so im driving down the road in my 89 5speed turbo and not even touching the breaks and the front tires lock up. any sugestions? ive replaced the calipers pads hoses lines and even tried the abs but still does it.
sticking brakes
- Thread starter harojake
- Start date
when i pulled off that valve there was no pressure on the engin side but the booster side sucked in a bunch of air when i pulled it off, is that normal? should i try a new one?
I had a similar problem, but it was all 4 brakes. I want to say the main culprit was the brake cylinder, though I had a few other problems like bad calipers too.
I replaced the brake cylinder, bled the system, and replaced that uhh... 'valve' that goes from the intake manifold to the booster. No problems after that.
I replaced the brake cylinder, bled the system, and replaced that uhh... 'valve' that goes from the intake manifold to the booster. No problems after that.
I am having the same problem but only when it is hot outside. The pedal had pressure like I am applying the brakes. I have replaced the calipers and it still does it. Don't know what it could be maybe the brake booster. Any advise?
The one way valve is only there to keep vacuum on the booster when there is low engine vacuum. Sounds like a back flow problem in the master. A bad booster will just give you a hard pedal. Also the check valve should have no vacuum on the engine side but keep vacuum on the booster side when the car is off. This is so if you engine dies you have a few times to press the pedal to stop before the booster uses all the vacuum, also make it so the brakes work under boost conditions, or low vacuum in general. Try going up a hill and pressing the brakes a few times under load you will bleed off the vacuum in the booster and the pedal will be hard to press until you let off the gas and let the booster get vacuum back.
OneJArpus;1608351 said:
That is what I was going to say. He did everything but what makes them stick. Also, your ABS isn't working if you lock up about 5-6 mph.
Turbo or non turbo doesn't matter, under load vacuum decreases so the booster will not work as well. Its most likely gonna be the master cyl not releasing if they are just sticking after letting off the brake. This can be tested by loosening the bleeder valves to release the pressure on the calipers and try to drive it without hitting the brake to see if they still stick. If they are just sticking all the time its probably gonna be slide or the pad is jammed into the hardware (this can happen because of bad casting or painting on the pads, see it a lot).
So the question is, are they sticking all the time or only at a certain speed?
So the question is, are they sticking all the time or only at a certain speed?
How old is the brake master cylinder? I had a similar issue once, with the rear wheels, when I replaced the master w/a rebuilt one. If you still have the original or think that it's questionable, rebuild it. The rebuild will take you about 20-30 minutes and the kit only costs around ~$12.
If the calipers (slide pins or pistons) are sticking, the brakes might feel normal when cold, but when they heat up from dragging the pads will swell up and lock the brakes harder and harder as they get hotter and hotter.
Ohhh and also, try jacking your car up and seeing which wheels are locked up. Then see if opening the brake bleeder on that wheel frees up the brakes. If it does then you probably have a brake hose that's internally collapsed or clogged. I see it all the time. Second most common thing that locks the brakes (next to rusted slide pins).
Ohhh and also, try jacking your car up and seeing which wheels are locked up. Then see if opening the brake bleeder on that wheel frees up the brakes. If it does then you probably have a brake hose that's internally collapsed or clogged. I see it all the time. Second most common thing that locks the brakes (next to rusted slide pins).
metaphysico;1613354 said:
It happens when I am driving on a hot day only and after leaving a stop lite. The pedal has pressure and will not go away until I let the car sit for a bit like turn it off over night.
Master cylinder, I bet. If that does not resolve it, might be the brake booster. Sounds like either the insides of the master cylinder are sticky/stickin', or the diaphram in the booster is possibly leaking. If U don't want to buy the MC rebuild kit yet, you can open yours up and clean out any gunk, then re-apply some of the "lithium soap base glycol grease" as indicated on page BR-13 in the TRSM.
The troubleshooting matrix starts on page BR-2.
Good luck!
The troubleshooting matrix starts on page BR-2.
Good luck!
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