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Discussion Starter #1
I’ve been having trouble the clutch in my ‘74 spider not fully disengaging. A few weeks ago you could get it to shift if you buried the clutch pedal to the floor but now that doesn’t even work. With the car at idle, you can’t get it into any gear not even reserve without grinding. You can hear that the input shaft of the trans is still spinning at engine speed even with the clutch fully depressed… so it’s pretty clear that it’s not fully disengaging.

There was no air in the line, no leaking from either the master or the slave cylinder, and I was getting a good ¾” of travel in the clutch fork when I measured it with someone in the car pressing on the clutch pedal. There was just no adjustment I could put into it to get the clutch fully disengaged, so I bit the bullet and pulled the trans hoping that something in the clutch mechanism would be the obvious cause. However, despite being a little old and dirty there is nothing obviously wrong with the clutch. The disk still has some material on it (7.75mm thick) and the Sachs pressure plate doesn’t look bad either. Even the throw out bearing looks dirty but decent. I didn’t see anything obviously wrong with the pilot bushing or its mating surface on the input shaft either. Now I’m stumped. I can throw a new clutch in while I have everything part but I’d love to diagnose the actual problem before I start just blindly throwing parts at it. Every time I try and fix something that way I just end up spending money, putting everything back together and the problem is still not resolved. Do pressure plate fingers get fatigued and eventually fail to back the fiction surface away from the disk? Any ideas?
 

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Richard Jemison
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7,377 Posts
Clutch

Common problem. The lever that is attached to the clutch`s pivot rod (just behind the MC) that moves and presses in the MC is only "Butt" welded and twist loose.
Easy fix.
Pull the clutch petal up to the normal height (next to the brake petal).
Then grind the top of the short lever down exposing a portion of the pivot rod. then weld up that area again.

If that isn`t your problem replace the MC. If it`s not making pressure however there should be leaking at the rubber bellows where it seals to the push rod.

The clutch system also has to be bled at the line entering the MC.
 

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Discussion Starter #3
I read about that issue when I did a search on the forum but it looked like the weld on my pivot arm was fine. Is it possible that from the left side (the outside) of the pivot arm the weld looks good but in fact the position of the arm relative to the shaft that connects to the clutch pedal has changed? Oh man... if that's true I wish I realized that before I pulled the tranny. But, live and learn I guess. This spider is still infinitely more enjoyable to work on than the Porsche 928's I had before so it could be worse, I could be working on a Porsche.
 

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I have had the same problems with both 4 cylinder cars and Milano cars. The problem was a worn out pressure plate. The clutch plate still looked good, but the pressure plate fingers were worn out and had to be replaced. I usually get 100,000 miles clutch life for either a four cylinder car or a Milano. I have a Milano clutch that still looks good, but the clutch will not disengage.
 

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Discussion Starter #6
...The clutch plate still looked good, but the pressure plate fingers were worn out and had to be replaced. I usually get 100,000 miles clutch life for either a four cylinder car or a Milano. I have a Milano clutch that still looks good, but the clutch will not disengage.
Ok, thanks. That's great feedback.
 

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Yep, it's the pressure plate. The 3/4" of travel you measured at the clutch slave fork tells you everything you need to know about the clutch hydraulics & the clutch arm at the master.

Had a car in a couple of years back where everything was fine with the hydraulics; so I sold him a clutch replacement. My heart sank when we got the gearbox out because the clutch looked brand new, & the owner confirmed that it was only a couple of years old. However, when I placed the new pressure plate next to the old one, the new one sat significantly higher. Also, my machinist found that the step in the flywheel was out of spec. With the new clutch & a properly machined flywheel, all was well.

On the flywheel, a 2.0 flywheel that is, the step from the clutch cover's mounting surface to the clutch disc's resting surface should be 22.5 mm with a tolerance of +0.2 mm. Note, that's only plus 0.2 mm, not minus. That's intentional as the step should not be any less than 22.5 mm. On every clutch job, I have my machinist measure the step, rather than simply removing the same amount of material from both surfaces.
 
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