K21 brake parts

[Stuart Kinnear]

Does anyone know of an automotive source for the complete brake caliper
Stuart

[Ken Reynolds]

"Stuart Kinnear" > wrote in message
...
> Does anyone know of an automotive source for the complete brake caliper
> Stuart
>Tost Catalog says K21 uses Cleveland wheel . It is reasonable to assume
>its also a cleveland brake.
Aircraft Spruce among others sell Cleveland stuff
Ken Reynolds

[nyffeler]

In article >, "Stuart Kinnear" > wrote:
>Does anyone know of an automotive source for the complete brake caliper
>Stuart

Slightliy of topic, but important.

NEVER use automotive brake fluid for the brakes in gliders!
Automotive brake fluid will destroy the seals.

Peter Nyffeler (Y7 HB-1689)

[Peter Hermann]

nyffeler > wrote:
> "Stuart Kinnear" > wrote:
> >Does anyone know of an automotive source for the complete brake caliper
> >Stuart
>
> Slightliy of topic, but important.

this is in no way off-topic:

>
> NEVER use automotive brake fluid for the brakes in gliders!
> Automotive brake fluid will destroy the seals.
>
> Peter Nyffeler (Y7 HB-1689)

BTW, it is not wise to have hydraulic brakes in a glider
to fly upside down: I have experienced twice full loss of
braking action after touch down. :-(

--
(+49)0711-685-872-44(Fax79)
--Nobelstr.19 Raum 0.030, D-70569 Stuttgart IHR Hoechstleistungsrechnen
--http://www.ihr.uni-stuttgart.de/

[Bob Kuykendall]

Earlier, nyffeler wrote:

> Slightliy of topic, but important.
>
> NEVER use automotive brake fluid for the brakes in gliders!
> Automotive brake fluid will destroy the seals.

Except, of course, in those rare but not non-existant cases where the
brakes were designed around automotive pistons and seals. A good
example is the early (pre-MATCO) Rosenhan drum units used on some 1960s
American gliders.

[bumper]

Another example is the Stemme S10 series, which uses DOT fluid. Stemme uses
a Cleveland 300 caliper with the seals changed from Buna-N to EPDM rubber.

bumper


"Bob Kuykendall" > wrote in message
oups.com...
> Earlier, nyffeler wrote:
>
>> Slightliy of topic, but important.
>>
>> NEVER use automotive brake fluid for the brakes in gliders!
>> Automotive brake fluid will destroy the seals.
>
> Except, of course, in those rare but not non-existant cases where the
> brakes were designed around automotive pistons and seals. A good
> example is the early (pre-MATCO) Rosenhan drum units used on some 1960s
> American gliders.
>

[Gary Evans]

DG also uses brake fluid with a EPDM (ethylene propylene)
O-ring at least on the 800/808. I would check the manual
for each specific model to determine which is used.
Even if you were to change the caliper O-ring to EPDM
you would still need to verify what is used for a seal
in the master cylinder and lines.

At 16:30 21 June 2006, Bumper wrote:
>Another example is the Stemme S10 series, which uses
>DOT fluid. Stemme uses
>a Cleveland 300 caliper with the seals changed from
>Buna-N to EPDM rubber.
>
>bumper
>
>
>'Bob Kuykendall' wrote in message
oups.com...
>> Earlier, nyffeler wrote:
>>
>>> Slightliy of topic, but important.
>>>
>>> NEVER use automotive brake fluid for the brakes in
>>>gliders!
>>> Automotive brake fluid will destroy the seals.
>>
>> Except, of course, in those rare but not non-existant
>>cases where the
>> brakes were designed around automotive pistons and
>>seals. A good
>> example is the early (pre-MATCO) Rosenhan drum units
>>used on some 1960s
>> American gliders.
>>
>
>
>

[Basil]

And Duo Discus. In fact most tost calipers and all Tost master
cylinders.

On 21 Jun 2006 17:09:09 GMT, Gary Evans
> wrote:

>DG also uses brake fluid with a EPDM (ethylene propylene)
>O-ring at least on the 800/808. I would check the manual
>for each specific model to determine which is used.
>Even if you were to change the caliper O-ring to EPDM
>you would still need to verify what is used for a seal
>in the master cylinder and lines.
>
>At 16:30 21 June 2006, Bumper wrote:
>>Another example is the Stemme S10 series, which uses
>>DOT fluid. Stemme uses
>>a Cleveland 300 caliper with the seals changed from
>>Buna-N to EPDM rubber.
>>
>>bumper
>>
>>
>>'Bob Kuykendall' wrote in message
oups.com...
>>> Earlier, nyffeler wrote:
>>>
>>>> Slightliy of topic, but important.
>>>>
>>>> NEVER use automotive brake fluid for the brakes in
>>>>gliders!
>>>> Automotive brake fluid will destroy the seals.
>>>
>>> Except, of course, in those rare but not non-existant
>>>cases where the
>>> brakes were designed around automotive pistons and
>>>seals. A good
>>> example is the early (pre-MATCO) Rosenhan drum units
>>>used on some 1960s
>>> American gliders.
>>>
>>
>>
>>
>
>

