Clutch cable issues every tank of gas, Clutch adjustment issues Options

[daveandliz]

Hi all,

I'm at a loss to solve this problem (as is the PO, a friend with whom I still talk with and twist wrenches on occasion).

Inga, our 74 1.8 is in need of a clutch adjustment midway into every tank of gas. Initially I suspected a frayed clutch cable (now replaced). The replacement needed to be wound to its max adjustment out of the box, and I've since shimmed it with about 3/8" of washers in addition.

I proposed to Gord (the PO) that it may be the thrust button failing, but he assured me that he would <never> have done the rear main seal (about 10k mi ago) without ensuring the nylon button was not retrofitted with the steel 911 spec part. He's had a dozen + of teeters and I trust this statement.

There are no signs of clutch slip. There is no noise from the release bearing. The pedal box is in good condition and well lubed.

What might be left except for this $5 part? Anyone?

If I pull the drivetrain I'm the type that will get silly on the other details I find. Please stop me before I get silly! Any ideas?

Dave

[mepstein]

Clutch tube in the tunnel loose?

[KELTY360]

Clutch tube in the tunnel loose?

(IMG:style_emoticons/default/agree.gif) Classic symptom of a clutch tube that has broken it's connection in the tunnel. Very common.

[Rand]

Yep, have to agree. There are quite a few threads on this. Here's one that should help you see what might be going on:

http://www.914world.com/bbs2/index.php?showtopic=28313

[Spoke]

Check the clutch tube going from the engine compartment to the interior. Take a pic. If this is rusted and broken, it moves inward every time you press the clutch pedal requiring constant adjustment.

The old cable that you took off, did you pull the cable out of the sheath and check its condition?

[iankarr]

(IMG:style_emoticons/default/agree.gif) 100%. Best to take care of that before you drive it again. When the clutch tube finally breaks free of all supports, you'll need a tow home.

Be safe!

[Dave_Darling]

Yup, time to check the tube in the center tunnel.

Also see if you can inspect the clutch pedal. Where it attaches to the shaft that goes through the pedal cluster, a spiral roll pin holds it to the shaft. The aftermarket bronze bushing kits come with a roll pin that isn't up to the job in the long term. That can result in similar symptoms for a while, until the arm on the shaft runs out of room to move.

--DD

[porschetub]

Mines solid as a rock in the tunnel ,have had to adjust 4 times with rebuilt pedal assembly,NOS clutch,new 914rubber cable roller and new cable from GPR....I wonder whats going on myself.

Oh by the way (IMG:style_emoticons/default/welcome.png)

[BeemerSteve]

Just my 2 cents....went through a gambit of clutch woes until I discovered the real cause. Check the tube entrance at the firewall where the clutch cable goes. Make sure that hasn't torn through because lots of pressure is excerpted at that point.

[daveandliz]

Just my 2 cents....went through a gambit of clutch woes until I discovered the real cause. Check the tube entrance at the firewall where the clutch cable goes. Make sure that hasn't torn through because lots of pressure is excerpted at that point.

Hi Steve (and all),

The tube is good at the firewall, and good (as best as I can see with a mirror) at the front end. There was no signs of fray on the old cable or housing. Once though, the clevis broke on me (another rare fault?) but Gord came to the rescue with a spare. This makes me thing there is some undue friction in the system.... anyone?

I've been there <mit zee most inferior eeenglish gearboxes> but the cross shaft (no cable on) seems free and without any axial play. Gord assured me that the pressure plate and release bearing are all but bulletproof (essentially 911 spec parts) and it was all apart for a main seal change 5 years and 12k mi ago (we have a short driving season). I haven't sworn in German since my imported 1970 BMW 2500 left me a couple of decades ago, but I'm getting close.

I'm also afraid that if I pull the drivetrain that I'll get silly (not Raby silly) and spend my summer in my garage rather than bending the speed limits (I like the optimistic readings... lol).

I should really post some background...

Thanks all, be seeing you...

#6 (I dare you all to catch the reference)

Dave

[IronHillRestorations]

I've seen this same problem when the roll pin for the clutch pedal is going soft.

[dlee6204]

Are you double nutting the cable to keep the nut tight? Or using locknuts?

[Mikey914]

There's always the possibility that the ground strap on the transmission is not making contact. This will make the cable the shortest ground and as current runs through it the metal softens, it stretches and eventually breaks.
This is the easiest fix.

[rjames]

Are you double nutting the cable to keep the nut tight? Or using locknuts?

(IMG:style_emoticons/default/agree.gif)

I was doing frequent adjustments because the PO had a single nut on the cable at the clutch fork.

Even if you have double nuts ( (IMG:style_emoticons/default/blink.gif) ) they may be undoing themselves as one. Easy to check by measuring where they are at on the cable when properly adjusted and measuring again when things need adjusting again.

[TheCabinetmaker]

If the cable has two nuts (adjustment nut, and lock nut)and the lock nut is tight , it will not come loose.

[rjames]

If the cable has two nuts (adjustment nut, and lock nut)and the lock nut is tight , it will not come loose.

It will if you don't do it right:
Bolt Science

[daveandliz]

Hi all,

I'm at a loss to solve this problem (as is the PO, a friend with whom I still talk with and twist wrenches on occasion).

Inga, our 74 1.8 is in need of a clutch adjustment midway into every tank of gas. Initially I suspected a frayed clutch cable (now replaced). The replacement needed to be wound to its max adjustment out of the box, and I've since shimmed it with about 3/8" of washers in addition.

I proposed to Gord (the PO) that it may be the thrust button failing, but he assured me that he would <never> have done the rear main seal (about 10k mi ago) without ensuring the nylon button was not retrofitted with the steel 911 spec part. He's had a dozen + of teeters and I trust this statement.

There are no signs of clutch slip. There is no noise from the release bearing. The pedal box is in good condition and well lubed.

What might be left except for this $5 part? Anyone?

If I pull the drivetrain I'm the type that will get silly on the other details I find. Please stop me before I get silly! Any ideas?

Dave

...for all who replied, here is the update (see a new post shortly). 50 miles into the season the clutch went again. this time when I inspected further there was a tear in the rear bulkhead. I think you all know wha that means... I do (sadly)

[Rand]

Thanks for posting the update. It helps everyone. Likely the failure started in the tunnel, then it gave way at the firewall because of the extra stress. So be sure to repair both places.
(IMG:style_emoticons/default/beerchug.gif)