Posted by gmharris [72.219.148.98] on Saturday, August 09, 2014 at 15:39:51 :
In Reply to: 66' TWPW Brake Bleeding Problem posted by Bob Perry [107.5.248.120] on Saturday, August 09, 2014 at 14:24:30 :
If you keep getting air, the only place that could cause the problem is the master cylinder. Every other place downstream from the master cylinder is under pressure. Even if a leak downstream were to draw a little air in on the return stroke, I don't think it would cause "burping" and it probably wouldn't cause burping on both sides.
I'm sure you made sure that the reservoir feeding the rear circuit is filled. But, I would watch the reservoir while someone pumps and re-creates the problem.
Based upon the facts that you just changed the master cylinder, the brake system was working O.K. before the change, and the nature of the problem, I would say the master cylinder is at fault.
I'd try bleeding at the master cylinder and see what results you get. It's easy enough to rig a piece of plastic tubing with a fitting so the fluid recirculates back to the reservoir when you pump the pedal.
Sometimes, the new/rebuilt master cylinder comes with the fittings for bleeding and a piece of plastic tubing. I save these pieces for reuse with other master cylinders.
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