TR2/3/3A Clutch adjustment with mixed TR parts?

[karls59tr]

I installed a new TR3A clutch and adjusted the slave as per the manual. The clutch works all right but I can hear a disconcerting metal rubbing when the clutch pedal is up. I'm assuming that the the clutch pressure plate"arms" are rubbing against the TOB. The gearbox is from a TR6. I've tried both locations for the slave cylinder...the TR6 mounting and the TR3 mounting but the problem persists.

The PO had installed a TR4 Clutch MC on the car and I had no issues driving the car with that set up for many years before I changed out the clutch but...
(A) I'm wondering if this setup is an issue in the clutch functioning? ...

(B)Is there a method to adjust the MC pushrod to the correct position "before" adjusting the slave?....

(C) Differences in MC TR3 and TR4 "bore sizes" causing problems?Wondering if I should switch back to a TR3 MC?

(D)Would installing a TR6 clutch have been a better option???

(E)Anyone out there have a TR6 box in a 3 and which clutch slave mounting was optimal.

 

[Marvin Gruber]

Are you using the adjustable rod on slave cylinder or the solid rod. Sounds like it is to tight and keeping TOB pushed against CP. You might need the spring to keep trans arm pulled back.

Marv

 

[karls59tr]

I'm using the adjustable TR3 rod with the spring. I get a little dyslexic at the adjustment:topsy_turvy:....to get the TOB to not touch the CP do I turn the adjustment rod towards the front of the car or towards the back of the car?

 

[TR3driver]

Try disconnecting the slave pushrod entirely, then push the lever forward and start the engine. If you still hear the noise, it can't be the TOB.

AFAIK, TR3 Girling and TR4 clutch masters should have the same bore (.75"). Later TR6 went to a smaller bore on the clutch MC, which sometimes causes problems with lack of travel (clutch still drags with pedal to the floor). But either way, there should be no pressure with the pedal released, which means the MC has nothing to do with TOB position when your foot is off the pedal.

For the same reason, the MC pushrod adjustment has nothing to do with the slave adjustment. In both cases (for TR3/4), the piston should return fully home in the cylinder. For TR4A-TR6, the slave piston remains extended (to remove all free play at the slave), but the MC piston should still return fully and the pushrod have some free play. Later TR3A eliminated the MC pedal stop entirely, but on earlier cars it must be adjusted to leave some freeplay in the pushrod (or there is a factory note suggesting to remove the stop bolt entirely). The book says .030", but I set mine a bit tighter (roughly .015") and it hasn't seemed to cause any problems for me.

I ran with a TR3 clutch in front of my TR6 gearbox for several years. I don't know that it is "optimal", but I used the TR3A slave and slave mounting with no problems. Only issues were that I had to make up a shorter pushrod (to account for the increased flange thickness of the TR6 gearbox), and a small tab to stretch the spring back to it's original installed length. (Without the tab, the slave piston would not always return fully, which made the clutch pedal higher on next activation. Not really a problem, just irritating.)

I'm still using the same mounting, but I went to a TR4A clutch when I installed the alloy flywheel (since the one I got was only drilled for the later clutch). As clutches go, I liked the larger TR3 clutch better. Operation was just a bit smoother and the 4A clutch has a tendency to chatter a bit when cold (which could be caused by the alloy flywheel rather than the clutch). But it's not a big difference, and I didn't bother to switch back even when I moved that setup from the wrecked 3A to the current TR3.

But with either mounting, the important bit is that you have the necessary freeplay at the slave. Different books give different numbers but I believe 0.1" is correct for the Girling slave. 0.075" is specified for the earlier Lockheed slave (and seems to work OK for me even with the Girling slave). Using the smaller number leaves less allowance for wear, though (the gap closes up as the friction plate wears), so it's probably wise to check it more often.

 

[Marvin Gruber]

Shorten the rod a little at the time. Back the locking nut off about two turns, screw rod in until locking nut hits turnbuckle and try. You may have to do again

Marv

 

[JerryVV]

Check the half moon cover plate and look for any evidence of the PP bolt heads scraping the plate.

 

[Geo Hahn]

Check the half moon cover plate...

Ding ding! I like that idea.

 

[karls59tr]

Not sure what you mean? Do you mean the PP bolts scraping the pressure plate or the clutch disc? The PP bolts go into the flywheel. What am I missing?

 

[CJD]

The cover could be installed wrong or it could be dented. That would allow the cover to rub on the spinning flywheel. They are talking about the steel cover that goes on the front, bottom of the tranny bell housing and meets the back of the engine.

 

[TR3driver]

The part I don't understand is why the flywheel would move forward (or the plate to the rear) when the clutch is released. Seems like it would be the other way around. But apparently it's pretty common to wind up with bolts that go all the way through and stick out on the other side. My current TR3 had a lot of wrong bolts (both too long and too short) when it came to me, not to mention a few places where someone had tried to force a metric bolt into SAE threads.

 

[JerryVV]

I mistakenly mentioned PP bolts but I believe they were the ring gear bolts that were scraping on my cover plate making a similar noise to what you described.
JVV