Clutch cable issue - 1982 911SC

trojwl · 06-21-2010, 07:10 PM

The tranny was recently replaced with one from Cog's Cogs in Georgia (big mistake - I DO NOT recommend these people at all).
Also the clutch parts are relatively new.
The problem is that it appears my cable is "stretching" when clutch is applied. The clutch cable has been adjusted by me as per factory manual. But it takes almost full travel of pedal to engage. Adjustments were made under tranny and not under pedal.
The cable was not replaced.
I really don't want to have to spend any more money. For a car whose engine is relatively easy to drop, it sure is expensive to do. I have 36" scissors lift but not the experience to do it.
Am I overlooking an easy fix here (i.e. replacing cable)?
ANY feedback would be appreciated.

Oh Haha · 06-21-2010, 07:15 PM

Replacing the cable is pretty easy. Do it before it breaks and leaves you stranded.

Plenty of threads here that will guide you through the task.

psalt · 06-22-2010, 03:34 AM

This the the first symptom of a failing roll pin in the clutch pedal cross shaft. If the pedal box has never been out, I would pull it out, check the cross shaft amd bushings and replace the $1 pin.

Peter Zimmermann · 06-22-2010, 08:36 AM

It is also a symptom of a breaking throw out bearing release fork. Engine removal required. But first a re-print of one of my earlier posts...

Clutch cable removal – 1977-1986

1. Place the car in the garage so that you have room to open your driver's door, if not all the way at least most of the way.

2. Jack up the rear of the car until the bottom of the tires clear the floor by a few inches (you want enough room so that you can get under the front transmission mount plate). Set the car firmly on axle stands and the put your jack under the belly of the car for extra protection. I use a 1' x 2' piece of 3/4" ply between the jack and car, and place the wood so that it's under where the horizontal part of the floor changes to vertical (just forward of the trans mount). Now the car won't fall! Of course, if you have a lift, use that!

3. Remove the pedal board carpet, driver's floor carpet, and the pedal board. To release the gas pedal simply grip it firmly at the top and pull straight back - it'll pop off its rod. Pull the board away from the pedals. FYI: Do not attempt to remove the center console for this repair.

4. Go under the car with two 15mm open end wrenches, 2x flat-bladed medium screwdrivers, 1x large flat-bladed screwdriver or medium pry bar, and a snap ring pliers that works on retaining rings with small holes in the ends. Locate the omega spring under the diff housing, along with the long arm that it attaches to, and a short arm whose end seats against the end of an adjustment bolt. Remove the snap ring holding the short arm, pull the arm straight down and set it aside (you might need a couple of flat-bladed screwdrivers for this).

5. Use your 2 wrenches to loosen the cable nuts on the back end of the clutch cable bowden tube (at a small aluminum anchor that’s attached to the differential housing side cover), pull the bowden tube away from the mount.

6. Use your large screwdriver (pry bar) to release the tension on the big cable arm by pushing the arm toward the front of the car. It will happen quickly because of the omega spring tension, keep your fingers out of the way.

7. Unhook the cable from the long arm (you can pull the arm down or just leave it there, but if you leave it be careful, it might fall off and hit you on the head – early arms have a locking pin, later cars don’t). FYI: The short arm fits onto splines, the larger arm floats on a smooth part of the throw out bearing fork shaft. If you remove the long arm clean it before installation and put a thin coat of moly or lithium-based grease on the shaft. If the omega spring requires replacement the long arm must be removed. On long arms with a securing pin, the pin must be driven out using a punch and hammer (difficulty factor can range from medium to very hard depending on rust/debris).

8. Go back inside the car (head first under the steering wheel/column), push the clutch pedal to the floor (it might already be there), and locate the clutch cable clevis pin and fork. Rotate the pin until you can remove it (it might be a real pain to take out depending on wear – you might have to use a small punch and hammer, different types of pliers, etc., or it might just come out easily). Once it's out pull the end of the cable, with clevis fork, out of the tunnel far enough so that you can use 12mm and 10mm open end wrenches to loosen the jamb nut. Unscrew the fork and nut all the way and set them aside for cleaning.

9. Go back under the car and look up between the forward side of your front transmission mount plate and the firewall forward of the nose of the transmission (you might have to move your jack and safety board a little). Locate where the clutch cable bowden tube connects to the firewall, put a flat-bladed screwdriver under its edge and gently pry it loose toward the rear of the car.

