TR6 TR6 clutch noise

[Flummoxed]

Guys-
You've always been a tremendous help to not so much of a mechanic guy like myself. I have a 73 TR6, my concern is that I have a slight clutch noise (similar to that mechanical sound a worn speedometer cable may make)while in neutral. This sound goes away when I step on the clutch. Mostly, the car shifts nicely into all gears. But, maybe only a slight hesitation in shifting into second when cold. I do know my gearbox and motor mounts are pretty worn (if that's a possibility for this noise prob.)Can anyone lend some ideas? Thanks.

 

[Brosky]

There will probably be plenty of comment on this, as it is and age old problem with TR6's in general.

I believe that your throwout bearing is making the noise as it slightly contacts the spinning pressure plate. You might try adding a spring to pull back on the lever so that it doesn't touch when sitting in neutral.

I know that the spring in the slave cylinder is "supposed" to do this, but it may be getting weak and it obviously is not.

Please take this under advisement only, because diagnosing a noise from 3,000 miles away is not yet an exact science.

 

[DougF]

Your clutch is ready for replacement. If the throw out bearing is going, I would replace everything so not to have to go back in any time soon. While it is out, check the tranny for wear.
It could last for a while, depending on how much and the type of driving you do.

 

[TR6oldtimer]

There will probably be plenty of comment on this, as it is and age old problem with TR6's in general.

I believe that your throwout bearing is making the noise as it slightly contacts the spinning pressure plate. You might try adding a spring to pull back on the lever so that it doesn't touch when sitting in neutral.

I know that the spring in the slave cylinder is "supposed" to do this, but it may be getting weak and it obviously is not.

Please take this under advisement only, because diagnosing a noise from 3,000 miles away is not yet an exact science.

Actually the spring the slave cylinder is designed to apply enough pressure to keep the throw out bearing engaged with the pressure plate and constantly in motion. Many of the new "replacement" throw out bearings are stiffer then the originals and can cause problems.

Hopefully others can recommend the best part.

 

[TR3driver]

Does the noise go away when you only lightly rest your foot on the clutch pedal ? Or do you have to fully disengage the clutch to make the noise stop ?

If it's the latter, the center bearing in the gearbox (between the input and output shafts) may be failing; and should probably be attended to sooner rather than later. Eventually it will ruin the shafts as well and they are kind of expensive.

If it's the former, then I agree it's most likely the TOB, and it can't hurt to try adding a spring to put a little more force on it.

 

[Brosky]

It also could be the pilot bearing spinning around in the back of the flywheel. I would try Randall's spring first as I suggested, since it's the easiest and doesn't require pulling the transmission to let you know if it helps or not.

After that, what the others say could be true and you will have to pull it apart to see exactly what's wrong.

Again, we're all guessing from afar, but these are educated guesses.

 

[RonMacPherson]

Randall,

did the 3's mount their clutch slave cylinder like you have pictured?

Every six is supposed to have the slave on the tranny side of the bellhousing. Maybe it's just the way I'm looking at the picture...


Also, a bit confused on what you mean as the "center" bearing.

Are you talking about the needle roller that rides on the inside of the input shaft?

Reason I ask is the Bentley manual language is not what the industry currently uses. What they call the "centre" bearing is called the input shaft bearing, here on the North American continent.

 

[TR3driver]

Ron,
That is not my photo, but snagged from an article written by Nelson Riedel and originally posted on the Buckeye Triumphs web site. I believe it is of Nelson's 76 TR6, and since I know him to be a very capable and careful engineer (not to mention a great technical writer), I think it's probably correct. I believe he got the idea for the spring from Joachim Gunst, the turnbuckle for adjustment was Nelson's addition.

At any rate, on a TR2-4, the bracket would be on the rear (transmission) side of the flange, then the slave cylinder would be on the engine side of the bracket. Meaning you can remove the slave from the bracket without disconnecting the hydraulic hose. That is the only way it will fit on a TR2-4, because there is no engine plate to cover the lower part of the bellhousing opening, and the factory plate to close the opening has a lip on it.

The TR6 Haynes I have, as well as the factory TR6 SPC, show the TR2-4 configuration; but the TR6 owner's workshop manual shows it as above. I actually believe either configuration would work; but since I have very little direct experience with TR6 (only Stags and the TR6 parts that will fit a TR3), I don't know that.

Yes, by "center bearing" I mean the needle roller that rides inside the end of the input shaft, with the output shaft in the center. When I bought my first Stag, it had exactly that symptom and that failure. Root cause, I believe, was lack of the special "dowel bolts" with precision ground 3/8" shanks that are supposed to do double-duty as both bolts and locating dowels between the bellhousing and engine rear plate (or casting on a Stag). Without the dowel bolts, the transmission slips out of alignment with the crankshaft and forces that little needle bearing to run at an angle, which overloads it.

Sorry if my terminology isn't quite right. I get confused trying to use American English to describe a British car; so I tend to make up terms on the fly. To me, the "input shaft bearing" would be the ball bearing that carries the input shaft in the front of the transmission housing.

PS, I don't think the pilot bearing is likely to be the source of the noise with the clutch engaged, since it only turns when the clutch is released.

 

[Brosky]

Sorry that I don't have a better view of it, but this is my spring arrangement. I did have the Gunst bearing in mine and this is the opposite setup. I do not have additional pressure on the bearing to plate, but rather to keep the bearing off of the pressure plate.

Randall, while I don't disagree with you, I have found pilot bearings to make noise at the oddest times, so I always check them when the transmission is out.

 

[TR3driver]

If you do reverse the spring action as Paul shows, you should also convert to an adjustable pushrod. The original spring is what provides the "self-adjusting" action; and simply forcing the pushrod into the slave will result in excess freeplay unless you also add an adjustment for freeplay. Which of course will then need to be adjusted from time to time.

Either one will work, but Paul's setup increases freeplay at the pedal, reducing overall travel (and the TR6 clutch mechanism has no travel to spare); and also allows the TOB to slip against the PP for just an instant each time you depress the clutch (which can sometimes cause an annoying chirp). Some folks find these shortcomings objectionable; but that's the way I setup my TR3A (with the TR6 clutch and transmission) and it worked fine for me.

 

[Flummoxed]

Thanks for the help. Randall, the noise completely goes away with the clutch pedal depressed approximately halfway.

 

[Brosky]

Sorry, my bad. Randall is correct. I do have the adjustable push rod!

 

[TR3driver]

the noise completely goes away with the clutch pedal depressed approximately halfway.

In that case, I think most likely you have a problem inside the transmission. Might be the bearing I mentioned above, or possibly could be the layshaft (countershaft) bearings; since they all turn with the clutch engaged and gearbox in neutral, but stop when you disengage the clutch.

But of course that's still a guess.

 

[Brosky]

Oddly enough Randall, that's exactly how two of my Gunst T/O bearings acted and why I replaced them. Again, it was on the B&B Pressure Plate and not the Luk, which is a whole other subject.

Anyhow, here is the adjustable rod, right before we installed the spring.

 

[Flummoxed]

Btw, here is a link for a sight w/great pictures on this matter.
https://www.74tr6.com/clutchreplacement.htm

 

[Brosky]

Ah.... that's my site.

Thanks!!