Stretched Clutch Cable - 1983 SC

[Gordo2]

Last weekend I noticed that my clutch wasn't fully disengaging when the clutch pedal was pushed all the way to the stop. With the clutch depressed, you could feel the vehicle attempting to inch forward, and shifting became difficult.

I recently rebuilt the transmission, but I didn't replace the clutch cable - for all I know, it's original (my 1983 SC has ~ 220k miles on it).

When I installed the rebuilt trans and adjusted the clutch, I noticed that the clutch cable didn't seem to have much life left - to get a 1mm gap, the locking / cable mount nut was barely threaded onto the cable tube. Meanwhile, I was still able to adjust it to spec, and the clutch engaged / disengaged fully and the trans shifted fine - so I didn't bother to replace the cable.

Photo of the old cable - tightening the leftmost (nut threading / moving toward the back bumper) would decrease the gap from 1.2mm down to 1mm, but only a few threads remained exposed to thread the rightmost nut (the nut that cinches the cable to the transmission mount)



I ordered a new cable this week (Gemo brand seemed to be recommended).

I also removed the old clutch cable to inspect it. Although the clutch cable appears to be a pretty heavy gauge wound wire cable - I found sections that clearly appeared stretched / distorted.

Photo of a normal clutch cable section showing how the windings should look:



Photo of a section of the clutch cable that shows stretching / distortion of the windings:


In addition to the visibly stretched windings, the rubber casing on this section of the cable also appeared rusty - with the rust emanating from the inside of the casing / coming from the cable. I only inspected a small section of the cable (I didn't remove the opaque sheathing) so it's possible that there could be more areas of the cable that have stretched.

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I'm reasonably confident that the streched cable is the source of my problem.

- I've inspected the pedal assembly and pin that holds the clutch pedal to the shaft. Everything appears to be in working order.

- The clutch arm (the one that adjustment bolt contacts) felt solid and was in a normal position (i.e. able to be adjusted to 1.2mm gap). As such, I don't think that the throwout bearing / clutch fork is broke (or at least I hope not).


Will follow up when the cable arrives.

Gordo

[juanbenae]

the cable keeper on the trans mission is a replaceable part as I'm sure you are aware. they get distorted and hogged out after all these years of adjustment. sometimes replacing the tranny keeper will buy you some time with a stretched cable... like 500 miles.

[billybek]

Mine started stretching right before it broke. Had done several adjustments and it wouldn't stay adjusted very long.
It broke when I was about 50 miles out of town.

[Walt Fricke]

My experience is that cables don't really stretch. Instead, they fatigue at the swedges - where their end pieces are crimped on. First there is just one wire broken right at that point, because that is where the stresses are greatest. From there it is sort of exponential, as more wires break until the end fitting breaks completely off.

At least that was the case with my V@ beetles and bus. My 911's broke where the cable passes through the firewall - somehow the Bowden tube had gotten dislodged from the steel tube welded to the chassis, and the cable rubbed on bare metal until it broke. Obviously not your issue.

But maybe some engineer with cable experience knows about cable stretch?

I take it that the clutch disk was fine when you rebuilt the transmission? Or didn't you pull the clutch pressure plate? As the clutch disk wears, you have to keep loosening things, if I remember when I wore a disk down to the rivets.

I also once failed to use proper care in setting up the clutch attachments and had to put my foot all the way to the floor to disengage despite close to zero play on the adjusting screw. Someone noticed things didn't look right, and by adjusting per the factory specs and moving the short arm one tooth all was back to what it should be.

[juanbenae]

Originally Posted by billybek

Mine started stretching right before it broke. Had done several adjustments and it wouldn't stay adjusted very long.
It broke when I was about 50 miles out of town.

did it break in one of the end crimps as walt suggests? I agree that the cable portion would never lets go, but I also agree with Gordo's example that a cable will stretch coming more tightly wound as it ages under tension..

[Flat6pac]

The adjustment at the transmission always seems to be at the end of allowable adjustment.
What I have found is, at the front clevis, the factory places a locknut to the clevis.
In the clevis there is at least 17 threads then locked.
Remove the lock nut, you're solid locked forward and solid to the trans so the locknut is superfluous.
If you're not getting the setting on the beldin adjustment you can un hook the cable and take more turns into the clevis from the trans area.
Another thing on adjustment, make sure the beldin is seated tight to the fire wall extension.
Bruce

[Gordo2]

Thanks for the feedback folks,

I tried to take a few photos showing how the windings have separated - but couldn't seem to get as clear of a shot as I did for the one that shows how the windings should look. Meanwhile, it's visibly not right - the cable windings are visibly separated.

Additionally, the same stretched section is ever so slightly bulged.

