Master cylinder issues
Thread Starter
Racer
Joined: Feb 2005
Posts: 338
Likes: 49
From: Quincy,Illinois
Master cylinder issues
I need some help with a master cylinder problem.
I recently installed a DRM bias spring in my 86 track car. During the second weekend of running I noticed a leak and discovered it was leaking thru the hollow brass connector pins in the pressure switch. Thinking I had nicked an o-ring on the bias piston when re-installing, I got another rebuilt master cylinder and installed the new bias spring before bench bleeding. While bench bleeding it started to leak thru the pressure switch again.
Should fluid be getting past the orings and to the port where the pressure switch is? Is the switch suppose to be able to hold back fluid pressure? Not really sure how the proportioning piston actually works. Anyone know????
I recently installed a DRM bias spring in my 86 track car. During the second weekend of running I noticed a leak and discovered it was leaking thru the hollow brass connector pins in the pressure switch. Thinking I had nicked an o-ring on the bias piston when re-installing, I got another rebuilt master cylinder and installed the new bias spring before bench bleeding. While bench bleeding it started to leak thru the pressure switch again.
Should fluid be getting past the orings and to the port where the pressure switch is? Is the switch suppose to be able to hold back fluid pressure? Not really sure how the proportioning piston actually works. Anyone know????
Thread Starter
Racer
Joined: Feb 2005
Posts: 338
Likes: 49
From: Quincy,Illinois
This is the second master cylinder I have used for this. I was very careful re-installing the bias piston. I don't think I nicked an oring.
Anyone else change their bias spring and have any issues? Success or failures???
Anyone else change their bias spring and have any issues? Success or failures???
Racer
Joined: May 1999
Posts: 290
Likes: 0
From: Nashville TN
You may just be unfortunate enough to have a poorly remanfactured MC. I had purchased a reman unit for my car through a local parts house and discovered it leaked right out of the box while I was trying to bleed it (before installing the DRM spring!). It was leaking from here though:
I boxed it back up and returned it. Got my original core back, installed the DRM spring in it, and has been good since (another story as to why I thought I needed to replace my MC in the first place).
Seems unlikely that both of the MCs you've used would leak from the same place, but it's possible.
Good luck!
Thread Starter
Racer
Joined: Feb 2005
Posts: 338
Likes: 49
From: Quincy,Illinois
One thing I noticed is that the proportioning piston was forward as far as possible against the screw in plug when it was leaking. I pushed it back about a 1/16" so the groove was lined up with the hole for the pressure switch. It seemed like it didn't leak anymore while I was bleeding. I am going to install it and try it out. Hope it doesn't leak......
Not sure if this could have caused the original problem, but I was autocrossing the car and the booster was going bad. It finally gave up completely the last day and I was having to stand on the pedal all the time extremely hard to slow the car down.
Could that have caused the proportioning valve to move in the bore and cause it to leak out past the pressure switch ??????
Not sure if this could have caused the original problem, but I was autocrossing the car and the booster was going bad. It finally gave up completely the last day and I was having to stand on the pedal all the time extremely hard to slow the car down.
Could that have caused the proportioning valve to move in the bore and cause it to leak out past the pressure switch ??????
