Triumph Repair: TR6 Clutch sticky at bottom of travel

Question
QUESTION: Hi Howard;

You helped me before with a fast idle problem on my '76 TR6 so I'm hoping you can comment on a new issue that has come up.  When the clutch pedal is fully depressed and I go to release it in 1st gear, there is no movement until there is almost no foot pressure and then it wants to jump to the release position.  I have to keep the rpm's up to get going or the car ends up stalling.

Would you suspect a hydraulic problem in this case or something mechanical in the clutch itself?

Do you have any suggestions as to how I might narrow down the possibilities before get into a costly clutch replacement?

Thanks,

John

ANSWER: Hi John,

There are several things that can cause that. The TR-6 has a large shaft that runs all the way across the bell housing and that shaft could be sticking. Other things to look at are, the clutch pedal itself can stick on it's pivot and it can be in the hydraulics, a sticking piston in the slave cylinder or even a sticking piston in the master cylinder. Another possible is that you have a diaphragm type pressure plate and it is over compressed which makes the diaphragm spring very weak when close to full retraction.

I would start testing by depressing the clutch by hand with the engine off. Depress the pedal slowly and note how hard it is to move each 1/4 of an inch at a time until you have it fully depressed to the floor. It should be free moving for the first inch then it will be firm and hard to push. It should be also about the same resistance as you move it a quarter of an inch at a time all the way to the floor. If it becomes very easy to push when close to the floor then I believe you have a pressure plate problem.

In the travel note if the pedal seems sticky meaning it is hard to depress the last inch or so but if you stop moving it then it is easy to hold steady but hard to depress any further. This is an indication of one of the items above it sticking. This is easy to test by just removing the clevis pin from the slave cylinder operating rod and by hand move each component to see if any are binding. The lever on the shaft going through the bell housing should feel free moving and you can operate the lever which slides the release bearing back and forth. Sometimes the slider that supports the release bearing gets dry and rusted and will not slide back and forth freely. Or the bearings in the bell housing will bind up on the shaft making it stiff to move.

When checking the movement of the pedal and hydraulic pistons be sure to only move the pedal one time before depressing the slave cylinder rod back into it's bore. Some slave cylinders had a lock ring to prevent the piston from coming all the way out but some do not and if you push the clutch pedal down more then once, without pushing it back in, it will pop all the way out and blow fluid all over and blow the piston and seal out too.

Some where in those tests you will find the problem. Let me know.

Howard

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

QUESTION: Hi Howard:

I did a bit of checking on manual pushing of the clutch pedal.  The pedal seems a bit softer a the bottom of travel but I wouldn't say that it's "easy" to push the last couple of inches.  I did notice while I was under there that there is some brake fluid pushing back through the master cylinder dust cover under the dash.  I would guess that this indicates a problem with the seals in the master cylinder so I will start there.  I haven't gotten under the car to check the slave cylinder travel yet but will do as a next step.  Thanks for the suggestions - I am hoping to find a fix that doesn't involve pulling the transmission unless absolutely necessary.

Happy Thanksgiving,

John

Answer
Hi John,

The fluid leak at the master cylinder may or may not be related to your problem but the master cylinder must be either rebuilt with a kit or replaced when it shows signs of leakage. In the dealerships we found that it is a good idea to repair or replace both the master and the slave cylinders together as every time one is failing, it is not long before the other fails too. So it became a necessary policy in the dealerships to do both at the same time and always use DOT 4 fluid.

Even if you still have an internal problem with the clutch itself the cylinders need to be corrected.

Unless you are experienced at rebuilding master cylinders and have the tools, we always recommend replacing both. It will save you a lot of trouble in the long run. These parts are still available from companies like Engel Imports, Moss Motors, British Victoria and British Parts Northwest to name a few and all have toll free numbers to call for price and availability. I have had dealings with all four and they are reputable companies.

Howard