For Walt - based on the discoloration / rust coming from my cable, I assume the clear outer casing has been compromised (no longer sealing the cable wires), which allowed the exposed the cable to be subject to moisture and it rusted - which contributed to the separation of the windings and stretch. It's similarly rusty and stretched near the crimped cable end that attaches to the clutch arm.

For Flat6Pac - I considered adjusting how far the cable end was threaded into the clevis / pedal attachment, and agree - I could have adjusted at that point in order to provide additional adjustment / threads at the transmission. I considered doing this, however it seemed that the cable had stretched beyond what was previously OK to adjust, which prompted me to buy a new cable.

Thanks again,


Gordo

[Gordo2]

New clutch cable arrived - but I found that cable stretch really wasn't the problem.

Upon further inspection, I've found that the clutch pedal shaft roll pin was in fact broken.

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Today I removed the pedal assembly - not too difficult:





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And removed the broken roll pin - which was as much a PITA as others have described:

The original roll pin is rather unique - it's truly rolled metal, unlike most roll pins that have a single slit and slight overlap of the metal.


Clutch Pedal Shaft Roll Pin Removal
- I tried my air hammer with a pointed tip attachment (per John W's recommendations) but it just flared / smashed the roll pin on the exterior surface of the clutch pedal.

- I also tried a few different sized punches, but they didn't budge the pin (however the punch did knock out part of the pin that was broken off).

- I succeeded by drilling through the pin, and then used the punch to back out the remains of the pin.

In all removal of the pedal assembly and the painful pin took ~ 2hrs (to include removing the driver's seat to provide more room to work).

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Clutch Pedal Shaft - Worn out Roll Pin Hole

My pedal assembly had been previously rebuilt; when I bought the car, the pedal assembly already had brass bushings.

Meanwhile, it appears that the hole in the clutch pedal shaft was either wallowed out during the previous rebuild, or the broken pin enlarged the hole:



The hole in the clutch pedal shaft was larger than the hole in the clutch pedal attachment.


I also noticed that the clutch pedal shaft was missing a spacer:



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New clutch pedal shaft and associated parts are on order.

Will follow up when the parts come in and I can get back to the project.

Gordo

[yelcab1]

new shaft is a good call.

[billybek]

Originally Posted by juanbenae

did it break in one of the end crimps as walt suggests? I agree that the cable portion would never lets go, but I also agree with Gordo's example that a cable will stretch coming more tightly wound as it ages under tension..

Was strange that this cable broke about 7" up in the cable housing.
Ends looked perfect.
Sorry for the late reply, I had lost track of this thread.

[shoooo32]

I just had the exact same experience as you, Gordo. I thought the cable had stretched and kept adjusting and adjusting, each time getting worse not better (even with the new cable). Luckily, I bought a pedal rebuild kit from our host prior to this so I had the pin and new bushings on hand.

I can see why people put this off. It's a hassle to get it out of the car and an even bigger pain to drive the old pin out. I had a second set of hands to help and even then, one of us almost lost a thumb.

[Gordo2]

Parts came in this week - but between the East Coast heat / humidity and my available time to work on it, the project has been delayed.

The pedal refresh is well documented in multiple threads, so I won't repeat. Meanwhile here's my observations:

- Removal of clutch pedal roll pin is challenging. Meanwhile - removal requires patience vice technical skills or special tools... Installation of the new roll pin was pretty straight forward - I put it in the freezer for a bit, and tapped it into place with a brass drift and hammer.

- Re-installing the clutch helper spring on the pedal assembly can be very easy if you do it before you install the assembly in the footwell. Meanwhile if you install the spring on the workbench, it makes installation of the pedal assembly a bit more difficult (the spring gets in the way of the bolt that attaches / goes through the pedal brace). Choose your poison.

- The method of expanding the clutch spring by inserting quarters between the coils works quite well. If you pre-install the spring on the workbench, you can even install it and rotate the pedal and bracket into place, without expanding the spring (difficult to describe, but do-able).

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Post Rebuild, Driving Observations

Since I was into this job to repair a broken clutch pedal roll pin, my expectation was nothing more than going from broken to working - with no anticipation that I would find any noticeable improvement to the pedal feel.

Meanwhile - I replaced the clutch cable, pulled/cleaned and re-greased the pedal assembly (existing brass bushings), replaced a missing pedal assembly spacer and spent plenty of time adjusting the clutch pedal to spec.

After all this, I'm happy to report that it works... and feels better than ever; as such I recommend pedal assembly refresh be included if you are rebuilding a trans or replacing the clutch

I think most of the improved feel is due to the fact that with the new cable - I can actually adjust the clutch pedal and cable to spec.

Here's a final photo showing the pedal assembly installed with the spacer that maintains the space between the clutch arm and the throttle arm:



Thanks for the feedback,

Gordo