adventures in clutch cable replacement

[redstack]

A beginner’s adventures in clutch cable replacement and adjustment
The clutch on my 1984 Carrera was very difficult to depress and modulate. As this is my first Porsche, I wasn’t sure whether this was normal or not. Reading about it on the forums, I got the impression that a Porsche clutch shouldn’t be any more difficult to operate than a clutch in any other car. Advice from the internet said that the place to start was by doing the cheap things first. For example, don’t start with a clutch replacement, because often a simple clutch cable replacement would do the trick. Online the cable was available for only $21, so that seemed like a good first step.
I have the Bentley Manual and 101 Projects for Your 911. I suggest that you read them for complete instructions, but these additional notes from my experience cover some things that they didn’t explain so well. Armed with new set of digital calipers and a metric feeler gauge, I started in on the project. The first day came to a complete halt when I was unable to disconnect the forward cable end at the pedal box. All the information I had said, “It’s tight, but you can get it off.” Well I sure didn’t have any luck. I couldn’t even see the cable end.
After a few days, I went back at it with the idea of trying to come at things from the transmission end. First I loosened the nuts that hold the cable in the bracket on the transmission. Next I was able to slip the hook end off of the throw-out arm. As you can see, it slips off sideways.
The spring on the clutch pedal pulled the cable forward, making the clevis end much more visible. I also found that by unbolting the gas pedal and getting it out of the way, I had pretty decent access to the whole clevis and retaining pin assembly. Fifteen minutes later I was disconnected and ready to pull the cable out. I tried to tie a piece of line to the cable end in hopes that it would help install the new one. One other advantage of using the string is that you should get a better idea of how the cable was originally routed. Of course halfway out, the knot in the string hung up, and if I had had an assistant we might have been able to work it free. Instead I just pulled and lost the string. Oh well.

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I then ran the new cable, routing it the way I believed the original one had been. I couldn’t see the hole where the cable passed through into the cabin. I pulled the rubber boot for the throttle cable back and out of the way, and there was the clutch bulkhead tube. Pushing the new cable in was easy, and the oh-so-important step of seating the cable guide onto the tube was easy as well. I felt it was worth the effort to get the throttle cable boot back on to have a good visual on the bulkhead tube. I believe that the routing of the cable had been wrong before, as I ended up running it above the oil cooler line and the throttle linkage, which gave it a much smoother lead.

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Back at the pedal box end, I was able to feel around and find the cable end. There is also an opening on top of the tunnel that will aid in finding the cable end. Pull back the carpet forward of the shift lever and you can reach down from the top. Screwing the clevis back on the recommended 20mm was easy, and then I made a big mistake. In order to tighten the set screw on the clevis, I took a wrench and put it between the jaws of the clevis and tightened the nut with a wrench. Nice and tight, until I felt a sag in the wrenches. Uh-oh. Looking at the clevis I saw that I had cracked one of the ears. Of course, that brought things to a screeching halt. Don’t do this; just use a wrench in the normal manner.
Once I replaced the clevis, I was able to complete the cable connection with the pedal still lying on the floor. Start the pin in while the pedal is on the floor, then lift the pedal up a bit so you can snap the retaining clip onto the cable from underneath. I wish I could take a photo, but photos of this just don’t show anything.

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In order to give myself enough cable length at the transmission end, I tied the clutch pedal up to the seat belt guide. Before hooking the cable back up, I adjusted the set bolt to a 1.2mm gap as recommended, and then once the cable end was attached, I tightened the cable nuts until the throw-out arm was preloaded to the point that the gap was now 1mm.
Putting everything back together, under the pedals, I was then able to adjust the clutch pedal stop attached to the wooden floorboard so that there was 25mm difference between the length of the cable when released and depressed.
And voila! It was amazing what a difference there was in the pressure needed to depress the clutch. It was so much easier and the clutch engaged much closer to the floor board, which makes driving the car smoothly easier as well.

[85eurocarrera]

Great post. I forgot to take pics before I removed the clutch cable, and was having questions about the routing around transmission cooler as well. Thanks!

[TheSt|G]

Good post, though I'm concerned about your $21 clutch cable. As far as I know, the good option(Gemo or Porsche) are a good bit more than that.

[Miguel Antonett]

how did you remove the pin from the pedal cluster clevis?

[yelcab1]

First, good job.

Second, 20 years ago when I had a 84 Carrera, the clutch was way heavy and changing the cable did not help until I got a new clutch and pressure plate so... you are lucky.

Third, you get what you pay for. That $21 cable will last a few months and pop it goes. You expect to pay about $100 for a decent cable.

[yelcab1]

Originally Posted by Miguel Antonett

how did you remove the pin from the pedal cluster clevis?

The cable end fits into the pedal cluster arm. The clevis pin fits through both the clevis and the pedal cluster arm. The pin has a swing up locking clip that snaps over the round end of the clevis. You push the lock away from the clevis end, swing the clip away from the cable, and remove the pin from the clevis. The clevis slides out from the pedal arm.

Look for a picture of the clevis pin on Pelican catalog and you will see what I mean.