Clutch Problem

adam911 · 09-10-2010, 05:11 PM

I've just refiited my engine and transmission on my 71 car. It has the pull type clutch unique to the 70-71 cars. I got it in and hooked up, went to connect the clutch cable and found I'd forgotten to set the thrust bearing, so (after an awful lot of swearing) I took it out again, set the thrust bearing and refitted the engine. I then went to depress the clutch and found it to be very stiff, so much so that I didn't want to press the pedal any further for fear of braking the cable. I slackened the adjustment right off and that didn't seem to make any difference.
I've not touched the clutch at all and it has worked fine previously. There's nothing obvious I can find and tomorrow I plan to remove the engine and tranny again to see if I can solve the problem. Before I do that I want to explore what may be wrong. I can only think of two things;

1. I have somehow set the thrust bearing incorrectly. Though I have done this several times with no problems. Is it possible the bearing can be 180 degrees out and cause this problem?

2. When tightening the pivot bolt on the clutch lever, is it possible to overtighten it, though it appears it can only tighten so far and not be overtightened?

Does anyone have any thoughts?

Thanks

Adam

Alan Lindquist · 09-10-2010, 07:13 PM

If/when the engine comes out again, check the condition of the clutch fork. It could be bent/cracked.

Are you sure you have the fork engaged on the bearing correctly? Did you confirm by looking in with a light when the engine mated up to the transmission? If it's not in the groove, you'll have that problem.

Is the actuator arm indexed correctly on the spline for the clutch fork?

Why was the motor out?

adam911 · 09-10-2010, 08:53 PM

Thanks for the reply Alan.

On the 70-71 model you have to set the bearing after mating the gearbox by taking the pressure off the clutch fork (pulling on the fork, the opposite to how it operates) and spinning the bearing by 90 degrees through one of the holes in the gearbox casing. This then aligns the 2 wings on the bearing with the clutchfork. However I was surprised to find there doesn't appear to be anything that locks the bearing in place, just the pressure of the clutch fork on the bearing.

I'm not completely sure what you mean by "Is the actuator arm indexed correctly on the spline for the clutch fork?"
What is the actuator arm? Is it what I'm refering to as the "clutch fork"?

I've had the engine in and out a couple of times due to a repaint, to swap the transmission out and again to replace a noisey differential. Each time before I'd set it up in the same way without any problems.

Adam

adam911 · 09-11-2010, 08:28 AM

Bump

cjmurph · cjmurph's Garage

Adam,
I just did some clutch work on my 71 as well.

When I set the throwout on the clutch fork, I didn't have to pull very hard. In fact it seemed a bit loose to me. I reasoned that when you adjust clutch, it sets constant pressure which maintains the relationship between the two.
Makes me think maybe the pivot changed and actuator arm is now hitting the housing. Can you tell by looking up at the arm if there is room for movement? If helps if somebody else can work the pedal while you're under the car.
I'm not home right now or I could at least grab a pic.
Curt

adam911 · 09-11-2010, 08:58 AM

Hi Curt,

I thought exactly the same thing when setting the bearing, one really doesn't have to put very much reverse pressure on the actuator at all. I figured the tension of the cable must keep it in place, but it does seem a bit tenuous compared to bearings on other cars I've set in the past.
To check the actuator is centered I released the cable and wiggled the arm left and right and it appears to be centered and seated correctly.
I dont have anyone here right now to depress the pedal for me, so I'm thinking I may attach a vice grip to the end of the arm and gently see if I can actaute the the clutch that way. If I can, then I'll take a look at the cable perhaps.
Though ultimately I think I'm going to have to pull the engine again. It's a shame there isn't an inspection cover in the back seats to allow access to the housing appeture to save dropping the engine.

My concern now is the undue stress taking the engine in and out is putting on the fasterners.

Adam

cjmurph · cjmurph's Garage

Quote:

My concern now is the undue stress taking the engine in and out is putting on the fasterners.

Oh how I know that feeling well. I was always in celebration mode that all went well with an install then only to find it all has to come back out again. Tedious.

Dreaded would be the bent or broken actuator arm that lets you set adjustment on the clutch but has "pinned itself" by maxing travel with the arm.
Curt

This helped me.

911 clutch fork (Grady, Tyson, others?)

adam911 · 09-11-2010, 10:11 AM

Well, I just got very lucky.

I put the car on axle stands, removed the wheels and clutch cable. I then found I could put my hand up in the wheel well and get my finger in the aperture and release the bearing. I then was able reset it. Put the clutch cable back on and voila....it works.
It was obviously not set correctly first time round.

Thanks for the help.

Adam