10. Grab the cable and pull it out of the car from under the back of the car; have a couple rags handy, it'll be greasy.

What you need to know:
A. With the cable on the workbench hold the bowden tube with one hand and pull the cable through it toward what would be the back of the car. Does it move smoothly? Any broken strands?
B. What is the condition of the arm and bushing where the clevis fork/pin attaches?
C. Is the black helper spring on the left side of the pedal cluster, for the clutch pedal, intact?

One tip before you order parts. Aftermarket cables are available, but they are no good. An o.e. cable costs about $85.00, the other about $30.00. Trust me, use the o.e. unit.

trojwl · 06-22-2010, 08:38 AM

Have ordered new cable and will address pedal cluster issues during replacement.

trojwl · 06-22-2010, 08:40 AM

Peter, thanks also to you.

Peter Zimmermann · 06-22-2010, 08:56 AM

Quote:

Originally Posted by trojwl

Peter, thanks also to you.

You bet, and don't forget (from above)...

"One tip before you order parts. Aftermarket cables are available, but they are no good. An o.e. cable costs about $85.00, the other about $30.00. Trust me, use the o.e. unit."

Jdub · 06-22-2010, 10:00 AM

I second Psalt on the retaining pin at the pedal box. I would HIGHLY recommend you pull the pedal box and rebuild with brass bushings available from our sponsor. At the same time, replace the trunnion and the lock pin used to secure the cable at the pedal box end, within the tunnel. The difference in a rebuilt 'box is amazing - you can push the clutch lever down with your pinky!

Peter Zimmermann · 06-22-2010, 11:24 AM

Quote:

Originally Posted by Jdub

I second Psalt on the retaining pin at the pedal box. I would HIGHLY recommend you pull the pedal box and rebuild with brass bushings available from our sponsor. At the same time, replace the trunnion and the lock pin used to secure the cable at the pedal box end, within the tunnel. The difference in a rebuilt 'box is amazing - you can push the clutch lever down with your pinky!

I cannot recommend brass bushings, especially for a street-driven car. In many cases, when brake fluid begins to leak from a master cylinder, the factory bushings become contaminated, and gradually will swell up. When that happens the operation of the brake pedal becomes stiffer, and will eventually stick in the on position, requiring a toe under the pedal to pull it back. So, factory plastic bushings become a great warning system.

My second reason is that I've done repairs to pedal assemblies fitted with brass bushings, and the metal to metal contact caused some irreversible damage to expensive pedal assembly parts. I've done pedal assemblies with 300K miles, and plastic bushings, and nothing but the bushings needed to be replaced.

Always prepare to replace the clevis pin and the bushing for the pin. A worst case scenario is when the pin has worn away the bushing and then damaged the clutch pedal shaft, which will make a pedal cluster rebuild mandatory - including replacement of the dreaded roll pin!

Jdub · 06-22-2010, 02:25 PM

PeteZ and all: First I have heard of the brass bushing problems - would think that unlike metals would cause the weaker (read: brass) to fail firstmost, so a bit confused having rebuilt many Amal carb bodies over the years... But take your advice as you find it.

And so true about the brass bushing, about 1/4" diameter, that, when it fails, puts the pin direct against the "ear" of the clutch pedal mechanism. Be sure to include that in your rebuild!

Peter Zimmermann · 06-22-2010, 03:16 PM

Quote:

Originally Posted by Jdub

PeteZ and all: First I have heard of the brass bushing problems - would think that unlike metals would cause the weaker (read: brass) to fail firstmost, so a bit confused having rebuilt many Amal carb bodies over the years...

I always thought that too, but I think the wear issue occurs with metal transfer; soft to hard, and then tearing of the steel follows. I guess that I should have, at some point, had an analysis done. I ran the brass bushings in my race car, but as soon as the pedal assembly got dusty we'd take it apart, clean, lube and inspect everything, and put it back together again.

trojwl · 07-26-2010, 12:22 PM

Just finished replacing all old nylon bushings with brass types. This solved the clutch linkage "travel" problem. Now shifts better than ever.
I don't think you can even get nylon ones. Besides brass seemed to be the more logical choice.

One question though...
How do you get the clutch assist spring on cluster after cluster is bolted to floor? That is one tight spring. Is there a quick and dirty on this??

Oh Haha · 07-26-2010, 01:36 PM

I installed mine on the workbench.

Check this out for more info-http://forums.pelicanparts.com/porsche-911-technical-forum/159061-dreaded-clutch-pedal-return-spring.html

trojwl · 07-26-2010, 02:53 PM

I figured an amazingly simple way to install spring. No vice grips, no come-along. I just submitted a new thread in the forum with explanation and pic.
It took less than half an hour.