Cobra surge brakes on mountain grades.

My new (to me) Ventus C came with a decidedly old Cobra trailer. When
I pulled the wheel drums (one was cracked) the surfaces resembled a
dirt road after the spring run-off. I replaced drums and brake shoes
and was back in business. My first towing adventure included the long
downgrade into Calestoga at the end of which I stopped for gas, and
casually rested my hand on a Cobra wheel hub in an experimental sort
of way. EEEyooouuuugh! I barely avoided second-degree burns.

Why had this happened, I wondered? I drive a stick shift Volvo and had
followed my usual practice of engine braking with intermittent use of
the car's brakes. A little thinking convinced me that the Cobra didn't
know this. Once the surge brakes were applied, they stayed on so long
as no acceleration was applied to the Volvo. The message of the wheel
hub was that the surge brakes had been engaged all the way down that
grade.

Fortunately, another mountain lay ahead of me, and after towing to the
top of Mt. St. Helena, I applied a new technique to the down grade -
tapping the accelerator briefly after each application of the brakes
so that I could feel the surge piston disengaging. Sure enough, when I
stopped at the bottom for a (very cautious) testing of the wheel hubs,
they were only mildly warm.

Most of us know enough to tie down the Cobra's hand brake, which has a
nasty habit of springing shut during a bumpy tow, but I've never heard
anything about handling surge brakes on mountain grades. Is this new
lore, or have I misses something that everybody knows?

Matt Herron

I've used surge brakes on several trailers but never seen your problem.
Just speculating since I've never taken one of those things apart, but there
should be some sort of spring inside the hitch master cylinder that holds
off trailer brake application until the surge force on the hitch exceeds the
strength of the spring. This spring would also make sure the brakes release
when not needed.

If true, it suggests that your problem might be a deteorated/misadjusted
spring or with some sort of stickyness in the master cylinder. Maybe it's
time to R&R the trailer master cylinder.

Bill Daniels


wrote in message
oups.com...
My new (to me) Ventus C came with a decidedly old Cobra trailer. When
I pulled the wheel drums (one was cracked) the surfaces resembled a
dirt road after the spring run-off. I replaced drums and brake shoes
and was back in business. My first towing adventure included the long
downgrade into Calestoga at the end of which I stopped for gas, and
casually rested my hand on a Cobra wheel hub in an experimental sort
of way. EEEyooouuuugh! I barely avoided second-degree burns.

Why had this happened, I wondered? I drive a stick shift Volvo and had
followed my usual practice of engine braking with intermittent use of
the car's brakes. A little thinking convinced me that the Cobra didn't
know this. Once the surge brakes were applied, they stayed on so long
as no acceleration was applied to the Volvo. The message of the wheel
hub was that the surge brakes had been engaged all the way down that
grade.

Fortunately, another mountain lay ahead of me, and after towing to the
top of Mt. St. Helena, I applied a new technique to the down grade -
tapping the accelerator briefly after each application of the brakes
so that I could feel the surge piston disengaging. Sure enough, when I
stopped at the bottom for a (very cautious) testing of the wheel hubs,
they were only mildly warm.

Most of us know enough to tie down the Cobra's hand brake, which has a
nasty habit of springing shut during a bumpy tow, but I've never heard
anything about handling surge brakes on mountain grades. Is this new
lore, or have I misses something that everybody knows?

Matt Herron

you have 2 problems,

the first one may be the spring, as Bill suggested,
it may also be a faulty seal (sticky) in the master
or air within the lines. Air tends to make the brake
spongy (you wouldnt notice on a trailer) but when the
fluid heats up the air expands and holds the brake on.

Your real (second) issue is you drive a volvo, and you should be reprimanded within an inch of your life for
such a crime.


bagger

bagmaker wrote:
you have 2 problems,

the first one may be the spring, as Bill suggested,
it may also be a faulty seal (sticky) in the master
or air within the lines. Air tends to make the brake
spongy (you wouldnt notice on a trailer) but when the
fluid heats up the air expands and holds the brake on.

Your real (second) issue is you drive a volvo, and you should be
reprimanded within an inch of your life for
such a crime.


bagger






World seems divided on Volvos - I recently went over to the dark side and
purchased a car with more cylinders than neccessary (5) , more power than
neccessary and more mechanical stuff than neccessary most of the time (AWD).

Mine's an XC70. Makes a very nice glider car compromise. Cavernous boot area for
all the stuff we drag around.

Pulls glider trailers, and double cab 1 tonners out of the mud with ease, the
auto gearbox is a real sybarites toy. Have to admit it is easier than towing
with my little hatchback - mainly because you never have to change gear for hills.

