OK here it is - '88 former 4+3, now ROD 6 spd. New CF DF clutch. Grabs so quickly (RIGHT at the floor), can barely shift gears, continuous grinding trying to get in reverse. Pedal travel is about 6.75", GM spec is 7 3/8" but the travel is limited by the master cylinder piston. Clutch fork travel - at the fork, measured against the bellhousing - is 3/8" (.40") and GM spec is 0.70". I have tried four different clutch fork push rod lengths from stock to stock plus 5/8" and I am only seeing a difference in the travel of <1/16"!!! So here's the unknown - before the new engine, I had a mechanic change the old clutch (he put in a LUK), and I remember him telling me he had trouble getting the clutch to release and that he had to modify "something." For one thing he changed the pushrod length to stock +1/4" and that seemed to work, except that it always felt like there wasn't much clutch travel between when it released and when it grabbed, like maybe 1/3 the total pedal travel length. When I put my new engine in, the clutch worked the same as before, but I fried it. Now I am having this trouble with the new CF DF. I have a new Master and new slave (though the fluid would always still get dirty) and I have bled the system 4 times and the last time I even used a Speed Bleeder - always the same result. WHAT THE *@#& IS GOING ON DAMMIT?!?!?!?!? I can't figure it out. The only thing I can think of is that somehow the clutch fork is incorrect (from when the mechanic did it) or that I put the throwout bearing in backwards - although I really doubt that. I absolutely DREAD pulling my brand new trans out AGAIN (3rd time). PLEASE ANY IDEAS?!?!?!?!?!

 

We found on my stock 87 when we installed a new clutch disk that the clutch rod on the clutch slave cylinder had to be the correct length or it would not disengage. The orginal rod had to be replaced with one that we had to make and it had to made longer. Hope this helps.

 

as i think about it, they said the same thing when they changed mine in my 88 (still 4+3)...they went thru three sets of clutches before they shaved the flywheel, or so they said...but it was a really low engagement point for the first month, then it came back up...sorry i don't have answeres, just letting you know someone else had similer problems

 

Thanks for the input guys, at least I'm not the only one. The flywheel has been turned at least twice. Maybe I will try one more time with a still longer push rod.

 

damn.

Do you have an adjustable pivot? That might help.

also, be damned sure the hydraulics are properly bled.

 

Not too familiar with the pushrods on that year, but some guys make their own using spherical rod ends on a threaded shaft.Just a thought. I'd find out exactly what that hack of a mechanic tweaked, replace it and start from there. I did a t-56 conversion a few years ago w/similar issues. It was a royal PITA but 100 percent worth it. Good luck

 

If you're only getting .4" of travel at the fork, then fix your hydraulic problem first. Changing the pushrod of course won't fix this, and if you do get length that works, it's only a MickeyMouse way around the problem. You could end up with a throwout bearing that is always partially engaging the pressure plate, or pushing the pressure plate in too far.

Are you sure your flywheel wasn't ground down too much? This will lower the clutch engagement point.

 

first try bleeding it again with the slave unbolted and hanging with the bleeder at the highest point.
they say it works best done that way.
I had to make a custom pivot ball (about .300" longer than stock) to get mine to work right, the aftermarket adjustable one wouldn't go out far enough for mine.
RJ

 

 

CENTRALCOASTER - As long as there is still some play in the slave cylinder range of travel and the plunger is not completely seated, a longer push-rod shouldn't put undue pressure on the diaphragm fingers. I was thinking that since a longer push-rod pushes the slave cylinder in deeper in the released state, then it would generate more range of travel when you depress the clutch pedal. Is this not right? Also, you mentioned "hydraulic problem" do you mean a bad slave, bad master, or more bleeding? I have two masters, and they both measure the same plunger range of motion. My slave is still quite new-ish, but I do notice that the fluid still gets dirty, so maybe a new slave is in order as the master is brand new right out of the box. I have bled it sooooooo many times - there just can't be more air. I'd appreciate more input from you. Thanks.

 

Mark, you can be a bonehead like me and take the tranny in mand out 7 times to adjust the pivot ball, the pushrod length and the TO bearing height.

Cause I'm too lazy to do the math.

I know Mcleod has some formulas somewhere (website or catalog) where you take measurements with a mic&calipers and you can basically dial it in in one shot.

Probably the easy way.

You think changing to the DF is bad, I went with a Street Twin and cursed, ranted, threw things, cursed some more....

 

Getting ready to install an ROD myself

 

It's a great trans, you will love it. Rock solid, perfect gear ratios, shifts a little tight at first. Personally, I thought the installation was really quite easy all things considered. This clutch problem has nothing to do with the trans.

 

The ROD should be here tomorrow or at the latest some time next week. I think ill go ahead and install the clutch, bell housing and hydraulics this weekend just to test everything before the ROD arrives

Glad to be rid of that old slush box

 

I bought a threaded adjustable clutch rod with lock nut at NAPA for my1985 DN/4+3 clutch,

I adjusted it until the relase worked and left it.

 

Can you install and adjust it with the trands still in the car?

 

Hey ID85 - do you know if the design is the same for your year as for an '88 (regarding the clutch push rod)?

 

Got mine here

Push Rod

 

Yes, I would just pull forward on the clutch fork and push the adjustable one into place.

If it starts to get tight, you may have to pull the salve off, insert the rod, then put the slave back on, worked pretty well actually.

It is a hollow rod with a bullet nose and a threaded rod that telescopes inside the hollwo rod.

I gave up on cutting up my long screwdrivers and grinding them down

 

On the fluid issue, there are 3 parts to the clutch hudraulics on the later cars and I think yours as well. Have you changed the clutch pipe/hose? I did all 3 parts and my fluid is crystal clear, I read somewhere the black coloration is from the hose falling apart. I'd pay good money to have a friggin' cable clutch release instead of the hydraulics they seem to be a PITA.