Clutch issue

[seddons]

I have my Chevy 350 installed backed with a SM465 with the GM factory bell housing and slave cylinder (with the .81 bore). I have a Wilwood ¾” clutch master cylinder attached with a #4 braided line. Here is the problem, I have full disengagement of the clutch but, it takes all I have to hold the clutch petal down. I’m not a wimp so this is unnaturally tuff to work. Everything is new, no remanned or used parts including the clutch assembly. Anyone have any suggestions?

[Flingarrows]

Any pics?

I used a set from an a 1990's k2500 with a 68-72 clutch fork, and my pedal is like butter. Nice and smooth

[Flingarrows]

Another dumb question: any binding on the throwout bearing? You didnt mention if it was hard to press, only hard to hold

[seddons]

When I installed the transmission the first time I had the bell housing attached to the engine and when the petal was so hard to depress I thought it was the throw out bearing binding so I removed the transmission and installed the bell housing on the trans. The clutch fork and bearing slide easily with no interference at all. I reinstalled and it is the same thing.

[jeeper]

I'm no expert on this so take what I say with a grain of salt.

I think the problem is the mismatch between the master cylinder and the slave. The bore needs to be the same size on both units.

The hydraulic fluid is not actually supposed to give any mechanical advantage. It is merely a convenient linkage.

[seddons]

Thanks, they actually are pretty much a match, the MC is .75 and the slave is .81. In fact the GM MC is .71 so the difference I am told falls within an acceptable difference. I am wondering if my #4 hose is the culprit, would #3 work better?

[jeeper]

I read this page when I was setting mine up.

At the bottom of the page is a troubleshooting guide. It says you have an improper linkage set-up or the wrong pressure plate spring load for your linkage.

[Flingarrows]

Are you using a stock clutch fork?