Drives like a luxury sedan - and has loads of space inside. Fuel economy is
reasonable for it's size and AWD at around 24mpg (10.5l/100km average over
~5000km) So around 20% more thn my 1600 hatchback did on the same job.

The only really bad thing about it is I tend to forget there is a 9.5m trailer
behind me...

At 02:12 17 May 2007, wrote:
My new (to me) Ventus C came with a decidedly old Cobra
trailer. When
I pulled the wheel drums (one was cracked) the surfaces
resembled a
dirt road after the spring run-off. I replaced drums
and brake shoes
and was back in business. My first towing adventure
included the long
downgrade into Calestoga at the end of which I stopped
for gas, and
casually rested my hand on a Cobra wheel hub in an
experimental sort
of way. EEEyooouuuugh! I barely avoided second-degree
burns.

Why had this happened, I wondered? I drive a stick
shift Volvo and had
followed my usual practice of engine braking with intermittent
use of
the car's brakes. A little thinking convinced me that
the Cobra didn't
know this. Once the surge brakes were applied, they
stayed on so long
as no acceleration was applied to the Volvo. The message
of the wheel
hub was that the surge brakes had been engaged all
the way down that
grade.

Fortunately, another mountain lay ahead of me, and
after towing to the
top of Mt. St. Helena, I applied a new technique to
the down grade -
tapping the accelerator briefly after each application
of the brakes
so that I could feel the surge piston disengaging.
Sure enough, when I
stopped at the bottom for a (very cautious) testing
of the wheel hubs,
they were only mildly warm.

Most of us know enough to tie down the Cobra's hand
brake, which has a
nasty habit of springing shut during a bumpy tow, but
I've never heard
anything about handling surge brakes on mountain grades.
Is this new
lore, or have I misses something that everybody knows?

Matt Herron


Hi Matt,

You probably don't want to hear this, but it is
my opinion and I'm sure everyone else with surge brakes
is going to hate me too, but here goes.
GET RID OF THE SURGE BRAKES. Replace them with electric
ones, with a GOOD brake controller like a Tekonsha
Prodigy or an equivalent. They are much more reliable,
require much less maintenance, are much more flexible,
and bottom line just plain work better and this is
why. (IMHO)
1. Easy to install
2. Easy to maintain
3. Brakes on trailer can be applied independently of
brakes on the car, in addition to working in unison
with the car's brakes, It is just plain nice to have
the option of tapping just the trailer's brakes when
a semi with a 20mph differential speed sets you trailer
wagging :-) BTW I could not disagree more with using
engine braking on any vehicle under 12,000lbs, that
has hydraulic brakes on it. Brake pads cost $20-$40
a set. A transmission costs more like $4,000 and the
same with a motor. Clutches are not cheap either. Just
use the brakes on the car, never ever the engine or
transmission. You are not a big rig truck, and it is
quite unnecessary for safe operation.
4. Electric brakes work as they are supposed to while
reversing, meaning they only engage when the car's
brakes are applied, as opposed to engaging during changes
in acceleration (again, at least with a good controller)
5. They never accidentally engage, like surges will
while driving down a hill sometimes
6. You keep a breakaway backup battery system in the
trailer so the brakes automatically engage in the unlikely
event of a total separation, stopping the trailers
movement and holding it there (20 minutes at max hold
is usually the typical minimum requirement for the
breakaway kit's internal battery) as opposed to it
free rolling like what would happen with surge brakes.
Good breakaway kits have a built in charger and a charge
indicator test light, that charges automatically while
engaged to the tow vehicle.
7. You can adjust the brakes, WHILE DRIVING, to suit
ever changing road conditions, like mountains, hills,
curvy roads, thick traffic, open road, etc; meaning
the voltage they initially engage at and how quickly
they ramp up to full holding power is adjustable while
in motion, and quite easily. (most good elec brake
controllers have this feature, coupled with an output
voltage readout)
8. Much more reliable after sitting around unused for
a season or two, and are easily tested. I know more
than one person that has been in a rear-end incident,
because unknown to them the finicky surge mechanism
froze up or got sticky (Dick Johnson is one of these
people, but it was not his trailer and he was not driving).
I'm sure there have been worse accidents due to this,
but that is just my speculation.
9. Parts are readily available, and do not need to
be ordered form Germany
10. The system is inexpensive, my brake system cost
me less than $400 (smart shopping that is, but it can
be done even dumb shopping for less than $600) including
a new axle and a top of the line controller.

