Posted by MoparNorm on Monday, December 27, 2004 at 5:08PM :
In Reply to: Master cylinder push rod too long? posted by chris case on Monday, December 27, 2004 at 4:39PM :
Exactly, a too long actuating rod, or a wrong master cylinder piston or missing/broken/weak spring can cause the piston to move past the fluid ports in the chamber, once fluid is behind the piston it cannot return, acting in effect as a poor man's hydro-lock. Over time the fluid leaks back past and the brakes act normal for one or two stops. Was a 'generic' kit used or were the brakes re-built by someone else?
I'd adjust the rod back at least 1/4" away to start with to see if that has any impact (be aware that you will not have full braking at this adjustment! This is a TEST ONLY setting!)on the locking condition. If it does you can adjust it back towards the correct setting. You may also have a torn piston cup that is letting fluid past, or a scored or an out of round cylinder chamber. This is one reason that folks get their master cylinders re-sleeved. I made a miniture engine honing set-up for my master to properly re-bored the cylinder.
MN
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