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R32 1989 Gtst Brake Problem

Mark32
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Mark32 Newbie

Mark32

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Posted

Hey everyone,

I was driving home today and all of a sudden my car started to pull back like the brake pedal was pressed but it wasn't.

I continued to drive till I could drive till it was safe to pull over.

I got out and checked the brakes and the front rotors were smoking on both sides and rear.

The pedal is hard to press and stays the same when car is off or running.

It has been sitting for half hour and now it's gone.

A month ago the same thing happened but not as bad and I thought it was low fuel so out more in and it was fine.

Does anyone have any idea what the problem is?

It doesn't happen all the time.

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GTSBoy Grand Master

GTSBoy

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Posted (edited)

You either have sticking pistons in the calipers - unlikely if it is happening on both sides of the car - or you have a problem at the booster and/or master cylinder. Given that you say that there appears to be no assistance from the booster, it has probably failed, and has probably failed in more than one way. One failure results in lack of assistance, and the other failure (which might be caused by the first) is causing it to jam the master cylinder's pushrod in the "brakes on" position.

Get it to a brake workshop pronto before it kills you or someone else.

Edited by GTSBoy
Sinista32 Grand Master

Sinista32

Posted
Posted

I understand that if the peddle is hard when the car is not running and when it is running then you have a brake booster issue.

When you turn the car on the brake peddle should go down.

As you have been told it appears you have multiple issues. Booster, BMC and perhaps the pistons also.

Seriously, as advised take it into a mechanic.

Mark32 Newbie

Mark32

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  • Author
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Thanks everyone even the funny comments haha.

It has only happened twice and when I leave it for half hour it's all good again.

I don't think it would be piston because all brake calipers lock up, not just one.

I'm going to get another brake master cylinder and see how it goes.

Someone said it could be air in the master?

GTSBoy Grand Master

GTSBoy

Posted
Posted

Look, as I said earlier, if the booster is giving no boost, then something is wrong with it. That may simply be a vacuum supply problem. But it is also an old car and I know from personal experience that the boosters themselves fail when given enough time. Hell, I had to replace mine many years ago. So it is just as likely that there is a problem inside the booster. And given that your brakes are jamming on, it would seem more likely that the booster is buggered in some way that is interfering with the movement of the pushrod through it.

Mark32 Newbie

Mark32

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Look, as I said earlier, if the booster is giving no boost, then something is wrong with it. That may simply be a vacuum supply problem. But it is also an old car and I know from personal experience that the boosters themselves fail when given enough time. Hell, I had to replace mine many years ago. So it is just as likely that there is a problem inside the booster. And given that your brakes are jamming on, it would seem more likely that the booster is buggered in some way that is interfering with the movement of the pushrod through it.

I know buddy, I just have no glue when it comes to brake masters or booster.

Is there a way I can find out if it's the booster or if it's the master?

The vacuum line going to the booster isn't kinked or blocked. The fluid seems fine as it was flushed out before the car was put on the road a month ago.

All the brake lines are in good condition, calipers all seem good and the pads are new and rotors are fine.

Could it be that I boost my car and there is too much pressure going into the vacuum like into the booster?

Before they started locking up I have it a boot a block earlier?

GTSBoy Grand Master

GTSBoy

Posted
Posted

Well, yes, there is a one way valve that allows the engine to suck air out of the booster but not allow it to push boost in (and of course, it traps vacuum in the booster so you can use brakes even after you've had no manifold vacuum). If that valve fails then it will allow you to replace vacuum with boost, which would be a very bad thing. But, importantly, if you put boost into the booster, then you have the opposite of putting the brakes on - you have anti-braking. It shouldn't jam your brakes on.

The description of your problem makes it sound like much more than a simple check valve failure.

Given your self admitted "I have no idea about brake masters or boosters", please take it to someone to fix it.

D.I.Y. Mik Veteran

D.I.Y. Mik

Posted
Posted

Well if you are going to DIY, get the manual and have a look.

You can find it around here somewhere.

You better do a full inspection and service on the brakes, like the manual says to do, and make sure EVERYTHING is good.

Its not hard or expensive, and its worthwhile, because brakes are very important.

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