edjack
Joined: 04 Feb 2002 Posts: 3887 Location: San Jose, CA
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Posted: Mon Aug 20, 2001 9:15 am Post subject: master cylinder bleeding and bleed procedure-e12 |
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If you have not replaced the master cyliner, and it is full of fluid, you do not need to specifically bleed it. If you did replace it, you'll need to bleed it at the bleed screws, one at a time. If you use the brake pedal to pump the fluid, you need to open the screw, depress the pedal, and close the screw. Then slowly release the brake pedal in about 3-5 seconds time.
You would keep doing this until fresh fluid comes out. You would use a hose and a clear bottle to catch the fluid to observe this.
There is a downside to this method: if there is a ridge worn into the wall of the master cylinder, due to normal operation, the movement of the seals past this ridge will damage them. Note that the master cylinder will be stroking all the way to "bottom", which does not happen in normal operation.
However, I have never personally had this happen to me.
During this procedure, keep the master cylinder full of fluid. (I recommend Castrol LMA.) If it runs dry, you'll have to begin all over again.
Before you begin, use a turkey baster to suck out all the old fluid from the reservoir.
Begin at the right rear wheel, do the same as above, then the left rear, then the right front, then the left front.
Don't forget the clutch circuit.
NOTE: Brake fluid can ruin the paint. If spilled on paint, wipe and wash immediately.
I urge you to buy the Chilton and Haynes books for your car. Haynes sells one for the 530/528, ISBN 0 85696 632 0. Distributed in the USA by Haynes, 861 Lawrence Dr, Newbury Park, CA.
The Chilton book, ISBN 0 8019 7941 2, covers all BMW models from 1970-88. Chilton is in Radnor, PA.
Both will give you more details on bleeding than I have room for here, and if you've never bled a brake system, you'll need plenty of good info to do it correctly. |
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