Hydraulic clutch set up- non Mopar but Mopar related..

[Mike67]

Need some help guys..this isn't a Mopar but it's preventing me from working on my Mopar and tying up our lift....hoping someone can shed some light on a GM t56 hydraulics.
So a while back we finished my fater in-laws 67Nova LS/ 6 spd swap. It ran & drove great with the only problem being what we thought was a pilot bushing/bearing...changed it out for an oiled bronze unit... Any way initially you would drive about 15 miles and it would start squealing...really loud! Car could cool off for 15 minutes and no problems for another 15 miles...the only way it stopped is if there was a load on the trans...like accelerating..
Now this is where things changed and I'm not sure how...I have always been there to pull or install the trans except this last time and for reasons I cannot explain after it was installed they could not get the clutch to disengage.. It appeared to me after we pulled it again that there was a problem with the pressure plate only some of the fingers would actuate...I thought they might have dropped it but swear they did not..
I ordered a new clutch and pressure plate ( Spec 1) new TO, shimmed to spec .190" clearence recommended was .175-.225, bled the slave until I'm blue in the face but we still have the same problem...clutch will not disengage.
When we built the car I ordered and OE replacement clutch set up and McLeod mc conversion kit....When I connected the line I stuck the vacuum on it for maybe 5 seconds and pedal was instantaneous.... No other adjustments were needed...I've run several quarts through this one & I'm at my witts end.. I've videoed the slave moving the TO and the fingers being compressed...looks to be traveling about .375- .500".... I read somewhere that a stock set up moves about.400".... Any advice???
Thanks guys!

 

[woody3037]

Chevy junk.

 

[Steve Garner]

Couple of thoughts. Are you sure the disc wasn't put in backwards? If so the torsion springs on the disc could be bound up against the flywheel bolts. The other thing to check is the input shaft intrusion into the pilot bushing. Specifically, does the pilot end of the shaft turn freely in the bushing? Secondly, take a measurement from the face of the trans to the beginning of the bearing surface on the input shaft. Then take the measurement from the face of the bellhousing to the face of the pilot bearing. You are looking to make sure that the the part of the shaft that flares up towards the spline is not binding up against the face of the bushing (shaft too long, bushing sticking out too far or too long).

Sounds like you have enough travel, assuming it's a belville spring type clutch. If it's a three finger type pressure plate you want to be sure the face of the 3 fingers are all parallel (equidistant from the face of the flywheel).

 

[Mike67]

Ya the clutch and the type of flywheel will only go one way...
I was working through everything in my head earlier and pretty much came to the same conclusion that the tolerance on the pilot is so tight that it's actually turning the input shaft...physically that's the only logical thing. I dont know why I didnt think about it before...I wasn't there when they installed the pilot, but he did say he test fitted it on the shaft and seemed ok.
I marked the fingers to see how the TO is riding just in case we pull it (when we pull) again....lol!
I don't know to take some crocus to the input or try to hone the pilot ...or buy another bushing...and try to find a little more clearance...I couldn't find what the spec was for the bushing and input shaft clearance. The p.p. called for .175-.225, I set it at .190
Thanks for the advice, been feeling like a lepper with this post...lol, thanks again!

 

[coloradodave]

Chevy junk.

Thanks for helping....

 

[furyus]

Could the input shaft be too long, and binding when you tighten the trans? I would back the trans bolts out, and if this is the problem, you can put washers between the trans,.and engine until it works correctly. Then you know how much to shorten the input shaft.

 

[Mike67]

It shifted great before, but I am going to measure from the BH to back of the crank and compare to length of the input shaft.
Thanks!

 

[RT K_line]

If you still have the set clearance at the disk then I would say you are right to look at the input shaft pilot bushing. Does it stay engaged enough to shut down the engine? Or just make noise? Did the engine and trans come from the same doner vehicle? When you pull it out again I would look to see if either side of the bushing has any type of witness marks that might indicate a need for offset dowels to center it. Just a few thoughts.

 

[Mike67]

Thanks Ken,
The trans is out of a 2000 SS, motor is actually an L59( iron truck block). It came with the 243 heads so I swaped an LSII intake, the 5.3 didn't come with a manual trans but the 4.8 and 6.0 flywheel does, so it got a 6.0 flywheel, PP, clutch, TO & slave.
From the initial install the only problem was the squealing after several miles. Shifted easily clutch disengaged at half pedal... We put an oiled bronze bushing in place of the roller after reading some recommendations.. It was a tight fit and we had it turned .0010, which seemed right when compared to the roller but the same problem persisted, personally I think the Bush in was turned too much and it was spinning in the crank. Pull trans 2nd time, placed roller same issue maybe even worse I think ....pulled 3rd time, found right bronze perfect tight fit....I wasn't there on the install but looking at the wear pattern they thought the others were driven in too far so the left it out about .125 closer to the trans...
Thats when they started the motor and pushing the clutch it grinds the gears.... I racked my brain and thought it was air in the slave, not..thought it had to be the PP , had some odd chatter marks on one of the lift spring that connect to the fingers...
Ordered a new PP, clutch set everything up and no bueno, pulled again noticed a slight ridge on IPS...Like I said earlier I don't know why I didn't suspect the bushing again..but thats the only mechanical explanation I can think of now...
What bugs me about the whole therory is that you shift gears when the input shaft is spinning while driving so why is it grinding when going from neutral to 1st or any other gear???

 

[RT K_line]

I googled that swap and it came up with info on an added bracket needed at the master cylinder push rod to pedal connection. I don know if it's your issue but look it up .https://www.cartechbooks.com/techtips/ls-swaps-transmission-and-clutch-guide/
Edit; It's at the bottom part of the article

 

[Mike67]

Ya the Mcleod conversion had all of that