Triumph Repair: TR7 Heavy Clutch

Question
QUESTION: Hi Howard:

Thanks for your advice on questions relating to my TR7.  I have a question about the TR7 clutch.  I find that the clutch on my car is very heavy.  The car shifts in and out of gears just fine, and drives OK (except for some "jerkiness" due to the heavy clutch).  Is this typical for the TR7?  If there is an issue with this clutch, any ideas on how to diagnose the problem?  

Thanks
Matt
'79 TR7

ANSWER: Hi Matt,

The Triumph clutch is no harder to push then any other straight stick car so if it is hard to depresss then something is wrong and the fact that you say it is jerky to use means it is not a smooth release.

There are several items in the system that can be causing the problem. The peddle itself can be in a bind on the shaft that it pivots on or the master cylinder piston can be binding in it bore. Also the slave cylinder piston can be binding in it's bore. These are all outside but there are things inside the bell housing that can cause the problem too. So you should test everything outside first.

The peddle is easy to check. Just push on it with your hand. It should move freely about an inch before you feel any resistance. The only resistance in that first inch of peddle travel is a light peddle return spring. If the master cylinder piston is sticking in the cylinder bore it will usually scar the cylinder and thus start leaking and you can feel and see fluid runing down the back side of the peddle.

The slave cylinder is a little more work to check. You will need to rmove the long pinch bolt or the two flange bolts from the bell housing and remove the slave cylinder from the bell housing and check inside the rubber boot for excess fluid. A slave cylinder piston that is sticking will scar the bore and make it leak.

If you don't see fluid leaks at either cylinder you can put a phillips screwdriver into the salve cylinder and hold hard pressure in while someone pushes on the clutch peddle by hand very slowly and feel if there is any resistance. Be careful not to blow the piston out of the salve sylinder because some don't have a clip ring to stop the piston.

If all that is ok then the problem is inside the bellhousing. The operanting rod that the slave cylinder pushes on clips into position on the clutch arm and fork. It moves the clutch release bearing slider along a sleeve attached to the transmission. There is no method to lube that slider and BLM didn't make any provisions to lube it so if it is dry the slider can bind on the tube it slides on. Especially if clutch dust form the clutch lining gets on the tube.

It is unlikely the pressure plate as the cause because it is a diaphragm spring and has no way to bind on anything.

Let me know,

Howard

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

QUESTION: Hi Howard:

Thanks for your quick response.  I was just out in the garage and did a check on the clutch master cylinder as you indicated.  When pushing the pedal by hand, you initially meet a little resistance for about 1 inch.  Then the resistance goes way up.  You can push it all the way in by hand but it's quite heavy.  I see no evidence of fluid leakage on the back side of the firewall or the back side of the pedal.  

I suppose the only way to check the pedal bushing is by removing the clutch master cylinder and then moving the pedal by hand.

I will test the slave cylinder as you indicated, but probably not until tomorrow night.  

Thanks again for your help. I will let you know if my findings.

Matt

ANSWER: If you can move the peddle easily by hand for the first inch then there is nothng wrong with the peddle bushing. But if you can push the peddle all the way to the floor by hand I have to question if you have a problem. The few that I ren across that were in a bind and hard to push with your foot could not be pushed to the floor by hand.

Do this, Push the clutch peddle to the floor by hand and let it out slowly to see if the pressure on your hand is smooth and constant as you slowly release the peddle.

Howard

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

QUESTION: Hi Howard:

I tried this latest test.  When I push the clutch to the floor by hand and release, the pressure on my hand is not constant.  The pressure is pretty high at the floor to an inch or two away from the floor, and them is decreases as it further comes out.  

I have not tested anything else at this point.

Thanks for yr help,
Matt

Answer
I don't believe it is the master or slave cylinder if you don't find a lot of fluid leaking.
My guess would be either the bearing slider on the tube is dry or something is wrong at the two side pins in the fork. I would run the little test with the phillips screw driver in the slave cylinder and then if it were my job brought to me in a dealership I would pull the engine and check the slider and side pins.

Howard