Brake Servo, is there an Alternative.

[robinspain]

Having got home , (thanks for the help about the gas cap) the brakes were a real problem i.e very heavy and hard to stop but not spongy. Have taken the servo pipe off and it sucks like a typoon so no problem there. The pedal dose not depress when started so the servo looks like the culprit. Is there a direct replament that is eaiser to get hold of than the Opel GT one (ok cheaper). Also the previous owner has put a new pipe on but no valve is this likly to be problem. Also for the experts there is a large black plastic tank with a single spiget sticking out, this is down near the batery. Was this an extra vacume tank? it is no longer atached to anything. Any thoughts apreciated.

Cheers
Rob

[BQS4]

There's another possibility, the front rubber brake lines could have collapsed, you might want to check them first, especially if the car has/had been sitting a while.

[David McCollam]

If there is a problem with the brake servo, the car will die when you press the brake pedal. The most likely problem is the plastic check valve in the brake vaccuum line is in line backwards. This valve is between the brake servo and the intake vacuum port. See attached photo of Manta. GT is identical except for location of servo and master cylinder. Black portion of valve should be on intake side and white portion should be on servo side.

Gene is also correct in that the brake line internal structure may be collapsing. I would check the brake vacuum check valve first. The black canister in the front of the engine compartment is a fuel tank vapor canister to help absorb fuel fumes from the gas tank. It originally had a vacuum source from the air cleaner and pulled fuel vapors off a line from the fuel filter.

Good luck,

Dave

[GTJIM]

Originally Posted by robinspain . Also for the experts there is a large black plastic tank with a single spiget sticking out, this is down near the batery. Was this an extra vacume tank? it is no longer atached to anything. Any thoughts apreciated. Cheers Rob

That black tank is far more likely to be a part of the fuel tank vent system - the carbon filter that catches petrol fumes from the tank vent lines and recycles them through a carb vacuum port. Check to see if the tank vent lines are there but not hooked up to it - without them you get strong fuel smells inside the car.

As for the entirely separate brake booster vacuum line, it should have a oneway valve in it to stop backfires bursting the diaphram inside the booster.
If the booster assembly has an 'ATE' brand tag on it a rebuild kit should be available from any half-way decent Brake Shop as that is a continental made brand also fitted to BMWs and other European cars - not the same booster but the same internal size and parts for some of them.

[robinspain]

Thanks for the advice. I will check the hoses, but it looks at first glance that someone has already gone down this route. I will also fit a valve (and put it in the right way round). As for the canister, there are a number of pipes missing or just cut off, it looks like some on has tried to dismantle the emmisions control. Interestingly the car does smell of petrol so I guess I can add this to the growing list of things to sort out!!!!!
Can't do anything for the next couple of weeks but I will post, hopefully my findings on the brakes in the hope that it may help others. Thanks again guys for your advice.

Cheers Rob

[robinspain]

Just picking up on Daves helpful reply. Having finally got some petrol (the cap problem) The car would stall every time I finally came to a halt pushin VERY hard on the brakes. I put this down to the Carb (Project No;2. Get the car to stop is first priority) which would speed up when the clutch was depressed and then slow right down to nothing. So it looks like the servo. Again will keep you updated of the final solution.

Cheers
Rob