Clutch Adjustment

[daren_p]

I put in a new Center Force Dual Friction clutch and need to make some adjustments because it engaged/disengaged about .5" off the floor. So I lengthened the rod and it now engages about 1/3rd of the way up, which seems about how it was with the factory clutch. Now I didn't adjust the top switch but according to the manual the pedal should be about 7" off the floor & mine measures just under 6" (that was just a rough measurement taken with the carpet in place so I'm sure you could easily add .5" to that) but I'm pretty sure that was the height set at the factory as the car was completely origional when I got it and had 19k on it. It also is inline with the brake pedal or maybe slightly above. So should I leave it set where it is or move the stop so the pedal comes up more?

My other question is in regards to the TOB. I took a look through the clutch fork inspection cover in the trans and see that the TOB rests on the pressure plate fingers even when the clutch isn't pressed. Is this normal for for a hydraulic clutch system? I don't think there is enough pressure to be moving the fingers at all, but I wasn't sure if the TOB was supposed to be spinning all the time.

 

[ericbev]

When I did my clutch I didnt measure the distances like the manual suggests. I made sure the engagement point was in the middle of the pedal travel distance allowing for complete engagement/disengagement and I also made sure the pedal had the adequate freeplay at the top to allow the relief valve to do its job.

As far as the TOB, mine is the same way. With the slave rod just sitting against the clutch fork it is ever so slightly pressing the TOB against the PP fingers.

In my friends EVO8 that I just changed the tranny on, the TOB is attached to the damn pressureplate via this extremely stupid clip. This would lead me to believe that this is a normal condition, but hey what do I know.

 

[daren_p]

I now have it adjusted somewhere between 1/3 & 1/2 way up, seems to be about where the stock pedal is. As for the TOB I was just curious about it resting on the pressure plate fingers all the time as you would think that would cause them to wear out quickly but from what I can figure with our hydraulic system the slave is always going to want to push out, therefore always resting on the fingers no matter how you adjust it, unless I missed something?

With the old american mechanical systems the TOB doesn't sit on the PP fingers (or atleast thats what my old man said) unless your shifting.

 

[ericbev]

Correct. In a hydraulic system the rod is always going to be putting pressure on the clutch fork, which is esentially just sitting there, moving the TOB towards the PP fingers.

Yeah our 65 corvette is the way your oldman is talking about. The TOB does not touch the PP fingers until the pedal is pressed.

I went and dug through my manuals and archives and couldnt find out definitivley if this is normal or not. I cant believe nobody else has piped in here yet.

Did you check for wear on the arm and pivotball and/or replace these as well?

 

[GVR4592]

Extending the rod is a hack for covering up an existing problem.

http://www.roadraceengineering.com/clutchandflywheeltech.htm

 

[ericbev]

Where did we mention extended slave rods? Darren and I know just a little better than that.

However, you could help us by peeking in the clutch fork boot and see if your TOB also rides on the PP fingers like ours does.

 

[GVR4592]

I misunderstood what he was saying, he said he lengthend the rod. I thought he was talking about the slave rod. My mistake.

I'd check my TOB, but car is taken apart at the moment.
Sorry.

 

[ericbev]

I knew you misread it. I just figured I would hassle you a little.

 

[daren_p]

Yes, while I was doing the clutch I replaced both the pivot ball and fork. The car only has 43K on it but I like to do it right the first time GVR4592 I know it was just a miss read on your part, but good to pass on the info when you think someone is doing something wrong. Personally I would never use a "bandaid" fix . So the TOB resting on the PP fingers must be normal but I can't believe out of all the wisemen on here, no one can confirm or has checked this?

 

[pneumo]

The tob is supposed to rest on the pp, it's normal. It's a bearing, so it's OK for it to spin constantly. There's almost no pressure on it until you step on the clutch.