Brake Bleeding Problem - '82 Rabbitt Diesel

Mar 27, 2005 2 Replies

When the brake pedal on this car started going to the floor, I looked for signs of leaking brake fluid and leaks on any of the brake lines or wheel cylinders. I found none and the brake fluid reservoir which sits atop the master cylinder was at it's full mark. I suspected that the master cylinder was shot.



So I put a new master cylinder in. However, when I went to bleed each wheel (starting at the farthest away), I found that I could not get the air bubbles to stop coming from the right rear cylinder. The other three are clear with no air upon bleeding. The rear brakes including cylinders were replaced a year ago and are in good condition (dry under the rubbers).



This car does not have the "equalizer" that is mentioned in some manuals.



I suspect that it might be a problem with the connections of the brake lines to the master cylinder. However, it doesn't seem to be leaking fluid in any way. And I still get air bubbles from the bleeding of only the right rear cylinder. Could the new master cylinder be defective?



So my question is: What have I done wrong here? or What could be the source of the air in the bleeding of the right rear cylinder?



Thanks for your advice. Wray


I'm no mechanic, but I've found that wheel cylinders are more likely to fail than a master cylinder I guess because wheel cylinders are exposed to wheel (braking) heat. And wheel cylinders fail in one of two ways: (1) they leak brake fluid -- this is the most visible type of failure, and (2) they leak, but instead of brake fluid leaking out of the system, they draw air into the system when the brake pedal is released to is resting position. Both cases cause make it impossible to bleed the system without replacing the wheel cylinder.

Good luck!

Jim

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