Master cylinder failure: symptoms?

[dochidalgo]

I've noted these:
* The brake fluid turns dark even been replaced with new one (complete)3 or 4 days after the procedure.....does that mean the rubber rings inside the master cylinder are worn out??
* The hard braking performance has been deteriorated as time goes by....

Do you recommend to replace (brand new or rebuilt) the whole master cylinder or just the rubber rings?

Thanks in advance for your info
dochidalgo

[ConElite]

How much fluid did you change when you said you replaced it. You should try bleeding your entire brake system. Run at least 2-4 resivoir's full. That should be enough to get all the old fluid out b/c if you only suck up whats in the res. and put new one in then some of the old fluid is going to go back in to the res. and turn it black. So get someone with a strong leg and get to pumping.

[dochidalgo]

Well, the brake shop drained the fluid with a vaccum pump, so i'm sure the old fluid was drained completely.
Discs, brake pads and booster are fine....

dochidalgo

[Thomas L. Parker]

Dark Fluid

Doc,

It sounds like the "O" rings are deteriorating. Also it sounds like the fluid in the system is contaminated. It would be easier to get a new master cylinder. After it is installed, flush the system at all four wheels until the fluid coming out is clear.

Brake performance can degrade for a number of reasons. If the flex hoses to the front disk caliper are wearing out they could be bulging and causing diminished performance. A visual inspection with someone pumping the brakes will make this easy to check out.

We would like to think that our cars will last forever but they are machines and they do wear out.

Good luck with the brakes,

Tom

[dochidalgo]

Tom
Glad to hear from you...thanks for your imput....I'm going to replace the master cylinder and the brake fluid as you recommend. How about the BMW or Motul brake fluid??

Sorry, I did not mention my car has installed steel braided brake lines all around, including the 5th one over the "pumpkin"....

And yes, time run faster than I'm aware....... like my TA wear out.... even myself!! Jesus...

Hope you and your family are fine
My very best regards
Dochidalgo