I've having some issues with my clutch that I cannot seem to figure out. It's a long story... A few years ago my dad sold his 79 f250 that he bought new. I bought the truck back from the guy that owned it after he took the engine out, lost some pieces, and gave up with it.

In August I finally got the truck back together and running. I rebuild the engine, machined the flywheel, and put a new Centerforce II clutch, pressure plate, and throwout bearing on it. I also put a new clutch fork on it because it was one of the "lost" parts. I happened to have the very original fork (which had been replaced years ago because the adjusting rod pocket had a hole worn in it). The fork i put in looked just like the original. The aluminum pivot block looked good.

After reassembling everything I found that the clutch behaved very strangely. As you stepped on the clutch there was the normal freeplay, then consistant and reasonable pressure until about half-way. You could tell that was where the clutch diaphram released and then the pedal was extremely soft for the remainder of the travel to the floor. THe problem lies with letting the pedal up. There is very little pressure so you have you have a light foot to let up the pedal. Now when you get to the stiff part, it gets so stiff, so fast, that you can't control it and you basically pop the clutch. This is very frustrating behavior.

The first thing I did was to rebuild all the linkage. I took the pedal assembly out from under the dash, replaced the bushings, regreased, and reassembled. I replaced the plastic bushings on the clutch rod from the pedal to the equalizer bar also. I also replaced the bushings and felt washers on the equalizer bar. These changes made no difference. At this point I thought that maybe I had a bad pressure plate. When my dad sold the truck, he had a Centerforce I in it that was perfectly smooth with a progressive pedal feel - it felt like every other clutch i've ever driven.

I have checked and double checked all part numbers.

I pulled the transmission and replaced the clutch with a new Centerforce I. I reassembled everything, and it felt exactly the same. At this point, I bought a new equalizer bar because mine had a little bit of play in the block that pushed on the adjustment rod. No difference.

At this point, I'm out of ideas, but I know for sure that I'm not happy with the clutch. The problem is that I'm not sure where the problem lies. I don't want to put a third clutch in it and find that it still doesn't fix the problem.

Any ideas?

 

Do you have a return spring similar to one of these?
The pic is kind of cockahied but then so am I.

 

Yes, I have both the return spring that attaches to the fork and the big spring under the dash.

 

Did you have anyone work the peddle while you crawled around under the truck to watch the engagement and disengagement of the clutch?

 

I don't know if this is of any help and I am just kind of tossing it out there. My memory is a little fuzzy because it was years ago and half a continent away a friend with a Chevy had clutch problems related to the throwout bearing. It turned out there was a short and a long bearing and he had the wrong one, resulting in some odd pedal behavior.

 

I called Centerforce today and tried to get some ideas from them. They suggested a few items to check out. One item of interest that he mentioned was that some time ago, they switched from using Luk clutches to "Heavy Duty Valeo" clutches. That explains why Valeo is stamped on the pressure plates and why there is a slightly different hat design between my new Centerforce pressure plates and the old one. I had the truck up on a lift today and we changed out the throwout bearing, put another new fork in it, and changed the pivot pedastal.

All in all, it is exactly the same. I had someone help me work the clutch and watch the linkage and everything looks fine. There is no flexing in the linkage, no slop... Everything looks perfect.

The only think we can come up with is that what I am experiencing is just how the Valeo clutch is going to be. I'm just about to throw out the second centerforce and just get a remanufactured Ford.