Clutch wont disengage

MrScott · 05:54 PM

It started with clutch chatter about three days ago, this morning I couldn't shift into gear without grinding. I spent the last hour adjusting the clutch cable per the bentley manual. It took me a while because I would adjust the gap just right, go for a test drive, worked perfect then some grinding, more grinding, won't shift -- all in the span of about a minute or two. Check the gap again, now it's too large, tighten, repeat. Now the cable's at the end of it's adjustment... Luckily I have a spare/new cable on hand.

So my question: are these symptoms of a worn cable or will I go through the trouble of replacing it to find I'm back where I started?

Only way I can think for the cable to fail with these symptoms is if the strands are snapping moving it further out of adjustment.

I limped to the corner store in 2nd to stock up on beer and smokes. If you all tell me changing the cable will do it I'll skimp on sleep tonight and get it done.

tevake · 09-01-2010, 06:35 PM

That does sound like the cable is breaking strand by strand and stretching as it does.
I have read here that is fairly common type of failure.
You ought to give the peddle cluster a good look over while you are at it.
Let us know how it works out.

Good luck Richard

pete3799 · pete3799's Garage

Could be the cable,could also be the clutch fork is breaking (cracking)
I'd put the new cable on and hope that does it. If not you will have to drop the motor/tranny
and inspect the release arm on the throw out bearing. Hope the cable does it for you.

moneymanager · 09-01-2010, 07:16 PM

It's the cable, or the roll pin that holds the clutch pedal to the cluster shaft, or the piece at the other end of the pedal cluster which actually "pulls" the cable when you pull on the shaft. And if it isn't one of these, it's the clutch fork. All of these can display the symptoms you have, including the roll pin which broke on my car, would hold for a week or so, then slip, then hold for a bit.

MrScott · 09-01-2010, 07:31 PM

Thanks guys. Pedal cluster, pins, etc. Look solid. I'm about the remove the cable and thread the new one in. I get the feeling it won't be as easy as those two short sentences in bentley suggest.

moneymanager · 09-01-2010, 07:36 PM

Note that the cluster pin could seem solid as a rock and still be broken. But I'd start with the cable. If there's nothing wrong with the cable when it comes out, expect to look further.

MrScott · 09-01-2010, 08:05 PM

Cable's out. The sheath on the transmission end was gouged (metal looked fine) and it's slightly longer than the new one but other than that it looks fine. What should I be looking for?

MrScott · 10:09 PM

Well it's not the cable. New cables in, no difference. And it could be my inexperience, but I had trouble getting the clearance for the cable adjustment consistent with the cable attached. Also, my clutch pedal feels a little too easy to press. Ideas? Next step?

Edit: I forgot to mention. I found the rubber stopper for the clutch pedal lying on the floor near the pedal. I'm thinking that extra bit of travel might have been enough to overextend something...

pcar9119 · 09-02-2010, 12:41 AM

When my car was doing that, it was my clutch disc and a clutch fork. When the fork broke, I replaced the disc also, so not exactly sure which one was causing the problem, but my guess is the disc, but check the fork for any cracks. Also, before you do that, look into the window in the transmission, see if you can see clutch material. Thats what I saw when I started mine. If that fork is flexing, it could do the same thing, you wouldn't beable to get the adjustment right. Good luck, hope I was some help!

brentrussell · brentrussell's Garage

Don't know if its similar but I had this issue with a Mitsubishi EVO, what actually happened was the pressure plate came loose, I would adjust it up good then drive and it would have walked around to a different position. Have you had the clutch/flywheel apart recently?

moneymanager · 09-02-2010, 06:12 AM

Again, check the roll pin on the clutch pedal at the cluster before you go any further. Drive it out with a drift pin and look at it. It's a whole lot easier to replace than the clutch fork.

MrScott · 09-02-2010, 07:43 AM

No I haven't had the clutch apart recently. Taking a look in the window sounds easy enough.

moneymanager,
I didn't mean to dismiss your suggestion, just wasn't sure how to proceed. Now that I've seen a picture of the roll pin (below for reference) I get it.

Thanks everyone for your help.

From Pelican Technical Article: Pedal Cluster Rebuild

moneymanager · 09-02-2010, 07:48 AM

You may need to drill it out as shown in your excellent pic but sometimes a big nail with a flat end or a real drift punch will get it without even removing the cluster. BTW a 6mm screw can be substituted for the pin in a pinch...it will be loose but it will work.
You have one of those problems where it makes great sense to check all of the possible failure points in order, from easiest to hardest. I'm probably not the only person here to pull the motor looking for a broken clutch fork, only to find that it was the roll pin in the cluster all along! Keep looking.

MrScott · 09-02-2010, 08:13 AM

So it occurred to me that, since removing the pin may be tough (not sure if the cluster has to come out) an easy way to rule out the cluster would be to measure the cable travel at the transmission end which bentley lists as 25 +/- .5mm. If it's less than that it's got to be the cluster. Does that make sense?

moneymanager · 09-02-2010, 08:32 AM

Yes but I don't think it will get you there. If the pin is broken and jammed in place it would move the cable perfectly. And it would again measure perfectly ten minutes later after your clutch pedal had slipped 5° and was non-functional.
You can get this out, at least I can on my 74, without pulling the cluster. But if you have to pull the cluster it's not that awful. And, again, we're trying not to pull the engine here.

pete3799 · pete3799's Garage

If the roll pin is sheared you should be able to see the pedal move indepedantly from the
center shaft. Clean the area good and watch it as you push on the pedal.

moneymanager · 09-02-2010, 08:40 AM

Pete, you're right. you should be able to see it. But the last time it happened to me I couldn't... the pin broke in three places and jammed in place somehow. The clutch would work for 2-3 hours, appeared perfectly attached, then slip 10° making engagement of first or reverse impossible.

MrScott · 09-02-2010, 11:14 AM

Looks like good news. I did a quick check of the position of the clutch positioning lever relative to the transmission. After fully depressing the clutch pedal the gap between release lever and positioning lever increases, but the position of the positioning lever relative to the transmission doesn't change, so the change must be coming from the pedal end. I should have the pedal cluster out by tonight. Hope to see something that confirms my test.

cudabnu · cudabnu's Garage

I had an issue with mine, Found out where the clutch cable attaches to the pedal assembly, there was now small brass bushing and the clevis pin was also worn down 1/2 way. I could not tell just by looking at it, only after completely remove the clevis pin did I see why I was having the problem. all new parts put back in and it works great!

MrScott · 10:33 PM

Slow progress. I wasn't able to remove the clutch pedal pin with the assembly in place.
The pedal cluster is has one bolt still holding it in (17mm) which I can't seem to remove (pic below.)

I'm using an open end wrench and pulling until the assembly starts to flex -- before I break something, is there a trick to removing this bolt? Doused it in PB Blaster to let it sit overnight.