Clutch...or cable & helper spring?

[jamesiii]

Hi all,

I've been researching the archives all day and I can't find anything definitive on determining whether I have a clutch problem, a cable & helper spring problem, or a combination of both.

What are the tell-tale signs of each? I adjusted the linkage this weekend and had little to no effect on 1st and reverse grinding almost every time (unless the car is REALLY warm). I found an initial throw of 13mm (instead of the 25+/-.5 that Wayne's book recommends, adjusted the clevis (?) as much as possible but I'm still only up to 20mm. Also, the clutch pedal won't return all of the way. It seems like this is symptomatic of a bad helper spring, but why can't I achieve the 25mm of throw?

Any ideas would be appreciated...I'm wondering if I should just start with replacing the cable/ helper spring and all associated parts and see if it helps...or should I bite the bullet and do the entire replacement "kit."

Thanks in advance!
Jim

[yelcab1]

I have never been able to get 25mm on my clutch. Not even close. I would suggest you get as much as possible and then stop. Take off the free-play as well. And adjust the couplings inside the access port behind the front seats too.

How old is the cable? The helper spring on the tranny? and the Return spring at the pedal?

[Jdub]

Jim:

The throw is set using the rubber block on the wooden panel that covers your pedal rack. The clevis pin and nuts at the trans bottom are the items used to get your "1.2mm, then 1.0mm" setting for the cable.

Did you notice a bush at the clevis pin, inside the hole? If not there than a pedal rack redo may be in order.

However, the grinding you mention has everything to do with the shift coupler and probably the bushing on the other end of your shift lever, under the shifter. Those are the areas to concentrate on to get the grinding fixed.

John

[marcesq]

Jim:

Your post did not mention whether your pedal bushings are in good shape. If they have not been replaced, and are worn, the clutch pedal shaft grinds down against the hole in the pedal base, making pedal travel rough, and, if bad enough causing adjusting problems for the clutch.

I believe your '78 is the same as my '77. If you can not get the 25mm maybe the pedal stop on floorboard is improperly adjusted.

Before droping the engine check pedal bushings (replace if there is any sign of scoring on the clutch pedal shaft, which if scored must be replaced as well), and replace clutch pedal spring and clutch cable. If no improvement replace helper spring on transmission.

Last put Swepco in the tranny.

WHILE I WAS TYPEING THIS JDUB POSTED SO IT MAY SOUND REPETATIVE

[jamesiii]

Thanks to all!
marcesq: The clutch pedal seems to move smoothly so I don't believe it's a bushing problem...no wiggle and no grinding on the pedal end. Also, I've completely let out the adjustment for the throw at the wooden floor board to it's max (the rubber stop is gone but the stop still works) and I really didn't get any more throw in the cable.

Jdub: Could you be a little more specific regarding the bush at the clevis pin. I did have to adjust the clevis pin to 1.2mm with the clutch cable disconnected, but after I attached the cable and tried to adjust to 1mm I ran out of thread on the bolts (adjusted so there is no thread left on the transmission side, all exposed thread on the firewall side.

yelcab1: I wish I knew how old all of the clutch components were. I bought the car from a dealership who assured me the PO had all the service records. This amounted to an oil change in 1980 and the 1978SC Manuel...nice record keeping! Anyway, the cable looks new (the rubber condom which protects the cable has split and I can see the cable looks really strong, but the helper spring looks rusted. I'm not certain if this is just superficial rust, or if it's rusted to where it's not working properly.

Again, I can't even get close to the throw specified, and I can't get the clutch pedal to return to it's beginning position (i.e. level with the brake pedal)...it stops 2/3 of the way back and I have to pull it forward with my feet/hands to get it into the proper position.

The pedal spring seems fine...no rust and it seems to have some snap left...I'm really starting to think it's a combination of the cable condom cracking and something interfering with the glide of the cable, along with the helper spring, backlash spring not giving the proper "SNAP" to the clutch. But this doesn't address lack of throw necessary to disengage the clutch.

The more I think I get this narrowed down, the more the solution escapes me!

[B]

[Clark Griswald]

You may have more than one problem, but first things first.

You need to get that pedal to return to the proper height when released. It should be about even with the brake.

The problem is almost surely one or both of your return springs. Less likely causes are binding pedal bushings or a bad cable, but much less likely than the springs.

Replace both springs. There is the horse shoe at the trans and the coil one at the pedal. Even if they feel springy, replace them. They feel springy even when bad.

FYI, both these springs work to both return the clutch when released and depress the clutch when you press it. They accomplish these seemingly opposite purposes through a cantilever action. Don't believe me? Then watch their action on a properly working and adjusted clutch mechanism while your buddy presses and release the pedal. Both springs assist in both directions.

And while your at it, go ahead and replace the clutch cable too. It is cheap and easy to do since you are going to be in there anyway. And if it was me, I'd also replace the pedal bushings. This is a bit more work, but again they are cheap and it would be good to eliminate any potential issues.

Once you get the pedal height correct, see what you have. You may be done, or you might need look at some other areas like the shift coupler.

[jamesiii]

Thanks Clark!

I figured on replacing the cable anyway, along with the helper spring and all it's associated componetry. I'll include the bushing as well, since they aren't costly and I might as well tear the hell out of the clutch cable assembly and fix everything in front of the transmission before I actually tackle the clutch or tranny.

Just when I think I'm somewhat completed with all the "big" items to maintain this car I get bit...hard...again! I'm turning into a pretty good mechanic though...almost nothing I'm not willing to at least tackle...screw up...and take a box of the parts to my wrench with an apology and a case of beer!

[Jdub]

Yes, I think I can. There should be a bushing (my car is a '78sc) in the hole into which your clevis pin fits. That little hole is located at what I call the "ear" of the clutch pedal. This ear is part of a shaft that runs through the pedal rack assembly to the clutch pedal proper: the two are joined by the infamous clutch pin.

This is big with me because I was AMAZED to see when I went to rebuild my pedal rack that not only was the bushing gone, but the clevis pin was actually starting to wear an elongated hole in this hole. A rebuild with Pelican's bronze bushing kit transformed the pedal action - you could literally push the clutch pedal down with your finger it was so smooth. This job was complemented by a new clutch cable and helper spring.

John