Ahh, no wonder my clutch-pedal throw is a mile long...

Mike Thomas · 10-18-2008, 09:36 AM

I recently had my clutch cable and cross shaft replaced (cable frayed, and cross shaft nearly eaten through due to the bushing dying who knows how many miles ago). When I got the car back, operating the clutch was much smoother, but now that it was smoother, the heavy return spring and long travel before engagement made it difficult to release the clutch smoothly without undue concentration.

I had resigned myself to just getting used to this, when it occurred to me that I might try to adjust the rubber pedal stop to allow less travel (within specs). So, I pulled the carpets out and back to have a look, and lo and behold, there is no rubber stop. A-HA!!

One is on order from our host (naturally, with a lot of other bits-n-bobs).

dshepp806 · dshepp806's Garage

Who did you work? mmmm?

Best,

Doyle

Mike Thomas · 10-18-2008, 10:22 AM

Quote:

Originally Posted by dshepp806

Who did you work? mmmm?

Best,

Doyle

Yes, I my first thought was to blame my mechanic. But seems to me, the car has always had a very long clutch throw, it just used to be long and rough. Now it's long and smooth. Could be he forgot to replace the stop, or didn't notice it was missing. It's easier for me to just order the new $2.50 part than convince him its his fault and make him get me the replacement.

Actually, I'm just happy I found the problem.

surflvr911sc · surflvr911sc's Garage

Those are often missing, and I wouldn't count on it making much of a difference in the feel of your clutch throw.

Edit: Have you made sure that the clutch is properly adjusted? How old is your clutch?

robert walsh · 10-18-2008, 10:50 AM

I agree, put one in last month and thougth it would make a "big" difference, it made me feel better but thats about it. Get the clutch adjusted correctly to spec, by the looks of your pic, the floor board adjustment seems to be almost if not all the way in the down postion, meaning your pedal travel is at it's smallest throw, I think your cable has to be adjusted at the helper spring under the tranny, and also the clevis pin has to adjusted on your new cable at the pedal area. It's ashame if that's the case as it should have been done durring installation. Not a major but it is truely one of those pita, very crampt working area.

dshepp806 · dshepp806's Garage

yes , it should have been noticed and addressed.. Hopefully it works out for you.

Best,

Doyle

john walker's workshop · 10-18-2008, 02:48 PM

i take the whole thing off on my cars. my legs are long and i like to put the pedal all the way to the floor and have the engagement point about 3" off the floor, so i can pivot my foot off my heel. it's not like you really need that stop.

Mike Thomas · 10-18-2008, 02:53 PM

Sigh.

I've never driven a car that takes so much concentration to get started. I guess now the car will be more "complete", but no easier to get started from a stop. I will eventually get to adjusting the clutch, but I kind of assume that would be part of installing a new clutch cable and cross shaft.

Thanks for the responses everyone, even though they bum me out.

john walker's workshop · 03:32 PM

it only takes a few minutes to adjust the cable to get your engagement point more comfortable. on a '82, you would adjust the 2 nuts on the cable sheath at the trans bracket to change the engagement point. moving the sheath to the rear lowers the pedal. this is done after you adjust a very small amount of clearance between the long and short arms below the bellhousing, via the bolt and locknut on the long arm.

Mike Thomas · 10-18-2008, 05:25 PM

Quote:

Originally Posted by john walker's workshop

it only takes a few minutes to adjust the cable to get your engagement point more comfortable. on a '82, you would adjust the 2 nuts on the cable sheath at the trans bracket to change the engagement point. moving the sheath to the rear lowers the pedal. this is done after you adjust a very small amount of clearance between the long and short arms below the bellhousing, via the bolt and locknut on the long arm.

Thanks John, for your instructions!

It would only take you a few minutes to make the adjustment

. Then there's me. I've read the adjustment procedure over and over. It does seem pretty straightforward. But I'm not even a weekend warrior at cars (bicycles I can do, but I can throw one of those up on a workstand in about two seconds) and executing this procedure on my car comes ony after I research and buy the right jack and jack stands and re-read the procedure for getting the car jacked up appropriately for this procedure, and then worry that I'll do something stupid and hurt the car or myself, and then finally get it up and try the adjustment, and then bring the car back down to test it and not like that adjustment and jack it back up and .... It's a beating just thinking about it.

