3-Series (E21, E30)Chat relating to the BMW 3-Series from 1975-1983 and 1984-1991 line. Specific models: BMW 315, BMW 316, BMW 318, BMW 318i, BMW 320/4, BMW 320i, BMW 320/6, BMW 323i, BMW 320i. E30 Family models include: BMW 325e, BMW 325i, BMW 325is, BMW 325ix.
for the past few weeks something was messed up with my brakes and still is messed up. when i stop at a red light or just stop period, the pedal starts to get soft and the car starts to roll, so i have to press even harder and deeper on the pedal, then a few seconds later the pedal gets soft and the car rolls again, before you know it i am pressing allll the way on the pedal just to keep the car from rolling. im not sure what the problem is the car is full of brake fluid. my dad said it might be the rear wheel cylindar cuase he said when i press the pedal it leaks a lil bit.
im totaly lost right now if any one can help thanks!
sounds like you master cylinder is shoot! i would not be driving that car if i where you.
do you know what the master cylinder is? it is a hydraulic piston that sends the pressure to your brake cylinders. thier is a ruber like ring that makes the master cylinder fluid tight, sounds like the plunger in the cylinder is shoot and that it is letting fluid travel around it. hence it is not kepping constant pressure on your brake cylinders.
another option besides that is a rubber hose that is about to bust and is swelling up greatly (with brake fluid). ( i still belive that it is the master cylinder though), but this could be the problem also. ( i assume that BMWS had a rubber section of brake hose somwhere?)
i dont know the $$$ of fixing this on a bmw, but it is a fairly easy project that you can do your self. should not cost more than $100.
definately your master cylinder. w/o question replace it soon. Its very simple, you can do it yourself, and it like supahaole said, it will should be less than 100 bucks. i replaced both my brake and clutch master cylinders and my clutch slave cylinder all in one day before...so its really no biggy.
If your rear wheel cylinders are leaking, they will cover your shoes in fluid. If you stop medium-hard to hard, the fluid will instantly boil and cause the brakes to lock up. This can be VERY dangerous, especially if you happen to be in a turn and it happened. fix it as soon as you can...and after you replace the wheel cylinders, if the shoes did get saturated with brake fluid you have to raplace them too. You can not clean the fluid off them and even tho new fluid is not leaking out, the shoes can still lock up like described earlier.
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