Triumph Repair: TR-6 Clutch, linkage components, cross shaft

Question
QUESTION: Howard,

This is in follow up to our recent discussion about a clutch which won't disengage and excessive travel on the pushrod at the slave cylinder. You confirmed my suspicion that there is likely a broken tapered pin which secures the throw out bearing fork to the cross shaft. I worked on the car over the past two nights and removed the gearbox. What I discovered left me perplexed.

The tapered pin was in place but upon removal it was obviously that it was broken. Here's the odd part, the pin wasn't doing anything. The fork has been welded to the cross shaft. I'm guessing that the old pin was only used to orient the shaft before the fork was welded to it. Due to the welds, the fork is still quite secure to the cross shaft, so that rules out the pin as being the cause of excessive pushrod travel and the lack of clutch disengagement.

The fork looks OK as do the the pins which engage the throw out bearing sleeve. Both the sleeve and the throw out bearing look fine.

When I look at the pressure plate, the spring fingers also look good.There are no apparent signs of wear and all the fingers look good.I can't tell from looking if there is fatigue in the spring rate.The clutch is a Borg and Beck "Type 8,  8.5 inch" from what I can gather from the markings on the pressure plate housing.

In any event, I think I can rule out the throw out bearing and it's related linkage components. Is it conceivable that the pressure plate would allow the extent of pushrod movement which I have previously mentioned and still not disengage the clutch?

I'm not sure what the next step is. I can replace the clutch and throw out bearing, but I'm concerned that I'll put it all back together and still have the same condition.

Any thoughts or ideas will be appreciated.

Regards,
Bill

ANSWER: Hi Bill,
That is a puzzle. I would lay a straight edge across the bell housing and measure from that straight edge to the face of the release bearing with the slave cylinder in place and push rod in place and forced all the way in so that the slave cylinder piston is all the way in also.
Then lay a straight edge across the pressure plate on the fingers as flat as possible and measure from that straight edge to the engine backing plate to see how much difference there is. There should not be much difference. That difference is where that slave piston is when the release bearing is just touching the fingers of the pressure plate. If the measurement shows that the piston is half way or more out of the cylinder than something is definitely wrong. don't forget to check the arm that supports the slave push rod to see that it is secured to the shaft. Also that the slave cylinder is mounted correctly on it's mounting plate and that plate is mounted correctly.  

It would be wise to remove the disk and examine it for damage while you have the box out. I did run across a clutch with a piece of clutch lining off and it had doubled up and thus compressed the clutch fingers so the release bearing had to travel excessively to reach the fingers.

By measuring carefully and a close examination you have to find the fault.

Howard

---------- FOLLOW-UP ----------

QUESTION: Howard, Thanks for your advise. I removed the clutch and found that I needed to pry a little bit to separate the pressure plate housing from the flywheel. I subsequently needed to pry against the clutch disc to separate it from the pressure plate. It's conceivable that the disc was stuck to the pressure plate resulting in an inability to disengage. The disc looks OK but the facing of the flywheel and pressure plate are discolored. I wouldn't call it rust but it's like a spotty brown tarnish probably transferred from the clutch disc.

I plan to replace the clutch components and install a new sleeve and throw out bearing and hope that does the trick. I'm still scratching my head as to the cause of the excessive pushrod travel.Would a stuck clutch disc result in additional travel at the interface of the throw out bearing and the fingers of the pressure plate spring?

I appreciate your advise and your speedy responses.

Regards,
Bill

Answer
I don't see the connection but I guess if it was stuck solid to both the flywheel and the pressure plate, and when the clutch was depressed it separated the two linings and warped the lining mounts so as to make it a thicker disk which then would account for the extra needed travel need to contact the fingers of the pressure plate. ?????

I would do the measurements I suggested when you get the new clutch pack before installing the gearbox back in the car.
Howard