Brake problem. Please help!

[beatd]

hey guys i need your help again. my problem is the brake system. when i first start driving the brakes are fine but after a couple of minutes of driving the brake pedal starts to get rock hard and the front brakes start to lock up causing the steering wheel and the whole car to shake also the car slows down by itself. i took my car to pep boys and they said that it could be the brake booster. does it sound right? anybody here have a DIY how to replace the brake booster? i couldn't find it.

ps when i checked under the hood the brake booster and brake cylinder was super hot. i removed the heat shield when i swapped the engine do you think the heat is causing the booster to malfunction? please help thanks!

[AmoebAssassin]

Moved to tires/wheels/brakes/suspension.

[beatd]

thank you sorry about that i just need help bad!! BUMP!

[yokota180sx]

Bleed your whole systemPut all New DOT4 fluid inBleed it again to make sure al lhte DOT3 **** it out

THen try itIf its still bad, change your brake cylinder **** stuff

[beatd]

why would changing the fluid help? my primary question is will the heat from the exhaust manifold cause the brake master cylinder and booster to fail while driving?

[Hijacker]

It's possible that the heat from the manifold could cause the fluid in the MC to boil, but that typically means that the fluid looses it's hydrolic nature and can start to compress resulting in a sloppy pedal.

Old DOT3 fluid can cause a sloppy pedal as well. DOT3 can absorb water from the air and begin to lose it's hydrolic abilities. That's why you have to leave the bottle sealed up unless you're pouring.

I have been running without a heat shield on my SR mani for 3 years now with no braking issues.

From the sounds of it, I would double check your calipers to make sure one isn't seized up. Then I would consider pulling the MC and booster for replacement.

The booster is pretty easy to get out:1- take off brake MC2-remove 4 nuts from inside passenger cabin holding booster to the firewall and brake pedal3-pull it out

[beatd]

thanks for reply.. now that you mention the fluid going bad after being exposed to open air i did leave the fluid container uncapped for a long time while i was actually swapping the engine because the lid was broken. maybe i should flush the fluid and put whole new fluid in. after that if the problem still occurs i should replace the MC and brake booster. i know that the calipers are alright because i already took the car to a shop and they even said that i should replace the booster soon so i'll probably replace everything all at once.

[yokota180sx]

DOT4not DOT3remember

[Eikon]

Another very simple thing to check is the vacuum hose that goes from the manifold to the brake booster. It could be old and weak and no longer holding it's form. If that were the case, you could be loosing your vacuum pressure after a bit of driving. That would result in loss of braking for all four wheels. It should only cost a couple dollars for a new length of hose.. so you might as well do it to be sure.

[beatd]

DOT4not DOT3remember

i'll change it to dot 4 just to be safe.. but will a bad brake booster cause my brakes to lock up after driving for a couple of minutes? each day its a different side in front only.. i'm going to replace the brake booster, flush the brake lines and put dot 4, and MC tomorrow