Mechanical Clutch question...

[Don Becker #41636]

Hi all,

I test drove a 76 4 speed this weekend. Totally loved it, but I was told that it has a mechanical clutch.

The pedal was the hardest clutch I've ever felt in my life. I've been told that it can be adjusted, is that true? Can I modify it to not be so heavy?

What's the difference between a mech. clutch and a hydraulic one? If I can't modify the mech. clutch to be lighter, can I replace it with a hydraulic clutch?

How hard a swap is that? Any estimate on cost?

[Jim T.]

Re: Mechanical Clutch question...

Don the 76's clutch may be the hardest clutch ever felt in your life because you had never driven a car/truck with a mechanical clutch. Hydraulic clutchs and hydraulic brakes operate basically the with same type of power applicator, the clutch master cylinder or brake master cylinder. Can you imagine stopping a car with mechanical brakes? The mechanical clutch in your 76 may seem to require more pressure application from you because there is no hydraulic assistance. Several areas require lubrication in a mechanical clutch. Perhaps a good cleaning and lubrication of the mechanical system will help. The pressure plate may be the only reason that the operation is hard for you. The owner or previous owner could have installed a type that requires more foot pounds of effort to function. This can be easily changed with a new OE type system and a through cleaning and lubrication of the system. You can modify the car to a hydraulic clutch system but I don't think I would do it. Sometimes a stiff clutch, or even a mechanical clutch that operates correctly will keep some people from wanting to drive "The Corvette". There are many posts in the archives on what are considered the best OE type replacement clutch replacements.

[Don Becker #41636]

Thanks Jim, here's another question...

Hi Jim, thanks for replying.

I used to have a '66 mustang with manual brakes, so I can understand you there.

I think what seemed to intesify the problem is that the fiancee has started making me run with her 3-5 miles a day.

Although my left calf hurts considerably more than the right...

BTW I need a good book/shop manual on checking the underside of this 76 on a rack. Can you suggest a good one?

[Gary S.]

Re: Thanks Jim, here's another question...

Don, visit the NCRS store at https://www.ncrs.org/store/shop.cgi/...094565326.1862

I would buy the Judging Manual for your car and the GM Service Manual for a start.
Gary

[Don Becker #41636]

Re: Thanks Jim, here's another question...

Thanks Gary!

BTW, do your recommendations have the body mounts and other frame components?

Since this is a 30 year old car, I'm kind of nervous about my mechanic having enough info to check for possible troubled areas before I own the trouble so to speak.

[Gary S.]

Re: Thanks Jim, here's another question...

The manuals I suggested are the reprint of the GM Service Manual. While I can't state whether or not body mount information is in there, most of what an experienced mechanic would check while underneith the car is intuitive or, at the least, fairly obvious. Do a search of the archives and read the volumes on frame issues dealing with rust etc. I personally have not experience or history with a rusty frame.

Gary

[Jim T.]

Re: Thanks Jim, here's another question...

The 76 Corvette service manual should have body mount information. The manuals I have for 63-64, 69 with 70 supplement, and 71 Corvette service manuals that have body mount information. The 68-72 Corvettes have solid body mounts and the 73-82 have rubber body mounts.

[Michael H.]

Re: Mechanical Clutch question...

Hey Don -

I converted my 63 roadster to hydraulic clutch and it worked great. I wrote an article about the conversion that appeared in the April 2004 issue of Corvette Enthusiast magazine.