Then there's my prior-911-owning coworker, who does autocross for fun, and who's literally owned and modified hundreds of cars, who tells me "it doesn't matter what you do those cars have funky clutches -- it always felt like an on/off switch to me". And when I describe the engagement right when the pedal starts pushing back hard, he just nods knowingly and says "yeah, sounds familiar". This guy does all his own work on all his cars and trucks. Kind of makes it hard for me to get excited about the experience of working on this particular issue.

I did just get the car back from a clutch service, and it seems like the mechanic (the owner of a very well regarded shop in Denver) would have done this adjustment as part of that service.

If anyone's still reading, I'll say that perhaps I should have written my original post more carefully: my clutch has a long throw and doesn't seem to engage until the pedal is something like halfway off the floor. It's a long way up (it feels that way, anyway), and then seems to start engaging right about when the springs start ramping up, and thus it's hard to control the engagement smoothly. It's almost like doing a negative leg press with a variable weight. I feel as though if the clutch would start engaging sooner (relative to the whatever "bottom" there is), then I'd have less miles of travel before it engages, and thus less variance in pressure that I have to provide, and could therefore kind of get going more quickly and smoothly. I'd hoped the pedal stop would provide some of that relief by reducing the bottom of the travel a bit.

I love everything about the car except for this one thing, and I'm getting kind of used to it, but it still eats at me a bit.

Thanks to all of you for listening to my whining and offering your suggestions and help! I love this board.

robert walsh · 10-18-2008, 06:23 PM

You and your freind are correct, it is different feel with the cable actuated set up, but trust me, the adjustments are quite simple and once you get it into spec you'll find the travel will not be nearly as long, make sure the bowden tube is facing up into the tunnel rigth after your adjustment nuts at the helper spring area, and also make sure the cable is not touching the throttle linkage at that point (rear underneath) as that will play havoc with proper release. There is an article in the tech info center tab above linking you to the simple adjustment procedure, it took me awhile but it's 100% better now with very little problem associated with clutch chatter durring release that I was experiencing.

john walker's workshop · 10-18-2008, 09:52 PM

just take it back to the guy who did the clutch and have him redo the adjustment until you like it. everybody likes it a little different.

Mike Thomas · 04:14 PM

Well, since I've already ordered the rubber stop, naturally I'll go ahead and install it. I have lower expectations now, but that's OK. A fellow semi-local Pelican reminded me that he'd be willing to provide tools and experience for an adjustment, so I may go that way. Failing that, I can live with the car/clutch as is until I get it back into the shop for the next round of elective surgery in the spring (suspension freshening, alignment, corner balance, etc).

Thanks all, for your input.

PS - Little problems like clutch adjustments become less important on a beautiful fall day in Denver. It was gorgeous today, so I got the car out to run some errands and do a little photography.

rootmatt · 10-20-2008, 06:03 AM

Quote:

Originally Posted by Mike Thomas

Then there's my prior-911-owning coworker . . . tells me "it doesn't matter what you do those cars have funky clutches -- it always felt like an on/off switch to me". And when I describe the engagement right when the pedal starts pushing back hard, he just nods knowingly and says "yeah, sounds familiar".

. . . seems to start engaging right about when the springs start ramping up, and thus it's hard to control the engagement smoothly.

Yep. That's how mine felt before I changed the cable, greased the throw-out mechanism and adjusted as per instructions. Feels great now. The weight on the pedal stays roughly constant during clutch engagement so I can take off smoothly.

FWIW, my theory is that the adjustment of the clearance between the two levers on the cross shaft affects the synchronization of the helper spring during the take-up process. The helper spring's assistance varies throughout the range of the pedal's travel. At one end of the range, the helper spring rocks over-centre before the clutch release lever relaxes onto its stop. Clearly by then it is no longer providing any help. I reckon that, before adjustment when the clearance on mine was zero, the helper spring was ceasing to help just at the critical moment of engagement.

Whether or not my theory has merit, correct adjustment achieved, for me, a clutch that no longer pushes back during engagement. There is hope.

Mike Thomas · 10-20-2008, 07:37 AM

Quote:

Originally Posted by rootmatt

Yep. That's how mine felt before I changed the cable, greased the throw-out mechanism and adjusted as per instructions. Feels great now. The weight on the pedal stays roughly constant during clutch engagement so I can take off smoothly.

... clip ...

Whether or not my theory has merit, correct adjustment achieved, for me, a clutch that no longer pushes back during engagement. There is hope.

