Brake fluid leak ?
Thread Starter
Instructor
Joined: Jun 2004
Posts: 162
Likes: 1
From: Johnsburg IL
Brake fluid leak ?
I recently completed a frame-off including all new brake lines, calipers and master. I seam to be chasing leaks, first the line from the master to the front side dist. block and now it leaks out of the top of the master. This only happens when the car is driven, won't leak until it is hot. I have lowered the fluid level to allow for heat expansion and bench bled the master.
Any thoughts shared greatly appreciated.
Any thoughts shared greatly appreciated.
Melting Slicks
Joined: Nov 2001
Posts: 2,668
Likes: 43
From: Eastern US XX
Originally Posted by colorado1967
I recently completed a frame-off including all new brake lines, calipers and master. I seam to be chasing leaks, first the line from the master to the front side dist. block and now it leaks out of the top of the master. This only happens when the car is driven, won't leak until it is hot. I have lowered the fluid level to allow for heat expansion and bench bled the master.
Any thoughts shared greatly appreciated.
Any thoughts shared greatly appreciated.
Thread Starter
Instructor
Joined: Jun 2004
Posts: 162
Likes: 1
From: Johnsburg IL
I used standard, not SS lines and now my problem has moved to the Master. When the car is cold, there is not leak from the top but as soon as it warms up while driving it starts leaking. The brake fluid is not helping the paint on the firewall at all!
Thanks
Thanks
Le Mans Master
Joined: Apr 1999
Posts: 6,134
Likes: 46
From: Raleigh North Carolina
The master is not meant to be filled to the top. Leave about 1/8-1/4" at the highest (rear) edge. The rubber gasket is removeable, and fluid can pool in it. I remove it, and clean it with brake parts cleaner, and re-install it when this happens. Getting the curly-cues reoriented can be tricky, but I pop them inside out and dry them thoroughly.
Thread Starter
Instructor
Joined: Jun 2004
Posts: 162
Likes: 1
From: Johnsburg IL
I lowered the level to 1/2" just to see if that was the issue and the Master still leaked so I know it is not the level unless my system is getting super hot. Could be caused by a bad adjust of the booster shaft? How do you adjust the shaft length?
Thanks
Thanks
Melting Slicks
Joined: May 1999
Posts: 2,897
Likes: 0
From: Moon Township PA
[QUOTE=colorado1967]I recently completed a frame-off including all new brake lines, calipers and master. I seam to be chasing leaks, first the line from the master to the front side dist. block and now it leaks out of the top of the master. This only happens when the car is driven, won't leak until it is hot. I have lowered the fluid level to allow for heat expansion and bench bled the master.
Any thoughts shared greatly appreciated.[/QUOTE
Have you tried a new master cylinder cap and gasket?
Any thoughts shared greatly appreciated.[/QUOTE
Have you tried a new master cylinder cap and gasket?
Le Mans Master
Joined: Apr 1999
Posts: 6,134
Likes: 46
From: Raleigh North Carolina
Originally Posted by colorado1967
I lowered the level to 1/2" just to see if that was the issue and the Master still leaked so I know it is not the level unless my system is getting super hot. Could be caused by a bad adjust of the booster shaft? How do you adjust the shaft length?
Thanks
Thanks
I have run across rebuilt units with the wrong cap installed... they also leaked. There are a few caps that look nearly identical to the correct cap, but are not. They are off just enough to leak.
If it's leaking between the M/C and the booster/firewall, then the M/C is bad.
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Thread Starter
Instructor
Joined: Jun 2004
Posts: 162
Likes: 1
From: Johnsburg IL
The master cylinder is new and may have been overfilled but since corrected. I have also tried a second new lid.
My brother said the brake system could be getting to hot from possible stuck caliper or the booster shaft being to far out. He thought the extra drag could be creating more fluid expansion than normal. I have confirmed caliper ok but not sure how to properly adjust booster shaft.
Thanks for all the responses.
My brother said the brake system could be getting to hot from possible stuck caliper or the booster shaft being to far out. He thought the extra drag could be creating more fluid expansion than normal. I have confirmed caliper ok but not sure how to properly adjust booster shaft.
Thanks for all the responses.