drahgon55

I have a 91 honda crx dx. for some reason the brakes engage themselves without assistance from the driver and the only way to get them to release is to either release the pressure from the system by bleeding a little or shutting down the engine and them pumping the brakes till they get hard and letting the car sit for about 10 to 20 minutes. during the time the brakes are engaged i have had the car lifted and all 4 wheels are locked completly and the longer i go without releasing pressure in the system the harder the brakes engage to the point where i cant even drive the car and the car can be on a 60 degree hill in neutral(manuel transmission by the way) and not roll at all. i have changed just about everything in the brake system. here is all the things replaced. 2 front calpiers, 2 rotors and all pads, 2 rear brake cylinders, 2drums, 2 sets of hardware and all shoes, 2 front brake hoses, power booster, master cylinder twice, proportioning valve(used from a civic in the junkyard). Also the metal brake line in going to the right back wheel was severed and has a compression union(however that seems not to be the problem since that wheel bleeds easily). Also all 4 tires bleed easily.

i have brought this car to numerous shops many times and no one seems to know how to fix this problem anyone have any ideas.

drahgon55

no one has ANY ideas???

ChrisS

I would look at the brake power booster. (since the problem locks up all 4 wheels)

Are the mechanical connections between the power booster & the master cylinder, and the brake pedal & the power booster adjusted correctly?

drahgon55

well i replaced the power booster to no avail. all the connections seem to work well. the check valve is fine.

ChrisS

Assuming you don't have anti-lock brakes,

The factory manual for the 88 CRX (you can find it online) is very specific on:
-Pushrod Clearance Adjustment, page 13-25 (that the gap between the booster and the master cylinder)
-Pushrod Adjustment, page 13-24 (provides the correct pushrod length to connect the brake pedal to the booster)

It sounds like one or both of these is not adjusted correctly (which might be putting pressure on the brakes without your foot being on the brake pedal; maybe, there's some kind of positive feedback loop that makes the problem worse as you hit/release the brake pedal)

If all else fails, call your local honda dealership and talk to one of their technical assistance people.

drahgon55

hmmm i do have a manuel for my car i will check those clearences that is a good idea.

mn__30

To me it sounds like your brake fluid got contaminated. Check the fluid. And if it is contaminated you would need to change the master cyclinder and all the seals in the brake calipers and wheel cyclinders. Thats only if the system was contaminated. And don't forget to flush the system out.

onegreedy

this guy is correct, it sounds like your push rod is out of adjustment, probly putting a little pressure on the master cylinder then when you press the brakes and release they do not release and slowly get tighter and tighter
it could also be the master cylinder not allowing the fluid to flow back into the unit(1 way flow on brakes bad )

drahgon55

Well i think chris was right that it is the pushrod not adjusted properly. I went to my machanic today and told him to bring the pushrod in and instantly the brakes felt better and I drove the car for like 2 hours testing the crap out of it. I still feel the brakes engaging but it is soooooo much better than it was before i had the pushrod adjusted. before the car would not even roll on hills but today even when i felt the brakes pullin kinda hard the car still rolled decently. So im going to have my machanic pull the rod in further and keep testing it tomorrow since i am not working and i think that should solve my problem. Ill keep u posted on how it goes. but thanks everyone for all the help so far.

and it couldnt be the master cylinder because i had changed it twice already.

drahgon55

ok well my problem is solved finally. it actually wasnt even the pushrod. the problem was simply a spacer between master cylinder and the power booster. crazy huh. thanks everyone for your help.