TR2/3/3A TR3 clutch issues

[Lukens]

Greeting Brothers,
I'm up in Ohio visiting family. I've got a clutch situation that I'm not sure how to handle. I've developed more free pedal travel than I used to have. With the pedal up, the master is fully extended and I can't push it's piston in (from under the bonnet). However, I can manually push the rod on the slave back into the cyclinder maybe 1/2". Depress the pedal and the rod comes out and disengages the clutch. Release the pedal and the rod returns (with the spring connected) to it's "home" position. However, from this position I can again with only "slight force", force the rod and piston back into the slave... no movement up at the master.
Am I compressing air? Do I need to bleed the line? Or am I pushing fluid around a leaking seal in the master?
I apologize for this vague description. Maybe through dialogue I can explain it more clearly. In the mean time I'll go buy some tubing and try bleeding it.

EDIT: Maybe a simpler explanation is to say that my slave cyclinder behaves as if the spring itself is not stong enough to fully retract the piston. ???
Russ

 

[TR3driver]

With the master piston fully out, the passage back to the reservoir is opened. So my guess is that you are pushing fluid through the MC and back into the reservoir when you compress the slave.

It shouldn't matter; on a TR3 there should be only a very small amount of motion available between having the slave piston fully bottomed in the slave cylinder, and pushing on the pressure plate. This is true even without any fluid in the system. Assuming it was correctly adjusted before, and you've inspected that the slave mount isn't falling apart; the most likely cause of suddenly having way too much free travel at the slave is a broken taper pin or throwout bearing. Unfortunately, correcting either of those (or other, less likely causes) involves removing the tunnel and gearbox. Probably not something you want to do at your relative's house (unless one of them is a fellow gearhead).

My suggestion is to disconnect the return spring at the slave, and see if that gives you enough clutch to drive home. You may need to pump the pedal a few times, but hopefully you can get the clutch to release that way.

Or, if you're not too far away, take it over to Ted S. in Pandora, OH. He can fix you up.
https://www.tsimportedautomotive.com/

 

[Geo Hahn]

...My suggestion is to disconnect the return spring at the slave, and see if that gives you enough clutch to drive home. You may need to pump the pedal a few times, but hopefully you can get the clutch to release that way...

FWIW - I suspect my fork pin is broken but I am able to drive if I leave that spring off. With the spring on I cannot disengage the clutch.

I have been driving it like this for 30 years, waiting for total failure, bad TOB, clutch to wear out or some other reason to pull the gearbox.

Not saying you shouldn't address the issue - just saying that if removing that spring seems to work it is quite possible it could continue to work that way for awhile.

 

[Lukens]

It shouldn't matter; on a TR3 there should be only a very small amount of motion available between having the slave piston fully bottomed in the slave cylinder, and pushing on the pressure plate.

You've lost me with that statement.

 

[CJD]

What he means is that the play at the pushrod shaft should only be .030". That is enough to know that there is play, but not enough to feel the piston move enough to notice. If you suddenly have a lot of play, I also beleive your throw-out fork pin has likely sheared.

 

[Lukens]

I am able to drive if I leave that spring off. With the spring on I cannot disengage the clutch.

George, do you mean the added resistance of the spring overcomes the hydraulic force of the slave?
With all due respect, that doesn't sound right. What am I not getting.?

 

[TR3driver]

It shouldn't matter; on a TR3 there should be only a very small amount of motion available between having the slave piston fully bottomed in the slave cylinder, and pushing on the pressure plate.

If you first push the slave piston as far forward (relative to the car) as you can, and then pull the pushrod to the rear as far as you can, there is supposed to only be about 0.1" clearance between the pushrod and the piston. That's the periodic adjustment described in the owner's manual "Practical Hints ..." (page 38 in the 6th edition).

When you push the piston forward, it hits a stop inside the slave cylinder. That's what I meant by "fully bottomed".

When you pull the pushrod and lever to the rear, they stop when the throwout bearing comes up against the fingers of the pressure plate. (If you were strong enough, you could continue to compress the pressure plate, but I don't think even Hulk Hogan is that strong.)

Clearer now? My point was that that clearance is set by mechanical stops and the adjustment (where the pushrod screws into the clevis). If it suddenly got much larger, then it is a mechanical problem, nothing to do with the hydraulics.

BTW, my return spring got stretched out as well when the taper pin broke. So I see that as a symptom, not a problem. If the return spring were not doing it's job (and everything else was normal), the worst you might notice is that the pedal is higher sometimes than others. Since it normally maximizes the freeplay, having it not work can not keep the clutch from working.

But when the taper pin is broken, there isn't enough range of adjustment to achieve the 0.1". So then the spring IS causing a problem, because there isn't enough travel to overcome the now ghastly large free play. That's why I suggested disconnecting the spring as a workaround. (I actually got in the habit of pumping the clutch up and then always holding the pedal partly down. Not a good habit to have, but it overcame the problem.)

 

[TR3driver]

I am able to drive if I leave that spring off. With the spring on I cannot disengage the clutch.

George, do you mean the added resistance of the spring overcomes the hydraulic force of the slave?
With all due respect, that doesn't sound right. What am I not getting.?