[Gary Evans]

Tost calipers are in fact Cleveland parts with differant
O-rings and I assume the same may be true for their
master cylinders. All of this branding can get confusing.
Being U.S. manufacture replacement parts (except the
EPDM O-rings) can be obtained through retailers like
Aircraft Spruce and the special O-rings through an
industrial supplier such as MSC.

At 12:12 22 June 2006, Basil wrote:
>And Duo Discus. In fact most tost calipers and all
>Tost master
>cylinders.
>
>On 21 Jun 2006 17:09:09 GMT, Gary Evans
> wrote:
>
>>DG also uses brake fluid with a EPDM (ethylene propylene)
>>O-ring at least on the 800/808. I would check the manual
>>for each specific model to determine which is used.
>>Even if you were to change the caliper O-ring to EPDM
>>you would still need to verify what is used for a seal
>>in the master cylinder and lines.
>>
>>At 16:30 21 June 2006, Bumper wrote:
>>>Another example is the Stemme S10 series, which uses
>>>DOT fluid. Stemme uses
>>>a Cleveland 300 caliper with the seals changed from
>>>Buna-N to EPDM rubber.
>>>
>>>bumper
>>>
>>>
>>>'Bob Kuykendall' wrote in message
oups.com...
>>>> Earlier, nyffeler wrote:
>>>>
>>>>> Slightliy of topic, but important.
>>>>>
>>>>> NEVER use automotive brake fluid for the brakes in
>>>>>gliders!
>>>>> Automotive brake fluid will destroy the seals.
>>>>
>>>> Except, of course, in those rare but not non-existant
>>>>cases where the
>>>> brakes were designed around automotive pistons and
>>>>seals. A good
>>>> example is the early (pre-MATCO) Rosenhan drum units
>>>>used on some 1960s
>>>> American gliders.
>>>>
>>>
>>>
>>>
>>
>>
>

[bumper]

Gary is, of course, correct. Couple of additional things to be aware of:
Some of the earlier (pre about 1998) Cleveland caliper aluminum pistons were
not anodized, thus were subject to corrosion. This could be a problem, as
the automotive brake fluid is hygroscopic. Corrosion in the O-ring groove
and piston bore results in brake fluid contamination of the rotor and
resulting loss of brake effectiveness.

For experimental types, Sierra Brass (think that's the name) will bore out
and brass line the caliper bore, a procedure done on old Corvettes and other
cars. Cost in about $80 IIRC. Solves the leakage problem nicely.

all the best,

bumper
"Gary Evans" > wrote in message
...
> Tost calipers are in fact Cleveland parts with differant
> O-rings and I assume the same may be true for their
> master cylinders. All of this branding can get confusing.
> Being U.S. manufacture replacement parts (except the
> EPDM O-rings) can be obtained through retailers like
> Aircraft Spruce and the special O-rings through an
> industrial supplier such as MSC.
>
> At 12:12 22 June 2006, Basil wrote:
>>And Duo Discus. In fact most tost calipers and all
>>Tost master
>>cylinders.
>>
>>On 21 Jun 2006 17:09:09 GMT, Gary Evans
>> wrote:
>>
>>>DG also uses brake fluid with a EPDM (ethylene propylene)
>>>O-ring at least on the 800/808. I would check the manual
>>>for each specific model to determine which is used.
>>>Even if you were to change the caliper O-ring to EPDM
>>>you would still need to verify what is used for a seal
>>>in the master cylinder and lines.
>>>
>>>At 16:30 21 June 2006, Bumper wrote:
>>>>Another example is the Stemme S10 series, which uses
>>>>DOT fluid. Stemme uses
>>>>a Cleveland 300 caliper with the seals changed from
>>>>Buna-N to EPDM rubber.
>>>>
>>>>bumper
>>>>
>>>>
>>>>'Bob Kuykendall' wrote in message
oups.com...
>>>>> Earlier, nyffeler wrote:
>>>>>
>>>>>> Slightliy of topic, but important.
>>>>>>
>>>>>> NEVER use automotive brake fluid for the brakes in
>>>>>>gliders!
>>>>>> Automotive brake fluid will destroy the seals.
>>>>>
>>>>> Except, of course, in those rare but not non-existant
>>>>>cases where the
>>>>> brakes were designed around automotive pistons and
>>>>>seals. A good
>>>>> example is the early (pre-MATCO) Rosenhan drum units
>>>>>used on some 1960s
>>>>> American gliders.
>>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>
>
>
>

