Posted by Keith in Washington [172.71.151.107] on Monday, March 25, 2024 at 12:46:46 :
In Reply to: Chevy Conversion Status - New CMC posted by Vaughn [172.69.140.144] on Sunday, March 24, 2024 at 16:52:44 :
Vaughn, Watch out!!!! I used that MC for my clutch also on my 327 conversion. They don't work. I had 3 of them fail in rapid succession. They blow fluid past the seals. They failed quickly for me and destroyed the paint on the fire wall. They apparently can't take the pressure. I also found that fluid quickly turns black which I believe to be the rubber seals failing via wear against the cylinder walls. They lasted about 500 miles each. In my opinion they are designed for lightweight applications. I originally used the pull style slave cylinder that was paired with the master. They also failed with fluid getting past the seals.
I ended up using a brake master cylinder from a 1956 Chevy Belaire. It's been working for close to 20 years without any problems. I paired it with the original style Chevy slave cylinder that mounts to the exterior of the bell housing. Again no failures with this unit. Like you master cylinder space was a premium and even more so for me as my peddle spacing is narrow as they were designed for a master cylinder that combined the brake and clutch into one reservoir. How dangerous is that (4 brakes and the clutch all combined together).
With the first failure, I and a friend, who builds race cars, double checked the geometry of my peddle and master cylinder and clutch slave and throw out arm. I was suspecting that a misalignment was causing the wear and fluid leaks. The alignments were perfect. We also checked that the master and slave cylinders were a match for each other.
Both of us concluded that it was poor quality and over rating of both the master and slave cylinders. They were both made by a well know and respected brand.
I will try to get some pictures of my installation which is a tighter than yours. I also used a hydro-boost system for my brakes which requires a power steering pump. When I show the truck people say "you put in power steering". I say no and most say "why would you put in a PS pump with no power steering". I simply say brakes. 90% don't get it.
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