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Triumph Repair/TR7 Heavy Clutch Continued Again

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Question
Dear Howard:

Thanks for all your continued assistance with the clutch issue on my '79 TR7.

The car is at my mechanic for clutch work.  The transmission is out and I've examined the old clutch.  The disc is worn but not overly so.  There appears to be black marks on the disc and the disc material is discolored compared to a new disc.  The pressure plate looks ok, no anomalies.  The release bearing slides smoothly on the tube it rides on.  

The only issues found were some leaks in the transmmission, and the rear transmission mount is worn out (replacement is on order).

I was wondering if you had any other ideas.  I'm beginning to think that my car simply has a heavier clutch than other TR7s of similar year.

Thanks for any help,
Matt

Answer
Hi Matt,

Black marks on the disk if they are smooth and glossy are usually an indication of excessive clutch slipping. This is common in a lot of city driving, especially if the driver sits at a light with the car in gear and the clutch peddle depressed. All of my experience with BLM was in Jacksonville, FL so I seen the results of city driving. Because of the carbon release bearing in the MG's I always reccomended to put the car in neutral at lights. Even though all TR-7's had a ball bearing release bearing by using that practice on the TR-7's it also tended to extend the life of the clutch and hydraulics, so I told TR-7 owners to use that same practice. However it does require that you keep the engine tuned and set at a low idle and use a 1 to 2 second delay after depressing the clutch an engaging first gear from neutral or you just trade ware on the clutch system for ware on first gear syncro in the transmission.

As far as a hard peddle pressure I never measured with a scale how hard the peddle was to push, other then I often checked the hydraulics by hand pushing the peddle down.

The only other thing I can think of is, even though the bearing slider is free moving without a load it can still be a problem under load if it is dry and no lube on the slider. Remember that the fork that moves the slider moves in an arch thus it puts a very high side load on the slider in it's travel. So be sure there is lube on the inside of the slider.
Read my tech tip on haoe to extend the life of a gearbox which also applies to a clutch too. http://mg-tri-jag.net/tech4.htm

Howard  

Triumph Repair

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Howard M. Fitzcharles III

Expertise

Triumph TR-4 up & Spitfire, and Engine theory

Experience

Dealership line mechanic on MG, Triumph, Jaguar for 15 years, Instructor in commercial mechanics school 2 yr. Product information manager for piston and valve manufacture, Instructor & hotline answer man for import car parts importer 15 yrs.

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Associate member SAE EAA member

Publications
Import Car magazine

Education/Credentials
ASE Master Auto with L-1 certification up to 2000

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