_2_]]

Where did you find a brake line to purchase that would fit the Grob?

Mike

At 12:42 24 October 2008, haven wrote:
>On Oct 24, 4:30=A0am, Andrew Warbrick
> wrote:
>> At 10:15 24 October 2008, Don Johnstone wrote:
>>
>>
>>
>> >At 04:50 24 October 2008, BT wrote:
>> >>the new master cylinder may not have the brake lever installed..
>> >(attached)
>> >>as most replacement motorcycle parts do not either, the master
>cylinder
>> >is
>>
>> >>separate part number from the external brake lever handle.
>>
>> >>BT
>>
>> >>"Mike McCarron" =A0wrote in message
>> ...
>> >>> What do you mean by "swap over the lever"?
>>
>> >>> Mike
>>
>> >>> At 22:00 23 October 2008, Don Johnstone wrote:
>> >>>>At 13:00 23 October 2008, Jim Beckman wrote:
>>
>> >>>>>This thread started with the necessity of replacing the brake
>master
>> >>>>>cylinder, right? =A0Did anyone mention why it needed replacement?
=
>=A0My
>> >>>>first
>> >>>>>guess is wear or corrosion in the cylinder bore causing it to
leak
>> >>>>>pressure. =A0If this is the case, there are places that will bore
>th=
>e
>> >>>>>cylinder and sleeve it with either stainless steel or brass.
>=A0It's
>> >>> done
>> >>>>>all the time for old cars.
>>
>> >>>>>On the other hand, I don't know anything about the legality of
>> doing
>> >>>>that
>> >>>>>for an aircraft brake system. =A0And on the Gripping Hand, I
would
>> >>>>probably
>> >>>>>do it that way myself.
>>
>> >>>>>Jim Beckman
>>
>> >>>>Old cars normally have steel brake cyliders, the BMW part we are
>> >talking
>> >>>>about is aluminium. Putting a steel or brass sleeve in will almost
>> >>>>certainly cause corrosion (disimilar metals).
>> >>>>A new part is available and is not expensive. All that needs to be
>> >done
>> >>> is
>> >>>>to swap over the lever.
>>
>> Look on the bright side, at least he isn't in the UK. I'm pretty
sure
>> BMW don't supply brake cylinders with EASA release certificates. I
can
>> imagine:
>>
>> 1. Brake cylinder from BMW: =A3100
>> 2. Identical BMW brake cylinder the man from EASA has sprinkled magic
>> pixie dust on: =A3350
>> 3. ??????
>> 4. Profit
>
>After replacing the master cylinder on our ship we found that the
>problem was with the brake line linking the two cylinders. When we
>replaced it the problem of poor braking was solved. Must have been
>unobservable expansion within the OE line!
>

[Don Johnstone[_3_]]

At 13:45 24 October 2008, Mike McCarron wrote:
>
>
>Where did you find a brake line to purchase that would fit the Grob?
>
Almost any motorcycle shop will make one up for you. If you get one that
has a steel braid outer you will, as a previous poster said, get rid of
the problem of brake line expansion. I have to say that while brake pipe
expansion is a problem with mootor cycle brakes, given the very short line
on the Grob I am surprised that was a problem.

[haven]

On Oct 24, 6:45*am, Mike McCarron > wrote:
> Where did you find a brake line to purchase that would fit the Grob?
>
> Mike
>
> At 12:42 24 October 2008, haven wrote:
>
> >On Oct 24, 4:30=A0am, Andrew Warbrick
> > wrote:
> >> At 10:15 24 October 2008, Don Johnstone wrote:
>
> >> >At 04:50 24 October 2008, BT wrote:
> >> >>the new master cylinder may not have the brake lever installed..
> >> >(attached)
> >> >>as most replacement motorcycle parts do not either, the master
> >cylinder
> >> >is
>
> >> >>separate part number from the external brake lever handle.
>
> >> >>BT
>
> >> >>"Mike McCarron" =A0wrote in message
> >> ...
> >> >>> What do you mean by "swap over the lever"?
>
> >> >>> Mike
>
> >> >>> At 22:00 23 October 2008, Don Johnstone wrote:
> >> >>>>At 13:00 23 October 2008, Jim Beckman wrote:
>
> >> >>>>>This thread started with the necessity of replacing the brake
> >master
> >> >>>>>cylinder, right? =A0Did anyone mention why it needed replacement?
> =
> >=A0My
> >> >>>>first
> >> >>>>>guess is wear or corrosion in the cylinder bore causing it to
> leak
> >> >>>>>pressure. =A0If this is the case, there are places that will bore
> >th=
> >e
> >> >>>>>cylinder and sleeve it with either stainless steel or brass.
> >=A0It's
> >> >>> done
> >> >>>>>all the time for old cars.
>
> >> >>>>>On the other hand, I don't know anything about the legality of
> >> doing
> >> >>>>that
> >> >>>>>for an aircraft brake system. =A0And on the Gripping Hand, I
> would
> >> >>>>probably
> >> >>>>>do it that way myself.
>
> >> >>>>>Jim Beckman
>
> >> >>>>Old cars normally have steel brake cyliders, the BMW part we are
> >> >talking
> >> >>>>about is aluminium. Putting a steel or brass sleeve in will almost
> >> >>>>certainly cause corrosion (disimilar metals).
> >> >>>>A new part is available and is not expensive. All that needs to be
> >> >done
> >> >>> is
> >> >>>>to swap over the lever.
>
> >> Look on the bright side, at least he isn't in the UK. I'm pretty
> sure
> >> BMW don't supply brake cylinders with EASA release certificates. I
> can
> >> imagine:
>
> >> 1. Brake cylinder from BMW: =A3100
> >> 2. Identical BMW brake cylinder the man from EASA has sprinkled magic
> >> pixie dust on: =A3350
> >> 3. ??????
> >> 4. Profit
>
> >After replacing the master cylinder on our ship we found that the
> >problem was with the brake line linking the two cylinders. *When we
> >replaced it the problem of poor braking was solved. *Must have been
> >unobservable expansion within the OE line!

As I remember, it came from Grob in Bluffton, OH but now they are out
of the parts supply business ?!

[[email protected]]

Everyone has covered the topic well but I'll add my 2 cents having
repaired our 103 brake. Yes, it is a Magura master cylinder as used
on BMWs. All they did was cut off most of the brake lever and mount a
cable to the stub to actuate it. Yes, bleeding from the bottom of the
system (slave) works best. Here's a little trick - any marine supply
depot sells a plastic pump for replacing bottom end oil in outboard
motors. It looks like a shampoo or epoxy pump and screws onto a
standard oil, or coincidentaly, brake fluid bottle. Screw it on the
bottle, push the tubing onto the cracked open caliper bleed nipple and
pump slowly. It forces the brake fluid up. Have someone at the
master cylinder with a towel wrapped around it to take care of
overflow. It is always easier to force air bubbles upwards in a
hydraulic system then to force them downwards. It is faster then from
the top and a whole lot let frustrating.

Another hint ... don't worry about replacing the entire master
cylinder, Just go into a BMW motorcycle dealer and buy a rebuild kit
(about $75). It includes a new piston, spring and seals. (I can't
recall the bore size but these kits care reasonably universal - all
you need to do it confirm the size at the parts desk.) Use a very
fine emery cloth or wet sandpaper to gentle hone the cylinder and put
it all together. Usually the problem is the seals, not pitting of the
cylinder. Total job takes about 1.5 hours including removing and
replacing the cylinder.