I would be more than happy to put together a parts
list for you, or anyone else interested in converting
their trailer to electric brakes, based on the individual
trailer. It is quite an easy conversion, and there
are many benefits to this type of system. Me personally,
I want to do everything in my power to protect my aircraft,
and electric brakes is one way to do that. Again, this
is all IMHO, and I have no ties to the brake industry,
or any others. Bottom line it that good electric brakes
can by far outperform any surge system, in the short
or long term. It is clearly a superior design. Sorry
to anyone with surge brakes that this offends. Lucky
for you it is usually cheaper to switch over to a full
electric system than to fix problems you will run into.
The only disadvantage I know of is the trailer can
then only be safely towed (if you consider brakes a
necessity for safety, which you should) by the vehicle
with the controller installed in it. A small price
to pay I'd say.

Paul Hanson


"Do the usual, unusually well"--Len Niemi

Hi Matt,

You probably don't want to hear this, but it is
my opinion and I'm sure everyone else with surge brakes
is going to hate me too, but here goes.
GET RID OF THE SURGE BRAKES. Replace them with electric
ones, with a GOOD brake controller like a Tekonsha
Prodigy or an equivalent.

This is the same advice I have heard from several trailer shops. They said
they don't even sell surge brakes anymore because of customer complaints.
The replacement involves a new axle with electric brakes and the tow vehicle
controller. I'd guess about $1200.

Bill Daniels

On May 16, 10:10 pm, wrote:
at the end of which I stopped for gas, and
casually rested my hand on a Cobra wheel hub in an experimental sort
of way. EEEyooouuuugh! I barely avoided second-degree burns.


This is one of those lines that reminded me of a Charlie Spratt
article on towing. His method for performing the same check was to
spit on the hubs. If it hissed on contact then no touchy with hand.

I filed that one away for future reference. Perhaps others can
benefit from his wisdom as well.

-bob

At 14:48 17 May 2007, Bill Daniels wrote:
Hi Matt,

You probably don't want to hear this, but it is

my opinion and I'm sure everyone else with surge brakes
is going to hate me too, but here goes. GET RID
OF THE SURGE BRAKES. Replace them with electric ones,
with a GOOD
brake controller like a Tekonsha
Prodigy or an equivalent.

This is the same advice I have heard from several trailer
shops. They said
they don't even sell surge brakes anymore because of
customer complaints.
The replacement involves a new axle with electric brakes
and the tow vehicle
controller. I'd guess about $1200.

Bill Daniels



Thanks for backing me up on this Bill, you are actually
the one that got me on the electric brake kick (although
you probably don't remember) while I was visiting Sean
in 2005 with Towing my Sisu back from Elmira to Ca.
Thanks for turning me on to this setup, prices are
a bit cheaper than you think though. ;-)

Here is a link to a good online trailer parts supplier,
to give everybody an idea of prices, which does come
out to to around $600 on average, without even ebaying
or buying used which could obviously save even more.

http://www.easternmarine.com/em_store/trailerbrakes/

Recommended parts needed a
Two 10 inch drums at around $70 apiece----------------$140
10 inch Left/right hand brake assy's at $40 each---------$80
Axle at $140(add $20 for the welding of spring mounts--$160
Good controller at (DrawTite IntelliStop is equivalent
to Tekonsha Prodigy, top of the line and key to function)$140
Breakaway kit -----------------------------------------------$40
Tie plate kit -------------------------------------------------$20

Total for parts ----------------------------------------------$580


I chose the 10 inch Dexter brakes rated for up to 3500#
(as opposed to the wimpy looking 7 inch 2000# setup,
which should also work) as well as the 3500# axle.
My original axle was straight and mounted on top of
my leaf springs, so I switched to a drop axle mounted
under the springs, which gave my suspension 2 full
extra inches of travel without changing the overall
hight of my trailer (and the frame had been bent where
the old axle bottomed out into the frame, courtesy
of the previous owners ), which has the advantage of
lowering the trailer's riding C of G, making it even
more stable. Very user friendly and robust, at a cost
of $600ish after wiring. Individual installations may
vary, but this setup would work for many, and variations
on it should not cost much more. Use this as a reference
to price out local options, and skip paying shipping
while supporting the locals, unless local taxes are
excessive.

There is a more expensive and exotic option I failed
to mention earlier, there are electrically driven hydraulic
setups (called electric over hydraulic) which gives
you the mastery of control and breakaway safety the
normal electric setup offers, while keeping your hydraulic
system basically intact. It is much more expensive,
(to setup if you have no brakes already, but comparable
in price if you compare converting existing hydraulic
setups vs replacing everything to run electric), heavy,
harder to install, and space/energy consuming but CAN
be done as an option. I'm sure some of you out there
are very attached to your hydraulic disc brakes and
such, and this might be a more suitable option for
you. I am more opposed to the surge mechanism for controlling
the braking, not the hydraulic actuation, although
pure electrics are easier to maintain long term with
less moving parts.

