Hey guys i had a quick question about the brakes. When i push on the brakes on the brakes the car stops but the brakes lose pressure until im on the floor. This also happends when im a stop. What im planning to do is im going the bleed the system and see if that helps my problem. My question is, is there anything else i should check or anything else that could be my problem. Im not lossing any brake fluid i made sure of that. I have an s4 87 gxl. about a 134k miles. Any help would be greatly appreciated.

 

yes bleed them and also check the booster to make sure its working correct.
this is done by, when the car is off pump the brakes till the peddle gets firm, then start the engine while still holding the brakes. if it softens up then the booster is working. if not then its a dead booster. i dont know any other test for the booster but thats what i suspect.

 

ss brake lines... my pedal travel is alot less than stock, and i have only done the front so far.. to lazy to do the rears....

not saying that is 100% your problem, but it should help

 

What you've got sounds like a problem I had a while back. If you jam real hard on the pedal is it stiff, but a light press lets it sink, and you're not losing fluid anywhere? That's bad seals in the master cylinder, so a soft press allows the fluid to go around, but a hard jam sort of flares the seals and they do their job. Solution is to get a new MC, they're not that expensive, worth it over messing around rebuilding one IMO. Make sure to follow the bench bleeding instructions when you install it.

 

Thanks for the info i will do the booster test tomorrow. Just trying to look a few steps a head, i see mazdatrix sells the master cylinder but not the booster, i found a few on basic sights like wholesalers and even autozone and advance auto parts, but im sure i can trust they send me the right part. any suggestion on good place to look for one.