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Opeler
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343 Posts
Discussion Starter · #1 · (Edited)
Thanks for your help with my earlier post regarding my brake pedal not returning which between us all looked like it was due to the return spring on the brake pedal. Replaced it with a stronger spring which seemed to ease the problem.....that was until I was driving on Sunday and the pedal went like rock!!!

Been a will since I had to use 2 feet on the brake to stop the car!!!

Well it seem that all my problems are pointing to the brake booster or Servo as it is know in the UK. Heres what happens:

1. Brake pedal slow to return fully
2. Rock hard Brake pedal
3. Car when at idle increased in revs when I press the brake pedal (MAD!!)
4. Removed the valve from the Servo/Booster and I thought that it should be a one way flow valve, but it is not
5. Have replaced the servo hose (not with the correct reinforced pipe, but it made no difference, so I assume that this is not at fault)

Just wanted some comformation whether it is reparable or scrap and/or if anyone has had these similar experiences.

Cheers

Matt
 

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Member
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247 Posts
That sounds scary for sure. From your description I would suspect the power booster has a leak. On a car with a brake booster if the booster fails the pedal will get VERY hard and the car will not respond to normal pedal pressure. Also if their is a tear or a hole in the booster diaphram this could cause a large vaccuume leak, engine RPM will increase. Their is, should be a one way check valve, either in the connection at the booster or in the vac. line going to the booster. On my Manta it is in the Vac. hose. Also the valve must be installed in the right direction, so as to hold Vac. in the booster during periods of low engine Vac. I would try a booste replacement.

DAN
 

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Detritus Maximus
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3,105 Posts
The boosters are repairable. I had mine rebuilt for $115 or so at Vanco in Ca. I'm sure there are places in the UK that can do it. It will probably be even cheaper over there. It sounds like you may have small tear in the diaphragm or the valve inside the booster is stuck. The valve in mine went bad, but with the opposite effect, I'd start the car and the pedal would sink to the floor. This is without me touching the pedal! It was really weird to see it move by itself and lock up my brakes.
 

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Opeler
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343 Posts
Discussion Starter · #4 ·
It actually transpired that the diaphram in the servo/booster has swollen which was what was making the brake pedel not return. This was due to missing or faulty vacume valve. The booster then sucked in the gasses from the manifold.

This then split the rubber diaphram which caused the stiff pedal and revs when depressing the pedal.

Can anyone tell me where the non return valve is. I thought it was held withing the plastic elbow that attaches directly onto the booster. Mine has nothing inside it!! (it may have been sucked inwards into the booster) Am I missing the valve, I do not have any other device between the booster and the manifold!


Ta

Matt
 

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Registered
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1,127 Posts
Check with Gil at Opel Source in California for a new valve and I would advise getting the booster replaced with a re-built or a new one. Don't put a used one in as this is just inviting another problem later as you don't know how used it is.
 

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'69 GT- Guards Red
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26 Posts
I bought a new hose and valve (the old hose did not have a valve) from OGTS (they were actually out of new valve so they sold me a "good" used one for $5). My question is exactly where (factory location), along the hose, is the valve instaleed and which direction does the arrow point?
 

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boomerang opeler
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5,648 Posts
hey matt were are you in uk
i drive up and down from the sunny north east of "mackam land "to plymouth and points west all year i have a spare servo if you need it
or if im not going your way theres allways snail mail
the valve goes app. mid way between servo & manifold and stops air returning to manifold
 

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Propmark said:
I bought a new hose and valve, the removed hose did not have a valve, from OGTS (they were actually are out of new valve so they sold me a "good" used one for $5). My question is exactly where (factory location) along the hose is the valve installed and which direction does the arrow point?
I can't help you as far a location as my GT came without one anywhere. I just cut the hose close to the booster and installed. The arrow must face away from the booster and point toward the carb. Hope this helps
 
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