TR2/3/3A Squeaking Clutch when hot

[Ariddick]

Need some troubleshooting here. Having a hard time fixing/locating this loud sqeak.
I rebuilt a TR4 gearbox and replaced my stock TR3 gearbox.
Runs great, but about 2 weeks later, I consistently get a loud squeak about 10 minutes into a drive.
Since it is consistently after 10+ minutes, I assume it is due to heat.
While idling and in neutral, the noise is present at higher RPMs (1200+) or when I am pressing on the clutch.
Noise gets louder when pressing on clutch.
I assumed throw out bearing and replaced with new bearing, but noise is still there
Third pull of the trans and I have now replaced the throw out bearing carrier, pilot bushing, and swapped out the fork.
I rotated the pins on the fork also so there is little play.
I also flipped how I mounted the bell housing dust cover as I’ve read those sometimes rub on the flywheel.
Noise still present and behaves exactly the same way.
Could it be the pressure plate on the clutch?

1959 TR3A

 

[CJD]

You already discovered…

When properly adjusted, when you release the clutch, the throw out and pilot bearings are inert and cannot make noise. Neither can the clutch itself.

Your squeak will be found elsewhere. I would look closely at the engine and tranny mounts, the fan belt, the fan, the dynamo, and the exhaust through the cruciform. Anywhere you might have metal against metal, like the clutch cover. Try running without the cover.

 

[malbaby]

I presume that you did not fit a new pressure plate when you changed the gearbox.
Would be interesting to remove the return spring on the clutch slave cylinder so that the throwout bearing is not in contact with the pressure plate when idling and in neutral to see if the noise disappears.

 

[Ariddick]

I did suspect the dynamo and removed the belt but the noise was still present.
That eliminates the water pump and dynamo.
By the way, the squeak is more of a chirp, and gets faster as RPM increases.
I’ll try without the dust cover and also adjust the slave cylinder to ensure throw out bearing isn’t engaged all the time.

 

[Ariddick]

I adjusted the slave rod by shortening it 1 1/2 turns. That should back off the TO bearing if it is rubbing. It was already hot at that time and performed the same, so I’ll test tomorrow.
Once it is hot and chirping, I can go complete idle and the chirping will stop after a few seconds, almost like something slowly stops spinning.
If I press the clutch, it will chirp immediately.
Interesting that also if I don’t press the clutch and rev above 1000 RPM, the chirp will return but as soon as RPM drops lower than 1000, it will go away. I can reproduce that consistently.
If the TO bearing were barely touching, I suppose the higher RPMs could give it enough momentum to turn, but that doesn’t sound right.

 

[CJD]

It’s not your throw out bearing. The TO brg would go silent or rumble (if bad) when loaded by pressing the clutch.

My money is on the clutch cover plate. The crank has about .012” end clearance. When you push the clutch, the crank and flywheel move full forward…twds the cover. When released, the crank is free to move rearward, away from the cover, but can drift fore and aft.

The same applies to the starter motor. It would normally rattle, though, if making contact.

Most importantly, do not remove your clutch again. It cannot be the cause.

 

[CJD]

If you look at the clutch cover closely, you will see it is more complicated than it seems. It must go in just right or it will warp rearward and contact the crank/flywheel. It will not hurt to run the car without it for a while to check.

 

[Ariddick]

That makes sense. I’ll remove the clutch dust cover next. When taking off the cover originally, it did get bent because we didn’t realize it would get caught by the flywheel. I straightened it back but it may be warped some. Process of elimination.

 

[mastaphixa]

John touched on this but I recently battled a squeaking noise that I finally traced down to the exhaust pipe going thru the cruciform area of the frame. Make sure the pipe isn't touching the boxed area and all the hardware for the exhaust pipe mount there is tight. Mine was slightly loose and it created a sound that rang from the engine bay and from under the car. If I hadn't been able to put it up on a lift it would have been much more difficult to diagnose.

 

[sp53]

I would try a stethoscope and listen around the engine. Maybe the dizzy and the timing chain are areas not heard. Is the valve train rebuilt?

Steve

 

[Ariddick]

I tried with a hose but could not locate the source of the noise. I've not yet removed the bell housing dust cover (and plan to do that), but I did get a bit of new diagnostics to add.
Similar that I can press the clutch to produce the chirping when the car is hot, if I am in neutral and idling at stop either on a hill or coasting into a parking lot, the chirping is produced consistently when pressing the brake also. I can immediately let off the brake and the chirping stops and returns immediately if I press the brake.
The brake obviously should have no direct link to the belt or the clutch, but does this possibly support the theory that the crankshaft/flywheel get a load on it and moves forward?
Keep in mind this is while the car is almost stationary, so I am confident this is not brake noise.
The chirping is in sync with the RPM of the engine.
Hopefully the revelation of the brake affecting the noise also makes sense to someone much smarter than I.
Thanks in advance.

 

[mctriumph]

Check the generator, my guess is front the bearing dying
Mad dog

 

[Ariddick]

I did disconnect the belt and confirmed noise was present while generator was stationary.

 

[CJD]

When you hit the brake the crank can move forward...into the clutch cover.

The more you add...the more I am convinced it is the clutch cover?!?

 

[Ariddick]

Perfect. I'll remove that tonight. The brake affecting the noise didn't make sense to me but now it does. Thanks all for your input and I'll update tonight with good news hopefully.

 

[Ariddick]

Well, still a mystery. Removed the bell housing dust cover. There were no signs of scraping or wear on the inside surface. I didn’t like the transmission being open so I made a plastic cover knowing that if it rubbed, metal on plastic would not sound the same. After about a 20 minute drive, noise is back. At idle in garage, can either rev above 1200 RPM and noise is present or press the clutch and noise is present. Not talking about a crank shaft main bearing or thrust washer are we?

 

[mastaphixa]

It might be worth trying to measure your crankshaft float. If for no other reason to take that off the table of possibilities. You mentioned using a hose to try and locate the noise. I have used the blade of a long screwdriver placed on a suspected area of the noise while placing my ear on the handle end. Its sort of like a stethoscope.

 

[mctriumph]

Drain the gearbox oil and look for metal.If you find it the box is toast.
Mad dog

 

[Ariddick]

I'll check end float. As for the gearbox, noise is present in neutral so potentially the only thing that is moving is the input shaft. Since noise is present when pressing clutch or slightly braking while moving forward, I think the issue is forward of the input shaft. Open to ideas though and curious if others agree.

 

[JHaydon]

Drain the gearbox oil and look for metal.

Agree, and I would also suggest the same with the engine oil. I've been thinking thrust washers but hoping I'm wrong. Checking crank end float should also rule that out (fingers crossed).

Another idea: Take some videos of the engine while you work the clutch. Personally I'd start with the engine off, but that may not tell you much. Set the camera at various areas of the engine (front cover/fan, bellhousing, engine mounts, etc) and try to duplicate the noise. This could tell you that it's a combination of things -- excessive end float which pulls the V-belt a little too far sideways, putting a load on the generator bearings maybe??