master cyl pressure switch problem, help
Thread Starter
Instructor
Joined: May 2005
Posts: 132
Likes: 0
From: Torrington CT
master cyl pressure switch problem, help
just replaced the master cyl on my 85 because i found fluid leaking between it and the booster. When I took out the pressure switch that moniters front and rear pressure it was all corroded so I went to GM and got a new one. Bled out the brakes and found fluid leaking out of the new switch. Up out of center right where electric plug connects. Took it back to GM and they ordered a new one. Problem is the 2d switch does the same thing. Anyone have any idea whats going on. Brakes bleed out but as you pump them you get air. I put a 12 mm plug in place of the switch and they bleed out fine.
Thanks
Thanks
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Several years ago I had to replace my master cylinder on my 87. First rebuilt had the same problem yours has. Second rebuilt did the same. I bought a new GM master cylinder and that pressure differential switch has not leaked since. I recommend you buy a brand new master cylinder.
