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TR6 Clutch will not disengage

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airlifter

Jedi Hopeful
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As I posted earlier I was having trouble with the clutch sticking. Well, I replaced the front cover and installed the upgraded bronze sleeve. I also replaced the clutch fork pins. I made sure the clutch was aligned properly.

I now have everything back together and the clutch will not disengage. I bled the slave cylinder. I still have the transmission tunnel off and I can see the lever moving. I tried taking a pipe and operating the arm to see if the slave cylinder was maybe not pushing the arm far enough. No joy.

Any ideas.

Thanks, Pete
 
I just finished pulling the transmission to make sure that I did not install the clutch plate backward. It dropped down before I could grab so I still don't know. I know that is right now but I am going to wait and see if anyone has any other suggestions before I start putting it back together.

thanks again.
 
Did you install the ground shank "dowel bolts" that locate the bellhousing to the rear plate? Are the pins that locate the rear plate to the engine block in place?

I don't understand your comment about the clutch plate "dropped down". I assume you mean the friction plate, which should be firmly locked in place by the pressure plate, certainly long enough to look through the center and see which way the friction plate is installed.

Only other possibility I can think of might be a failure of the clutch cover somehow. I might try to find a way to operate it off the engine, to make certain the pressure plate moves as it should when you compress the arms. Maybe set it up in the press, with the friction plate underneath and use the press ram to operate the arms.
 
Yes, the friction plate is what I meant. I did not remove the transmission completely and I did not have a lot of room to see. I loosened the clutch mounting bolts to remove the friction plate.

the dowels are in place.

i don't have a press, but that sounds like a good idea.
 
airlifter, I have had this trouble before, or one like it. and it turned out to be the master was not throwing the slave far enough and needed a new or a good rebuild. We are only taking a 1/4 inch on the rod difference. Now you may need the adjustable rod, it has solved this problem for a few members.

Wayne
 
I had this problem too (more than once). The end of the lever moved by the slave push rod, only moves about 1/2" (full travel). Any air in the slave can prevent "full" movement, and the clutch won't disengage. Once, I failed to install both bolts of that thick plate that holds the slave to the tranny/engine, and it was able to bend enough to not disengage the clutch. Also the clevis at the brake pedal, that presses the rod into the master, can become oblong and not allow "full" motion. I have seen incorrect throw-out bearings causing issues, as well as incorrect pressure plates -and I over stressed a pressure plate by increasing the length of the master push rod.

I usually bleed mine by removing the slave, point it down so the air can float up to the bleed nipple, push the piston as far into the slave as possible and clamp it there, then bleed until no air bubbles come out the clear hose attached to the bleed nipple. It doesn't take much to keep it from working.
 
The clutch, pressure plate and throw out bearing only have about 500 miles. It was disengaging fine before I replaced the front cover and sleeve.

I did use a pipe and operated the arm and could not disengage the clutch.

I am curious about how the clutch acted when you over stressed the pressure plate. I moved the Clovis on the master rod t raise the pedal. Would this cause the same problem?

I thought I got all of the air out of the system but I wii double check.

i probably won't get to work on the car for a few days because of other commitments. Might be good to get away from it for a couple days.

Sorry for the green horn questions, Pete
 
I'm not sure when I did the damage, but the clutch got harder and harder to press in. I had lengthened the push rod to the master, and also added the adjustable push rod on the slave (longer). I had a cross shaft with a broken taper pin, that had been drilled, tapped and through bolted -but with a non-grade-8 bolt, that broke inside the shaft, and I re-drilled over-sized, and probably not exactly in the correct orientation. The clutch disengaged, but started getting really difficult to push the pedal -it seemed to be much more difficult as the engine got warmer. My knee would get stiff with a short ride. It was a mess. When I took it apart, the throw-out was dragging on the pressure plate fingers, and had worn an obvious groove in them. I think the springs were sprung. It had got to the point where I didn't enjoy driving it.

When I put it back together, I replaced everything by getting a TRF clutch magic kit. Some of those parts probably didn't need replaced, but I did not want to take it apart again. Ever. Now the clutch is so easy and smooth that I wish I'd have done it long ago.

We live and learn. Sometimes by others questions. If you hadn't asked, I'd not have admitted to these 'green' mistakes. I don't think you could over stress the pressure plate springs by moving the pin. -But using a pipe wrench might do it, but I doubt that's enough leverage. Also make sure you have the dowels in the flywheel that align the pressure plate. Often the most difficult problems have the simplest solutions.
 
TR3 driver,I was wrong....there was no dowel bolts when I removed the transmission. I know the dowels are in place where the rear plate mounts to the engine. I cannot find reference to them in the Moss catalog or TRF online catalog.

Texas, i double check the dowels on the flywheel.

i have the old pressure plate. It was working fine. I just decided to replace it when I had the engine out,
 
airlifter said:
I cannot find reference to them in the Moss catalog or TRF online catalog.
Click to expand...
Item CL84 here https://trf.zeni.net/TR6bluebook/index.php?page=83
Moss apparently supplies plain dowels, item 30 here https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=32713#top
As does Gunst https://www.buckeyetriumphs.org/technical/clutch/ReliableClutch/ReliableClutch.htm

The plain dowels will probably work fine, but my feeling is that the factory must have had some reason for switching to the special dowel bolts; so I made my own by threading some drill rod on both ends.
 
I'll start by apologizing for not having read every word of the previous responses. I just quickly scanned (old age short attention span) for any reference to the flexible hose. Now I'll assume that sixes came stock with a hard polyethylene (semi-flexible) line, which in theory should be good 'forever' (until it gets kinked). Or might someone have switched for a later 'better' after market stainless outer with en elastomer rather than polymer) inner line. If so, our old rule 5&10 shop rule was 'if its 5 yrs old, test it, if its 10, throw it out. It just might need a stent, like I probably do.
 