Geo is operating the same way I suggested to you : by leaving off the return spring, the piston remains extended and the piston, not the adjustment, takes up the freeplay.

 

[CJD]

It sounds like the "work around" of removing the spring will allow the release bearing to ride on the clutch fingers all the time. But, that's a moot point, since it all has to come apart in the end to fix the taper pin.

 

[Deleted member 8987]

It sounds like the "work around" of removing the spring will allow the release bearing to ride on the clutch fingers all the time. But, that's a moot point, since it all has to come apart in the end to fix the taper pin.

What you have here is what would later be called a self-adjusting clutch. Basically, fixed rod length, no slave return spring.
Counted on engine rev changes to flex the plate fingers to give you .0000001" clearance between fingers and bearing.
The spring makes no difference on sheared pins..and rod and spring connect at a place there is no joint between them to shear, rotate out of clock, any of that.
Removal of the spring gives you self adjusting is all....get you home....then fix it, put the spring back so you don't damage the T/O bearing or plate fingers.

 

[TR3driver]

It sounds like the "work around" of removing the spring will allow the release bearing to ride on the clutch fingers all the time. But, that's a moot point, since it all has to come apart in the end to fix the taper pin.

Yes, exactly. The later TRs were actually designed that way (for the bearing to run all the time), since as Dave pointed out, that makes the clutch self-adjusting.

 

[sp53]

Yes the self-adjusting is just a fuzz of a ride for TB on the forks of the borg & beck clutches and the spring and adjustment is supposed to keep the TB from not riding the forks. My experience has been the aftermarket return springs are too strong (perhaps because for and old system), but anyways try a spring with just enough mussel to keep the slave cylinder piston back and let the adjusting rod give the hair space and see how that works. I ran a system without a spring for at least 10 years because I did not know any better, and then when I hooked up a spring I got from one of the big 3 after I got a catalog, I could not get the clutch dis-engaged. This happened way before the forum, and when I took it all apart to rebuild the motor I replaced the clutch just for good measure and the pin was fine. Looking back I think my master cylinder or slave cylinders were weak and the strong spring held everything back. Now I run a spring, but it is one that I have configured over the years.

 

[karls59tr]

Yes the self-adjusting is just a fuzz of a ride for TB on the forks of the borg & beck clutches and the spring and adjustment is supposed to keep the TB from not riding the forks. My experience has been the aftermarket return springs are too strong (perhaps because for and old system), but anyways try a spring with just enough mussel to keep the slave cylinder piston back and let the adjusting rod give the hair space and see how that works. I ran a system without a spring for at least 10 years because I did not know any better, and then when I hooked up a spring I got from one of the big 3 after I got a catalog, I could not get the clutch dis-engaged. This happened way before the forum, and when I took it all apart to rebuild the motor I replaced the clutch just for good measure and the pin was fine. Looking back I think my master cylinder or slave cylinders were weak and the strong spring held everything back. Now I run a spring, but it is one that I have configured over the years.

I had this same issue a couple months ago with everything new and adjusted properly. The only way to get the clutch to work properly was to remove the return spring. Clutch works great without it. I'm curious to know if the the throw out bearing or forks were damaged on your car from running without the spring? I'm pretty sure I can hear the the throw out bearing rubbing( engine noise making it difficult to hear) when the clutch pedal is up.
I had the trans out twice earlier this year to try and resolve the problem and sure don't want to pull it out again until absolutely necessary....want to enjoy the Fall weather in the car:smile-new:
Seeing as how you drove for 10 years without the spring maybe It won't be so bad?
Forgot to mention that when I installed the new clutch setup I did install a new taper pin and backed it up with the extra bolt fix so that wasn't an issue.

 

[TR3driver]

My experience has been the aftermarket return springs are too strong

I've heard that theory before; always seems hard to believe to me. The return spring is supposed to be very strong, a common hardware store spring isn't nearly strong enough to reliably return the piston to the bottom. And even the strongest spring takes a lot less than 100 lbf to stretch (after all, you have to stretch it into place by hand); while it takes several hundred lbf to operate the clutch.

And the only way for the hydraulics to be "weak" is for them to leak or break. Both tend to be pretty obvious.

 

[sp53]

Ok here hear is my experience again. I bought the spring at Tacoma Screw and the spring is kinda wippy and the spring pulls the slave cylinder piston back enough to stop the drag of the natural gravity of the kinda homemade spring-less/ self-adjusting spring system. It is not good to have the TB rubbing and perhaps the clutch forks wore out more by not having a spring, but I did not notice the clutch being trashed. Take my advice or not, but I suggest to play around with the spring and see. The reverse is true also, on my 66 Ford pickup the return spring was weak and let the TB rub on the forks and that engaged the clutch and kept wearing out clutch disks so bad they would start to slip in a year and I could not even hear it rub and I think that is want Randall is alluding to. I still have that truck (bought in 1975) and after I got a stronger spring it fixed the problem. For me the tr3 experience is different, perhaps from the gravity of the hydraulic system or the drag of the slave cylinder, I do not know for sure, but the clutch set up in it now has been in there since 1993 and I am thinking about driving it today.