Clutch adjustment issues

[Gretz]

Getting pretty close to the end of my rope here so I'm hoping one of you has some good input. I think I've read just about every thread on here about clutch issues and adjustment.

Several months ago, while the engine was out, I noticed a small crack on the clutch release fork inside the bellhousing so I replaced it before the engine went back in. I have verified it appears to be oriented correctly. Lubed everything. While reinstalling the engine I also noticed the large clutch release arm had some wear, so I ordered a new one but in the meantime I reinstalled the old worn one. Adjusted the clutch to spec, although I never checked/adjusted the engagement range.

Fast forward a couple months of the car driving just fine. The clutch then began to feel like it was slipping a bit when engaging after a stop. Clutch was installed by previous owner about 20k miles ago, and I'm not terrible at driving a manual transmission. Then the pedal began feeling like it was sticking a bit when pressed all the way down. I figured, no big deal, I'll install the new clutch release arm and check the adjustment on everything.

I installed the new arm, including new needle bearings. Checked and lubricated everything. The stickiness at fully pressed did not improve. I then rebuilt the pedal cluster and decided I might as well replace the omega spring and assist spring on the gearbox too. I also installed a new clutch cable with a new clevis fork and pin. Clevis fork was installed at ~19mm. The old cable was about 10 years old. No joy, same stickiness still exists. I also went ahead and replaced my old original floorboard with a Rennline one since the old one was close to total disintegration.

Another point of reference: I can't get the engagement range to the spec of 25mm +/- 0.5mm. With the stop at the floorboard pushed all the way forward, I can get about 23.8mm of range.

When pressing the pedal, it mostly feels fine until it's pressed all the way down and feels like the cable may be binding in some way. Sounds like it too (watch the videos). I have checked the tunnel with my scope and don't see the cable hung up on or touching anything. I almost feel like this is the behavior I'd expect if the pedal were pressed too far, but I am still below the 25mm engagement range spec.

Here is my cable adjustment procedure:
1. Remove cable from large release arm.
2. set gap between bolt on small arm and the big arm to 1.2mm
3. Reattach cable and tighten nut on clutch cable to 1.0mm to preload

So to summarize, I have:

-Rebuilt pedal cluster including bushings, springs, etc
-Replaced clutch cable, clevis fork, clevis pin, release fork, large release arm and needle bearings, omega spring, small assist spring, floorboard, clutch pedal stop on floorboard
-Adjusted clutch one million times

I am wondering if perhaps lubing the new cable ("German" OE not Porsche, but had 911 OEM style sticker and purchased from Pelican) might help. Or adjusting the clevis fork? I'd really appreciate some enlightenment here, folks.

Here are some videos and pics:

VIDEO: Clutch cable etc on underside of gearbox:
https://www.dropbox.com/scl/fi/406xv0pn4svajx3nbhh3o/Gearbox.mov?rlkey=z340f3yxz54539fvm1uhtuunf&st=arqan3h9&dl=0

VIDEO: Pedal cluster:
https://www.dropbox.com/scl/fi/1515umfe253zky6mr66uq/Pedals.mov?rlkey=g0t1vbfxz4v72cnwilwfr3b39&st=sav3saay&dl=0

[porschedude996]

That is odd. I hear the click at the pedal, but the video of the eng/trans sounds like there is something going on inside the clutch area. Do you have the correct pressure plate and bearing? Maybe the bearing is being pushed too far? Are you dure you got the fork positioned on the bearing properly? Just throwing so stuff out.

[Gretz]

Yes, the pressure plate and bearing were replaced about 20k miles ago by the PO. The fork looks fine to me. I think it’s possible I’m pushing it too far out with the pedal, but it seems like that would be more than the 25mm engagement range and I can’t even get that.

[porschedude996]

Is the cable catching on the inside of the tube? Underneath the boot.

[garment]

I know that sound.

The jam nut at the clutch arm, under the trans, is not adjusted properly. The sound you hear at the pedal cluster is the end of clutch pedal hitting the floor of the car.

When it happed to me, it took me longer to jack up the car than to diagnose and fix. Tighten the jam nut and adjust clutch cable length properly and it will go away. Good luck.

[Gretz]

I’m using the standard procedure of setting the gap with the cable detached to 1.2 MM and then attaching the cable and adjusting the gap to 1.0 MM. Do you have a better or different procedure?

Also, there are two different sounds: the pedal is definitely hitting the forward pedal stop, but there’s also a sound from underneath the car that sounds like the cable is binding on something.

[garment]

But is the jam nut tightened at the clutch arm?

Originally Posted by Gretz

I’m using the standard procedure of setting the gap with the cable detached to 1.2 MM and then attaching the cable and adjusting the gap to 1.0 MM. Do you have a better or different procedure?

[Gretz]

You mean the one that is securing the adjustment screw? Yes, it’s tight. I measured/set the gap at 1.2mm, tightened the jam nut on the adjustment screw, then used the 15mm nut on the cable to close the gap to 1.0mm to preload the cable.

EDIT: I know that the clevis fork is usually set between 17-22mm. Can someone explain what the symptoms of an improperly set clevis would be? (Mine is set at 19mm)

[ant7]

Sounds to me like the pedal, or the part that the cable fixes to is snagging on something!
I don't think its anything to do with the gearbox end, concentrate your efforts at looking at the pedal end.
Hope this helps.
Ant.

[Gretz]

EDIT: never mind. For a short time, I thought that increasing the cable tension solved my problem, but it did not.

[pmax]

Originally Posted by Gretz

...
Fast forward a couple months of the car driving just fine. The clutch then began to feel like it was slipping a bit when engaging after a stop
...

I would check the fork/TOB again. Snake a borescope to the "viewing portal" on the top of the tranny.

[Gretz]

Update: My memory sucks. When the engine was out, I replaced the guide tube due to wear, but the clutch fork in the bellhousing did not have cracks and was not replaced. According to invoices from the PO, the clutch release fork was replaced along with a clutch kit (incl pressure plate, TOB, flywheel bolts) under 20k miles ago. Fork was removed by me to clean the shaft and install new seals, add lube, and a new roll pin was used to reinstall the fork.

I'll try to get in there today and get a video of the action in the bellhousing to share.

[David Inc.]

Binding at the pedal? Maybe the clevis assembly is catching on something?

I remember someone else having an issue with a sticky throttle that ended up being the throttle linkage being on the wrong side of the clutch clevis--maybe you have a similar issue?

Edit: Well that wouldn't have caused the progressive worsening from before the cable change. Hmm. Yeah, as others I'd say check the fork and TOB with a boroscope, maybe the pressure plate as well.