Clutch Pedal Returns, Stops, Clicks then comes up another inch!

[Bill Jennings]

Hi All,

1977 Carrera 3.0 120000 miles, new clutch 2 years ago/10000miles since, just replaced cable and clevis retainer, omega spring, short arm and associated spring.

Replaced parts due to amount of force needed to depress clutch pedal now much easier to depress pedal!


Clutch and pedal operates normally except on return as pedal comes up to within one inch of brake pedal position, then stops momentarily, makes a click sound then comes up another inch! Pedal operates normally when depressed.

Pedal did not do this before replacing above parts.

Cheers
Bill

[gregwils]

It would be helpful to know where the clicking noise was originating - at your feet vs the back of the car. I have two guesses, both assume the noise is coming from your feet.

My first guess would be that the cable is not adjusted correctly. I had a similar condition on the pause, but the pedal did not always fully return. I had incorrectly installed the cable at the clevis pin. Did you use Wayne's book or a shop manual to get the measurement correct?

My second guess is that in the process of working around the pedals, one of the pedal cluster bushings got damaged. This is a low probability, but it could be the cause.

Where is the noise originating?

[Bill Jennings]

Greg,
I'm pretty sure the sound is from the pedal area.
I changed the amount of thread at the clevis as 8mm made the pedal low to the floor so I put it up to 12mm and now the pedal returns to the same height as the brake pedal albeit after the aforementioned pause. What should be the correct amount of thread through the clevis?
Cheers
Bill

[mreid]

If you are threaded too far into the clevis, it will cause the problem you are having as the threaded end of cable catches on the pedal post. Try backing it out a few turns and see if you have the same problem.

[Bill Jennings]

Mreid,

I will try that many thanks.

I will do it right after I get home after getting this altered to fit!

Cheers
Bill

[Greek55]

If your car has a helper spring you may need to adjust the adjustment screw. They started putting helper springs on 911's sometime around 1977, 1978.

[cary]

Make sure the cable is fully tensioned before you set the freeplay.
Takes a bit to get the Omega spring tensioned.

[Bill Jennings]

I admit to being unsure if I am setting up the adjustment the right way. I have waynes book as well as a bentley.
My car has the omega spring which is new.
When setting the gap on the bolt through the short arm I have been levering the long arm forward with a pry bar against a rib at the bottom of the tranny in order to get that bolt close enough to adjust. When I lever the long arm forward the omega springs rotates away from the heat exchanger and seems to rest on a small bracket that is under the spring and attached to the bottom of the tranny.
Is this the correct procedure?
I will take some pics to show what I mean.
I need to jack the car up again as I took her to the muffler shop yesterday to have my GT3 style exhaust modified the story of that is in another current thread Had custom muffler made which does not fit?????
I also need to readjust the cable at the clevis end after checking that is where the pedal is being held up.
Cheers
Bill

[Bill Jennings]

Hi All,

Ok this pause at the top of the pedal travel is not at the pedal end as the pedal turns freely on the shaft with the cable disconnected at the clutch arm end. Also the spring at the pedal is strong as the pedal flys to the floor once it is tipped in that direction.

So I am now assuming I have an adjustment problem at the clutch arm end which looks like this before I disconnected it.


And looks like this once disconnected.



Then I adjust the bolt in the small arm to 1.2 mm, attach the cable by getting enough play by prying the long arm forward and tighten the bowden adjuster till I have 1mm gap on the small arm bolt.

Now it looks like this



I notice that the adjustment is different now at the small arm bolt and at the bowden adjuster than before. I am unsure what I did differently this time.
The clutch pedal now seems to go right to the top as it should.
I cannot check if I have the required 25mm travel in the cable as I am here alone but will take her around the block to see how it is.

Cheers
Bill

[cary]

Let's just say I had some issues with a new flywheel and pressure plate the last month or so. Long story.

But I was taught a new way to set the clutch. Pretty simple. Unhook the cable. Remove the freeplay arm and little spring. Attach the cable. Now tighten the cable so that it just comes off the Omega spring stop plate. Just push on the black cable cover to test the tension. You'll hear it start to click when you've gone far enough. This tensions the Bowden tube and gets all of the slack out of the cable.
Now put back on the freeplay arm and spring. Set to 1mm and you're good to go.

Let's just say my trainer was is a pretty well known Porsche mechanic here in Sherwood.

This is on a 77 Carrera 3.0 with original gear box same as yours.

[Ayles]

Amazing and timely pictures!! Thanks for posting.

[Bill Jennings]

Update
Was raining heavily here last night so never got to take her round the block.
Wife returns thursday so can measure cable travel then which I'm told should be done before driving anyway.
This is my second 911 the last one was a 79 SC and I have always struggled with adjusting the clutch.
On the SC I had to compress the omega spring and use a cable tie to hold the tension just to get the long arm & omega spring on the shaft as the heat exchanger was in the way if I didn't do this. The only other way to get it on was to lever the omega spring forward while pushing the long arm upwards onto the shaft. that method usually resulted in the screwdriver slipping off leaving some skin on the spring. On the C3 the whole gubbons just slides on, no tension in the omega spring at all, but the small arm adjuster is too far away on the only spline I can use so I then lever the long arm forwards, the omega spring rotates and it seems to be held in forward position by a very small bracket bolted to the transmission case under the omega spring. In this position the omega spring is in tension.
One of the problems I have had installing the long arm on the C3 in this way is that I seem to end up with the long arm in a different position at different times making the adjustment incorrect later in the process. I think the return problem in the pedal I have been dealing with is related to this issue and it would seem this time I have got it right. But what am I doing wrong when I get it wrong if that makes sense. I does not seem logical to me that what I am doing is so random.
The new omega spring is genuine Porsche with the correct part number from the PET and so is the new short arm I installed.
I also do not understand why the installation process is so different from the SC and the C3 either.

Carey,
Just reread your post again it sounds like using your method would remove the randomness of my method as tensioning the cable in this way is incremental rather than levering the long arm the way I have been. I wonder if I have some play that makes the long arm hang up in different positions that would explain the random positions the arm gets set in. When you use your method does this give you the required 25mm of cable travel as well?
Cheers
Bill