Brakes - Master Cylinder


Topics covered:

Fault Diagnosis

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From: Richard Hills[SMTP:rhills@nmsu.edu]
Sent: Monday, July 24, 2000 8:37 AM
Subject: Re: [D90] brakes

> Hey guys, good morning. In the last few weeks (before I embarked on replacing
> my brake flex lines)I noticed that my brakes were losing a little bit of their
> power on the road, and after only a few hundred yards of driving off-road they
> became almost completely useless. I could press the brake pedal all the way
> to the floor with minimal response, yet could regain braking power by pumping
> the pedal a few times.
>
> After I replaced my flex lines, I bled the lines and topped the fluid off, yet
> the problem persists. Brake pads are also in good shape. So, given no leaks
> (that I can see) and a fully bled system, what might be the problem? It seems
> peculiar that almost immediately after driving down a bouncy road the brakes
> would transform from being a little weak to non-existent. Could it be the
> master cylinder going???

Farvin,
Something similar happened to me. In my case, I developed enough play in the front wheel bearings (I only noticed this off-road - on very low speed trails) that the resulting wobble in the disks would push the pistons out. The disks run very close and any movement will be felt.. After a pump or two, everything would be back to normal.

Rich Hills

(Wheel bearings turned out to be the problem - ed.)

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Brake Fluid

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From: Perrone T. Ford[SMTP:ford_p@nettally.com]
Sent: Tuesday, October 10, 2000 12:02 PM
Subject: Re: [D90] Castrol Brake Fluid

For those of you interested in why I am spending all this time looking at brake fluids (notwithstanding its one of the biggest pieces of the biggest safety system in your car), I believe in upgrading ALL the systems in my car if its economically feasible and if things need to be replaced anyway. With those upgrades come certain drawbacks, but those can be minimized if your are careful.

You might be interested in:

http://www.dougrippie.com/drm/brake_components.htm#Performance Friction's Z-Rated Brake Fluid

That site has a chart that compares the different brake fluids that are commonly available.

http://www.rennsportsystems.com/~porsche/2c.html

That is a porsche site that has some of the same info, but also has a generic guide for getting the most out of your braking system

http://www.olympiakos.com/svt-faq/node19.html

There is an EXCELLENT article here talking about the benefits and negatives of the different brake fluids...

Have fun!
-P

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Brake Bleeding

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From: Perrone T. Ford[SMTP:ford_p@nettally.com]
Sent: Wednesday, October 18, 2000 8:57 AM
Subject: Re: Brake Bleeding

Here you go!
(link to Motive Products Pressure Bleeder)
http://www.motiveproducts.com/

I don't know if you saw, but I used it on the BMW last night. ROCK hard brakes first time out. Remember, I have NEVER done this before (as evidenced by my 11th hour dash to Lowe's to buy a damn wrench small enough to fit the bleeder valve!) and even I thought it was simple. The unit is of very high quality and I thoroughly recommend it..........

-Perrone Ford

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