Again, if anyone wants specific help to set up their
personal trailer, I would be more than happy to assist.

Paul Hanson
"Do the usual, unusually well"--Len Niemi

On May 17, 1:27 pm, Paul Hanson
wrote:
At 14:48 17 May 2007, Bill Daniels wrote:

Hi Matt,

You probably don't want to hear this, but it is
my opinion and I'm sure everyone else with surge brakes
is going to hate me too, but here goes. GET RID
OF THE SURGE BRAKES. Replace them with electric ones,
with a GOOD

brake controller like a Tekonsha

Prodigy or an equivalent.

This is the same advice I have heard from several trailer
shops. They said
they don't even sell surge brakes anymore because of
customer complaints.
The replacement involves a new axle with electric brakes
and the tow vehicle
controller. I'd guess about $1200.

Bill Daniels

Thanks for backing me up on this Bill, you are actually
the one that got me on the electric brake kick (although
you probably don't remember) while I was visiting Sean
in 2005 with Towing my Sisu back from Elmira to Ca.
Thanks for turning me on to this setup, prices are
a bit cheaper than you think though. ;-)

Here is a link to a good online trailer parts supplier,
to give everybody an idea of prices, which does come
out to to around $600 on average, without even ebaying
or buying used which could obviously save even more.

http://www.easternmarine.com/em_store/trailerbrakes/

Recommended parts needed a
Two 10 inch drums at around $70 apiece----------------$140
10 inch Left/right hand brake assy's at $40 each---------$80
Axle at $140(add $20 for the welding of spring mounts--$160
Good controller at (DrawTite IntelliStop is equivalent
to Tekonsha Prodigy, top of the line and key to function)$140
Breakaway kit -----------------------------------------------$40
Tie plate kit -------------------------------------------------$20

Total for parts ----------------------------------------------$580

I chose the 10 inch Dexter brakes rated for up to 3500#
(as opposed to the wimpy looking 7 inch 2000# setup,
which should also work) as well as the 3500# axle.
My original axle was straight and mounted on top of
my leaf springs, so I switched to a drop axle mounted
under the springs, which gave my suspension 2 full
extra inches of travel without changing the overall
hight of my trailer (and the frame had been bent where
the old axle bottomed out into the frame, courtesy
of the previous owners ), which has the advantage of
lowering the trailer's riding C of G, making it even
more stable. Very user friendly and robust, at a cost
of $600ish after wiring. Individual installations may
vary, but this setup would work for many, and variations
on it should not cost much more. Use this as a reference
to price out local options, and skip paying shipping
while supporting the locals, unless local taxes are
excessive.

There is a more expensive and exotic option I failed
to mention earlier, there are electrically driven hydraulic
setups (called electric over hydraulic) which gives
you the mastery of control and breakaway safety the
normal electric setup offers, while keeping your hydraulic
system basically intact. It is much more expensive,
(to setup if you have no brakes already, but comparable
in price if you compare converting existing hydraulic
setups vs replacing everything to run electric), heavy,
harder to install, and space/energy consuming but CAN
be done as an option. I'm sure some of you out there
are very attached to your hydraulic disc brakes and
such, and this might be a more suitable option for
you. I am more opposed to the surge mechanism for controlling
the braking, not the hydraulic actuation, although
pure electrics are easier to maintain long term with
less moving parts.

Again, if anyone wants specific help to set up their
personal trailer, I would be more than happy to assist.

Paul Hanson
"Do the usual, unusually well"--Len Niemi

Another supplier in several regions.

http://www.redneck-trailer.com/

Electric brakes have several advantages, and one big disadvantage.

As an occasional transporter and retriever of gliders other than my
own, electric brakes are normally useful only on the owner's tow
vehicle, thus useless on most others. That's fine as long as it's
understood.

IMVHO, you may not make it safely over I-70 (and some other passes) in
Colorado and several other western mountain passes without engine
braking with glider and trailer in tow.

Any trailer braking system needs to be well maintained, tested, and
checked in use.

Frank Whiteley

I can confirm that the cobra surge brake on our trailer was engaged
during a long steep decent. This was on the road from cloudcroft down
to alamagordo. Didn't cause any problem, but the brakes were definitely
hot at the bottom.