Thanks rootmat, having someone second my exact experience before the adjustment, and better behavior after, gives me assurance that the adjustment is worth attempting. Too bad the guy that replaced my clutch cable didn't adjust (as far as we know) to recommended specs.

Mike Thomas · 08:54 PM

Success!

I got the rubber pedal stop yesterday, and installed it tonight. What a learning process. Getting the floorboard out was like solving one of those bent metal puzzles. Next time I'll start out by pulling the rubber off the clutch and brake pedals and removing the gas pedal. And boy, is getting the accelerator linkage snapped back into the gas pedal fun!

It naturally couldn't be a straightforward fix: if you look at the original photo, you can see that the "grippers" for the stop were bent down due to the pedal arm striking them while the rubber was missing. So, I had to carefully pry them back into place with a thin flat screwdriver. I had to remove the pedal stop assembly from the floorboard in order to do this. The result isn't perfect, but it's very close, and the rubber slid in with some coaxing and seems pretty solidly in place. When I replaced the stop assembly, I adjusted it a little higher on the floorboard to compensate a bit for the extra material that's there now.

The verdict? The clutch is now like butter. The throw is what I'd expect just sitting down in any random manual-shift car and depressing the clutch. Basically, it is what I dreamed of when I started this thread. It's is much more manageable and predictable now and I can engage it with very little concentration, due to a shorter throw and therefore less "wait for it ... wait for it" engagement, and less variance in the amount of resistance the pedal provides to the foot. This improvement is what I'd originally theorized WRT replacing the rubber pedal stop.

Of course, there was the anxious moment of truth, where I started the car in neutral, depressed the clutch and slid it slowly into first. Voila!, no grinding or resistance, just snicked right into first. Went through all the gears with the clutch pedal down, and all went well. Backed it up a bit, and then forward. Fine.

Though the top was off, and it was about 30 degrees, I took her out for a spin and had no issues. I could even engage the clutch during turns while maintaining control. I figure I'll also be able to engage it more smoothly over rough pavement, which was always a challenge before.

Now I suppose everyone is going to tell me how I'm going to screw up my clutch because it might not be totally disengaging now due to the shorter throw?

javadog · 10-24-2008, 03:55 AM

You know, there is a procedure for adjusting the clutch. It's pretty simple really, so why not do it? In short, with the cable disconnected at the rear, adjust the gap between the levers to 1.2mm. Attached the cable and adjust the nuts until the gap reduces to 1.0mm. Lock it all into place. Have someone get in the car and depress the clutch pedal. Measure the travel of the cable and adjust the cable stop in the front until you get around 25mm total travel. (You might want to double check the 25mm number; I'm going off of memory here.)

Obviously, you want the clutch to release all of the way. You also don't want too much travel, as it puts a strain on the clutch cable. This might have contributed to your earlier cable fraying.

JR

Mike Thomas · 10-26-2008, 11:10 AM

OK, a local Pelican helped me do the adjustment. Actually he performed the adjustment. I think I handed him a wrench, and maybe actuated the pedal a few times, and tried to stay out of the way.

All is within proper tolerances now, and as everyone has said -- it's a night and day difference, with or without the rubber stop (which fell out when I was doing the final adjustments there to get the overall travel right) . The clutch pedal travel is not nearly as far, and starts engaging sooner. It's just like his car now (which I drove before we did the adjustment). And, since the clutch cable had already been replaced, the pedal action is super-light. I have to admit that I'm not sure I trust my shop as much now, given that an adjustment procedure should naturally follow a cable replacement (wouldn't you think?). I don't swap a cable on a bicycle without adjusting the brakes or derailleurs.

Anyway, all's well that ends well, and from now on I'll just shut up and listen

.

javadog · 10-26-2008, 07:06 PM

If your shop replaced the cable and didn't properly adjust it, or notice the rubber bumper was missing from the clutch stop, I'd suggest that you never go there again. That's really bad workmanship.

JR

Mike Thomas · 10-26-2008, 07:52 PM

Quote:

Originally Posted by javadog

If your shop replaced the cable and didn't properly adjust it, or notice the rubber bumper was missing from the clutch stop, I'd suggest that you never go there again. That's really bad workmanship.

JR

You know, I'd have to agree. Sad thing is, it's a well-regarded shop, and I like the guys that run it. They have been very conservative with recommending repairs (but perhaps way too conservative when it comes to addressing details?).

Thanks again all for the help...