Clutch Cylinder

[Mike Bartlett]

I have gone through one remote clutch master cylinder and now it looks like I have another one bad. I tried bleeding it today and like my old one I found aluminum particles in the fluid. My clutch pedal gets harder and harder to push esspecially when it gets warm. I checked the slave cylinder and it seems fine. The particles in the fluid are definately from the master. The geometery/linkage seems fine on both the pedal to master cylinder and slave cylinder to clutch fork. I did recently notice my clutch fork rubbing my frame so I filed that so it no longer rubs. Could this have taken out my qty-2 master cylinders?? If so how could that be? You can jam on your brake pedal and not hurt a thing.

I have a rebuild kit on its way but I am in fear I will only get another 1000 or less miles out of this one. The last mater cylinder I put in was brand new. I figured this time I will just rebild it.

Any ideas??

Thanks....

Mike

[saltytri]

What make and model?? I also had one suffer premature death (about 1500 miles) and don't know why. Same symptom: lots of aluminum powder in the fluid. But it was never harder to push. It just got mushy and lost all function within a couple of miles. Of course, it's fun to drive home without a clutch. What stop sign? Was that light really red?

Mine was a .700 Wilwood like this:

http://www.wilwood.com/Products/006-...RRMC/index.asp

Of course, my friend David K. rushed me a new one right away and all is fine now but I've got only a few hundred miles on it so far.

Anyone have any ideas why this happened?

David

[Tommy]

When the aluminum clutch master cylinder in my car began to leak, I discovered the shaft from the pedal to the cylinder was not perpendicular to the cylinder. It had caused the cylinder to wear unevenly until it began to leak. After studying the geometry of the pedal, I realized there was no easy way to fix the alignment. So, I decided to go with a steel master cylinder rather than an aluminum one. Here's a link to the CNC Master Cylinder I'm now using.

[saltytri]

Tommy:

Would you try to post that link again? It didn't make it.

David

[Fake Snake]

I had an AFCO die in 2300 miles. I just started to bypass the piston slowly. (I was hoping it was not the McLeod hydraulic throw out going south since I had just put a new engine in! ) I did not see any part any particulate matter to speak of, at first. I had drained the master cylinder out completely into a container and after everything settle out, there was some extemely fine black particulates in the bottom. I opted for replacement. Now that you have mentioned the need for perpendicularity, I guess I had better check it out. I only have a few hundred miles on the new unit.

[Tommy]

Here's the link to the CNC MC.
http://www.pitstopusa.com/searchresu...ategoryID=3616

[Mike Bartlett]

Mine is the AFCO "torpedo" with the remote reservoir. Maybe the steel one is the way to go? Sure can't figure out why 2 masters have gone bad and both have the aluminum particles in the fluid.

Mike

[Tommy]

For those of you who may be curious, I'll expand on my comments about the geometry of the clutch shaft affecting the life of an aluminum master cylinder. The clutch pedal moves the shaft that presses against the piston within the master cylinder. If the shaft pressed precisely perpendicular to the piston (parallel to the walls of the master cylinder) there should be relatively little wear on each stroke, and the wear would be even around the entire piston. In actual practice, the end of the shaft connected to the pedal swings in an arc, resulting in something other than precisely perpendicular movement. Ideally, the shaft should be perpendicualr to the piston near the center of its travel on each stroke. On my car, the shaft was connected to the pedal at a point well below the centerline of the master cylinder. Consequently, on each application of the clutch, the shaft was pushing both in and up on the piston. I believe this tended to cock the piston in the cylinder, causing rapid wear on the top and bottom of the cylinder. This was confirmed by measurements of the leaking cylinder bore. ... I tried to align the clutch shaft by moving its attachment point higher on the clutch pedal. But this reduced the effective throw of the shaft and would not allow the clutch to fully disengage. So, I abandoned the softer aluminum master cylinder in favor of the CNC steel one.