master cylinder blues
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Joined: May 2007
Posts: 62
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From: scarborough maine
master cylinder blues
So i buy a new master cylinder...after waiting [B]12[B] days for the freakin thing to arrive, i find that two of the brake boosters bolts are crooked. after aligning and fitting it in the car, i begin to bench bleed the master cylinder, only to find the brake fluid leeks out of the piston rod thing after pushing it to get the bubbles out. My old one didn't even do this and it was bad. I guess the booster would stop this from leaking out when bolted together....but should i return this peice of sh*t? is a little brake fluid supposed to drip out when i plunge that thing?
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
A couple of things to check, or you might repeat the problem again.
First of all, the plunger MUST move concentric to the bore of the cylinder... that is, when you press your pedal, the rod must move through a line parallel to the bore.
If it moves through an arc into the bore, then it creates uneven pressure on the seal and it can/will leak.
If the master cylinder mounting has been modified for clearance issues, then you may have an alignment issue.
Also, make sure the pedal travel is correct. Do NOT over extend the travel!
If you depress the piston further than specification, the O-ring seal is compromised and you will get a leak.
First of all, the plunger MUST move concentric to the bore of the cylinder... that is, when you press your pedal, the rod must move through a line parallel to the bore.
If it moves through an arc into the bore, then it creates uneven pressure on the seal and it can/will leak.
If the master cylinder mounting has been modified for clearance issues, then you may have an alignment issue.
Also, make sure the pedal travel is correct. Do NOT over extend the travel!
If you depress the piston further than specification, the O-ring seal is compromised and you will get a leak.
