Clutch cable adjustment woes

[MattAlpha]

I just finished installing a new clutch cable and now my clutch pedal will not return to its proper height. I've adjusted the cable three different times, but I can't seem to get the pedal to return back to its normal height. I only have about an inch and a half of pedal throw. Everything is working I tested the function of the clutch with the engine running, but the short throw still has me really confused.

Does anyone have any suggestions? I'm very frustrated and calling it a night for now. I'll go at it again in the morning.

-Matt

[Eagledriver]

1.5 inches of clutch travel should not be enough to disengage the clutch. Did you compare the length of the two cables? Sounds like you just need to shorten the cable with the adjustment on the clutch fork at the tranny.

-Andy

[GH85Carrera]

That sounds strange to only have 1.5 inches of pedal movement. It looks like you have extensive mods to your Porsche. What transmission do you have?

[john walker's workshop]

first adjust a very small amount of clearance between the two arms by adjusting the bolt. next adjust the sheath forward by adjusting the two nuts on the sheath rearward. that second adjustment will raise the pedal. it probably needs to go forward more.

[MattAlpha]

Thanks guys.

I've got the original '78 915 transmission in the car still.

John I've got the sleath adjusted almost all the way toward the rear.

When I get a chance to work on it today, if things don't work out well, I'll post a few pictures of the cable adjustment and the pedal.

-Matt

[AngM018]

Did you put a block of wood behind the pedal to prop it up when you adjusted it? That and you will have to do another adjustment after you drive the car (as per factory manual)

[OldTee]

There is something wrong with this adjustment. It worked. Note the adjusting nut is all the way out (or in). The txmn is now out of the car so I plan to readjust the whole thing next time. This was done by the POs professional mechanic. Note it is a new cable.

[MattAlpha]

AngM018,
I did prop the pedal up with three blocks of wood to hold the pedal at the highest position possible, but soon as I removed the blocks and pushed the clutch pedal in, it only will return to about half the height that it should. Thank you for the note about re-adjusting once I've driven it though, I did not know about that.

Old Tee,
Thanks for the picture. My set-up is similiar, but the adjustment stop bolt is not all the way out. I'm going to try to follow John's advice and hopefully that will fix my problem.

-Matt

[john walker's workshop]

the front end of the cable needs to protrude into the clevis fork about 8mm or you can run out of adjustment at the rear. to much protrusion and the cable end can contact the pedal release arm when the pedal is pushed down.

[Jadams1]

John W., Thanks! You graciously give solid advice to all of us on a daily basis. I always learn something from your posts.

Sincerely,

John Adams
Coventry, RI

[MattAlpha]

John,
I went over things again and I'm still having the same problem. I originally threaded about 20mm of front of the cable into the clevis fork because the Bentley manual states that you need to thread between 17 to 22mm, so I went about middle of the road. Is the Bentley manual wrong and indeed you should thread 8mm into the clevis fork? If that is the case then, that is one of my problems.

Here is a picture of where I was at the end of last night:


The other problem that I've identifed is that when I do the first adjustment (with the cable disconnected from the clutch release lever), I set the gap between the clutch positioning lever and the stop bolt to 1.2mm. Once I re-attach the cable, I can not adjust the two nuts on the sheath to obtain the 1.0mm gap between the clutch positioning lever and the stop bolt. So if I need to re-adjust the front of the clutch cable into the clevis fork, that may fix the problem. Though I was reading in the Bentley manual that another option that might solve my problem is the clutch release lever has become joined to the clutch release cross shaft due to corrosion. So I started to try and remove it to check for corrosion and wear, and it is indeed stuck to the clutch release cross shaft. I've removed the clutch cable, positioning lever spring, the circlip (at the bottom of the shaft) and the clutch positioning lever. I've heated the clutch release lever around the shaft once and I've PB blasted it. I'm waiting for it to sink in right now.
Current (not in great focus) picture:


It appears that the entire clutch arm mechanism (including the auxiliary return spring) will remove as one unit. Can someone who has done it verify that for me? Any advice is greatly appreciated.

Thanks,
Matt

[Inniswhe]

Yes it it should all come off as a unit. I took mine off this morning . After the small arm was taken off I wiggled the large arm back and forth to get it too loosen up and slide off the shaft. What year is your car. I believe some older years might have had a lock pin.


Ross

[BrokeMyCar]

For a point of reference, my 82SC had a lock pin. See: Throw-Out Arm Removal: Leverage?

I had similar symptoms as you regarding the pedal height, ended up that the omega-spring was in the wrong position (and not working right; I think I broke free the rust with all the liquid wrench treatment). Its summarized in the last post of:

Clutch Cable Investigation

Good luck!

Babak

[MattAlpha]

Ross,

The car is originally a '78 RoW Targa SC. It still has the original 915 in it. I haven't seen a pin. Did you wiggle the large arm in the vertical aixs (up and down) to loosen? That is what is seems like you're saying, but I just want to make sure.

Thanks,
Matt

[john walker's workshop]

the 8mm i'm talking about is not just 8mm worth of thread screwed into the clevis, but the cable threaded into the clevis completely until it comes out into the fork end of the clevis 8mm.

[MattAlpha]

John,

Thank you for clarifying, once I get back out there (after I get my kids to sleep) I'll check that and adjust as necessary.

Do you have any advice on removing the clutch release lever, or am I proceeding down the right path?

Thanks,
Matt

[scarceller]

If I recall correctly, last time I adjusted my cable in my 84 Carrera with a 915 I found it very easy to get the adjustment set properly at the trany end of the cable. But the pedal was not coming all the way up and I simply adjusted the cable (made it shorter) right at the other end at the pedal cluster.

Basic idea is adjust the rear (trany end per the book) then move the pedal travel up or down by the adjustment at the fork at the front of the cable. It's a pain in the ASS because that end of the cable near the pedal cluster is in the tunnel. You may find it easier to disconnect the cable at the trany and pull it forward at the front tighten (screw in) the fork to move the pedal higher then re-assemble the front then the rear.

Good luck.

[Inniswhe]

Mattalpha,

I wiggled the lever forward and back in the plane it is supposed to rotate . If it does that you know it is not frozen to the shaft. I placed a large screwdriver under one edge and pryed while I worked the lever . It would not budge until I started wiggling the lever.

If I were you I would look close for a pin though to be sure. Some SC's apparently had them.

Spray some PB and let it sit as well, this might help.

Ross

[MattAlpha]

I just got back in from my thrid attempt today and I'm calling it a night.

I verified that I do not have the lock pin (thank you Babak for your link), for which I'm grateful, but the clutch release lever is still stuck on the shaft. I heated it another time and I used Ross's method of wiggling the release arm forward and back as I tried to pry the lever downward. So I soaked the lever from the bottom again and I'll let it soak/seep tonight.

Question: I'm only PB Blasting it at the bottom of the lever (where the shaft protrudes) because I'm weary of getting PB blaster on the higher end of that shaft and PB getting into the Tranny by some odd mechanism. Am I thinking about this correctly or am I wasting time and I should be spraying each end?

John: I looked at the clevis fork again (after disconnecting it) and I had about 9mm protruding , so I adjusted it down to 8mm as you suggested. When I hook everything back up (hopefully tomorrow) hopefully everything will be good.

Thank you again guys,
Matt

[scarceller]

Our host has a great article on clutch cable replacement and adjustment. I used this article to adjust my cable. May be worth a look.

http://www.pelicanparts.com/techarticles/911_clutch_cable/911_clutch_cable.htm