Problem with brakes.

Hi All:
Recently whenever i stop at a traffic light my brake pedal slowly depress to all the way to the floor. While driving in don't have to pump the brake pedal to engage the brake. Secondly yesterday my rear right brakes got jammed and i could smell the burning of brake shoes.
So this morning i went to my mechanic and he suggested replacing the master cylinder to fix the first problem and replace the caliper hose to fix rear brake issue, besides now i have to get new rear brake pads.
Please note when mechanic removed the wheel i didn't see any oil nor there is any brake fluid leak under master cylinder area.
What do you guys suggest?

Im not sure about the master cylinder problem. I do know that an older caliper hose can cause your brakes to stick. One night I did a burnout in my car and after that it was pulling really bad to one side. I could smell the pads burning when I got home and the flex line was all clogged up and wasnt letting the pressure back out of the caliper.

If you have discs in the rear, check to make sure your caliper pins are free to slide. A sticky caliper pin can give you that type of problem.

you won't see any fluid leak at the wheel from a clogged brake line/hose. the clog keeps the fluid from returning/releasing so the caliper keeps the pads applied. (and i'd second looking at the caliper sliding surfaces to make sure what the cause of the non-return is)

you may or may not see a fluid leak at the master cylinder. they can 'leak' internally, so pressure pushes through internal seals. if it's leaking out the bore/rod seal at the back of the master cylinder, the fluid will go into the brake booster and you may see some weeping at the master cylinder/brake booster mating surfaces, or you may see some leaking inside the vehicle -- look up at where the brake pedal connects to the master cylinder push rod, sometimes you will see/feel brake fluid up there when that seal leaks.
edit add: are you using brake fluid?

the brake pedal depressing all the way to the floor at a stop (and not when you are driving) sounds more like it could be a leak in the vacuum assist system rather than in the hydraulic system. but the more i think about it, probably not, because a vacuum leak ought to make the pedal harder without the vacuum assist, but.......edit add: are you experiencing any symptoms of a vacuum leak?

what happens when you sit there with the engine *off* and step on the pedal ? does it behave the same as when the engine is running?



hth

//bc

edit add: are you experiencing any symptoms of a vacuum leak?
Sometimes i can hear a popping sound from front around master cylinder area.
Brake fluid is at max.

ok, do the pedal test with the engine off. i'm rethinking the vacuum leak idea, but it is still a possibility. the fact you are not losing fluid -- it can still be the master cylinder.

if car is off then pedal is stays stiff, or it can't be pressed.

It still sounds like the master cylinder is bypassing internally. You can have a hard brake pedal that doesn't drop, but just let off a little bit, then press again and it could go down. Seen that happen before. Pressing harder helps the cups inside the master cylinder to seal better, then, letting off weakens the seal and the pedal drops.

Update:
Replaced master cylinder and rear right caliper hose. Problem fixed.

Thanks - glad you got it!

Update:
Replaced master cylinder and rear right caliper hose. Problem fixed.


How much did it cost if you don't mind me asking?

I have the same problem except my brakes are not working at all an pedal goes to the bottom like nothing and i had smoke all over by the time i made it home. It was like a 5 blok drive.

Thanks

I am having a brake issue with my 91 rodeo.She still stops,but the pedal goes to the floor.My rr anti lock light comes on.The fluid is full and I don't see any leaks anywhere.What do I do?

you need to start a new post.this one is from 3/07

I am having a brake issue with my 91 rodeo.She still stops,but the pedal goes to the floor.My rr anti lock light comes on.The fluid is full and I don't see any leaks anywhere.What do I do?


A master cylinder can still be bad without an external leak. The cylinder leaks internally around the piston seals.