[chrisrobsoar]

Ken Reynolds wrote:
> "Stuart Kinnear" > wrote in message
> ...
> > Does anyone know of an automotive source for the complete brake caliper
> > Stuart
> >Tost Catalog says K21 uses Cleveland wheel . It is reasonable to assume
> >its also a cleveland brake.
> Aircraft Spruce among others sell Cleveland stuff
> Ken Reynolds

I agree with the other postings, do not try to mix automotive parts
with the K21 Cleveland wheel brakes. The disc is expensive and should
be replaced when it gets too thin (the limit is in the manual). If the
pads are worn and the disc is out of limits the pistons can extend too
far out of the calliper and pop the seals, leaking fluid, spilling onto
the tyre, which does in no good at all. The brake system then requires
a complete rebuild.

We have three K21s, two do about 800hrs per year and the other one
about 200hrs per year. The discs are replaced about twice per year and
the pads about three times per year. Having a spare wheel, calliper and
brake pads speeds up the process. Be aware that you can get long life
pads, but they must not be used on stainless steel discs. I keep an old
worn disc that has been worn down to the minimum limit that makes
checking wear easy. The pads are easy to replace, each pad is held by
three rivets and can either be drilled out or punched out. The new set
of pads are fixed with new rivets, supplied with the pads and fitted
either will a screw clamp press or a hammer and punch set. Beware the
pads are rather brittle.

Removing the calliper is easy but the bolts must be wire locked with
stainless steel locking wire. The whole system must be bleed. It is
best to use a large syringe.

Note that the linkage needs to be adjusted so that full air-brake can
be achieved and that sufficient movement is applied to the master
cylinder.

As the pads can be used of military aircraft, they required an "end
user certificate waiver" and are now subject to International Trade in
Armament Regulations (ITAR). No Joke.

Removing the wheel requires thin walled sockets (I think 17mm from
memory), I have a ground down set in my toolbox.

Replacing the wheel bearings is also rather problematic, they are cone
roller bearings. The seats have to driven or pressed out. When the new
seats are installed the gaps have to be adjusted will shims to
eliminate almost all of the sideways float. The wheel is in two halves
joined by six socket headed high tensile steel bolts, these must be
torqued to the required setting (in the manual for the wheel), it is
best to replace the nylock nuts every time the wheel is taken apart. To
avoid nipping the tube, partiarly inflate the tube during assembly. The
standard tube valve protrudes too far and can fowl the brake, so short
lengths of tube (fuel pipe) are used to provide clearance. The same
trick is used on the nose wheel and the tail wheel. The wheels can also
corrode so I give them a light coating of a silicon or PTFE spray (GT
85 as used on bike chains is very good). We replace the main wheel
bearings and tyres every three years after about 2,000 - 2,500hrs,
12,000 to 15,000 launches and landings.

Our club does about 10,000 launches per year (90% by winch) and we land
on grass. The nose wheel pressure has been reduced and the tail wheel
pressure increased in order to minimise damage to the glider.

If the nose wheel bearings stick the wheel rotates on the fixed axel
and as this is a metal on metal surface wears quickly and makes a lot
of noise on the winch launch (the high speed winds up the wheel and
requires the glider to be flown very slowly before it stops). The fix
is to use some sot of bearing locking solution when the axel is fitted.
The tip is to fit the axle, push it out an inch apply the solution,
push it in and pull it out until enough gets onto the portion of the
shaft in the bearing and tighten it up. Leaving the glider with the
wheel off the ground to cure helps.

We tried to minimise the damage to tail wheels by filling them with
foam; it just transferred the damage to the rest of the glider! AS was
about to test this fix when our technical officer (Joe Fisher) advised
them that it did not work. (Joe designed the rear seat hand rudder
modification for the K21, our gliders can be operated by hand rudder
from either seat).

The only solution to damaging the tail wheels is to increase the
pressure in the tail wheel and to land properly. Ensuring that the
glider is balanced on the main wheel, when turning the glider helps to
reduce damage to the sidewall of the tyre.

I will dig out the standard pressures and what we use now.


Chris

p. s. I was the Director for gliders, safety officer and vice-chairman,
at our club and currently I am our full time weekly course instructor;
so K21 HPV is my office. In the UK our agent is Peter Wells at
Zuluglasstek, who is very helpful if anyone encounters unusual
problems.


NB The DG505 etc also uses automotive brake fluid DOT3/DOT4. Never use
the wrong fluid as it eats the seals.