Here is where I am now. I removed the flywheel just to make sure the dowels were in place on the rear engine plate. There were no positioning dowels in the flywheel for the clutch. I did install the dowels before replacing the fly wheel.
The locating was in place for mounting the flywheel.

As I said before, the clutch etc only have about 500 miles

Is there anything else I should check before I reinstall the transmission?

i really don't want to pull the transmission again.

thanks again
 
Replaced the transmission and checked the throw on the operating arm It is 1/2 inch. The clutch will not disengage. I am considering putting the old clutch back in. It was working fine. I just changed it since I had the engine out anyway.
 
I moved the pin for the master cyl rod to the2nd hole now the arm moves about 3/4 inch. Still no joy.

This hobby can be sooooo relaxing!!!
 
I have the transmission out again. What I know is that the engine plate dowels are in place. The flywheel locating pin is there. The clutch pin is OK. I replaced the master and slave cylinders a couple ears ago but I understand these could still be a problem.

I found that a PO had installed an "adjustable" master cyl. Rod. This may have caused over travel of the clutch fork and caused the damage that Texasknuckehead mentioned.

I have dowels for bellhousing mount and am ordering the proper master push rod. Once I have all this installed I hope all works properly. I think I will also order a new pressure plate to eliminate as many potential trouble spots as possible. Your thoughts?
 
I feel for you and have been there.

Just to recap...
There should be 2 dowel pins that locate the bell housing (tranny) to the engine -the holes in the tranny are larger for these.
There should be 3 dowel pins to align the pressure plate to the flywheel, and grade 8 bolts with lock washers to attach the pp to flywheel.
There should be a bushing in the center of the crankshaft that your clutch alignment tool fits snugly into so the transmission main shaft will also fit snugly centered.
If you have a broken taper pin in the cross-shaft, now would be a great time to identify it,
even if you don't have a broken pin, most would install a grade 8 through bolt, either replacing that pin or as additional insurance. Be sure it is installed properly and wired to not be able to spin out.
The 2 pins that protrude into the sleeve that holds/moves the throw out bearing should not have excessive wear.
The 2 bushings pressed into either side of the tranny housing for the cross shaft should not have much wear.
The clevis attached to the clutch foot lever that presses the master push rod, should not be very oval or have much wear.

If all these things are true, your hydraulics function normally, and you have no air in your system, your clutch should work fine.
The normal amount of travel at the end of the slave push rod (with the pin in any of the 3 holes) is 1/2". The pin is normally in the center hole.

-with a lengthened master cylinder push rod, lengthened slave push rod, and a miss-oriented cross shaft to throw-out mechanism, my clutch still disengaged. It was difficult, but it worked. I can't guess why movement of 3/4" is not working for you -something doesn't add up. You say 'about 3/4"', measure it and be sure. I know mine moves exactly 1/2" because I secured a ruler to the underside, butted against the engine, and took pictures of the slave end from the same vantage point with the pedal up and down. 1/4" difference of movement there is a lot.

Good luck, let us know what you find.
 
TexasKnucklehead said:
I feel for you and have been there.

Just to recap...
There should be 2 dowel pins that locate the bell housing (tranny) to the engine -the holes in the tranny are larger for these.
There should be 3 dowel pins to align the pressure plate to the flywheel, and grade 8 bolts with lock washers to attach the pp to flywheel.
There should be a bushing in the center of the crankshaft that your clutch alignment tool fits snugly into so the transmission main shaft will also fit snugly centered.
If you have a broken taper pin in the cross-shaft, now would be a great time to identify it,
even if you don't have a broken pin, most would install a grade 8 through bolt, either replacing that pin or as additional insurance. Be sure it is installed properly and wired to not be able to spin out.
The 2 pins that protrude into the sleeve that holds/moves the throw out bearing should not have excessive wear.
The 2 bushings pressed into either side of the tranny housing for the cross shaft should not have much wear.
The clevis attached to the clutch foot lever that presses the master push rod, should not be very oval or have much wear.

If all these things are true, your hydraulics function normally, and you have no air in your system, your clutch should work fine.
The normal amount of travel at the end of the slave push rod (with the pin in any of the 3 holes) is 1/2". The pin is normally in the center hole.

-with a lengthened master cylinder push rod, lengthened slave push rod, and a miss-oriented cross shaft to throw-out mechanism, my clutch still disengaged. It was difficult, but it worked. I can't guess why movement of 3/4" is not working for you -something doesn't add up. You say 'about 3/4"', measure it and be sure. I know mine moves exactly 1/2" because I secured a ruler to the underside, butted against the engine, and took pictures of the slave end from the same vantage point with the pedal up and down. 1/4" difference of movement there is a lot.

Good luck, let us know what you find.
Click to expand...

All of these were OK except the dowels in the transmission housing and the master rod.
I checked the movement at the operating arm with a dial indicator.
since I have the transmission out anyway I think I will remove the flywheel and take the whole thing to a local shop and check it on a press.
 
I rigged up a screw press to check the clutch assy. Using a .008 feeler gage between the friction and the pressure plate disc I could move the feeler gage with resistance when the fingers were depressed 3/16 inch. The gage would move freely with the fingers depressed 1/4 inch.

This sound about right?
 
I had a similar problem I will bet it is still the throw-out bearing I went thru 3 new ones until it solved the issue I will not name the supplier. If that isn't the answer replace it with an automatic tranny
 
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