Clutch Action - Taper Pin

[Percy TR6]

Having experienced a somewhat notchy engagement in first gear for a while, I recently checked the gearbox and discovered the alignment dowels were missing. Having installed dowels I also took the opportunity to remove excessive play from the clutch mechanism - new bushes on the pedal and an adjustable rod on the master to take up slack caused by wear in the pedal.

 

Engagement is now much better and I can pull away from the lights smoothly. However, the clutch will only fully disengage at max pedal travel - and even then, only if I connect the slave at the top hole. Its only a problem in first and reverse, but its a problem nonetheless an needs to be corrected.

 

Having read through other posts on the subject, I am being led to a supposition that the taper pin may be broken. Unfortunately, it seems that I will need to remove the gearbox in order to get to it. Joy of joys!

 

Given this, I am throwing this out there to see if there is anything else (more accessible) that I might have overlooked?

 

Both master and slave are relatively new and leak free. I have checked for excessive play at the master and cannot see any. Fluid is also new.

 

Thanks in advance,

 

Steve

[ed_h]

Steve--

 

This is a known weakness on the TR6. If it's never been addressed, the pin is very likely broken. A broken pin can cause the symptoms you describe.

 

Since it's really a design problem, just replacing the pin isn't enough. The yoke attachment to the shaft needs to be enhanced. Many people add a supplementary pin or bolt. There is one approach described here near the bottom of the page: http://bullfire.net/TR6/TR6-23/TR6-23.html

 

Ed

 

Edited January 18, 2016 by ed_h

[TR 2100]

Broken pin is a possibility

But

First check that your slave cylinder is fitted on the

correct side of the bracket

(although if you have incorrectly fitted an adjustable

pushrod, you may have alleviated any problem)

and that

The bleed nipple is at the top of the slave cylinder.

 

Do you have a return spring?

 

AlanR

[TriumphV8]

There are many more reasons for the clutch to fail:

 

1.) New parts are no guarantee for reliable work. Just had to open 3!!!! master

cylinders that all had bulged rubber parts and did not work reliable. We changed

to old Girling parts I had at hand and all was well again!

 

2.) There are two different masters, the 0.7" and the 0.75". Triumph had swapped

to the bigger ones because they knew about that problem with the travel way for

the price of higher pedal forces.

 

3.) Besides the weak points in the mechanic that are aleady mentioned the clutch

itself can be the culprit. If one of the three items what is the flywheel, pressure plate

and clutch plate is uneven the clutch will stick. Mostly the clutch plate is the culprit,

next is the spring of the pressure plate.

[Percy TR6]

Thanks for the input guys.

 

ALANR: the slave is on the correct side of the bracket; the bleed nipple is at the top; I don't have a return spring fitted. The adjustable rod is at the master cylinder to take up the slack caused by wear in the hole in the clutch pedal.

 

Given the comments so far, it would seem all to point at bits that live behind the bell housing, so it will be off with gearbox when the weather warms up a bit I guess.

 

Steve

[RogerH]

Hi Steve,

if the standard taper pin is broken then replacing it will give you another 50K miles.

Most people fit another pin/bolt at 90' to the original. The item in post #2 is very nice but a parallel bolt/pin will also do the job 3/16" diameter or so.

 

Many moons ago TRShop in London were selling forks that had the correct taper hole continuing past the shaft that put the taper pin into double shear and this works a treat but no longer available as far as I can see.

 

On my other car (TR4) I fitted a bush in the area of the fork the other side of the shaft and machined the taper pin to have a parallel nose to fit the bush.

This will work but is overkill.

 

Roger

[foster461]

You can often diagnose the sheared pin condition by disconnecting the slave rod from the shaft and then push the shaft lever all the way forward as far as it will go. Then pull the lever back gently until you feel/hear the release bearing hitting the clutch. If the pin is good, as you continue to pull the lever back you will feel the resistance as the release bearing tries to depress the clutch fingers. If the pin has sheared you will feel/hear some slight resistance as the bits of the pin align but the lever will continue to move further backwards as the fork rotates on the shaft.

 

Stan

[Percy TR6]

Thanks for that insight Stan - I'll give it a go as soon as I can get back into the garage.

 

Steve