Clutch pedal position suddenly changed after a snapping noise.
 

Hey all,

I was out enjoying a few errands in my 930. I was at a stop light and pressed the clutch pedal in when I suddenly heard a *snap* followed by the pedal suddenly dropping an inch downward towards the floor. The car still drives, clutch engages normally but the neutral position of the pedal (ie. when I’m not pushing at all on the pedal) is now deeper into the floor. What’s happening?


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One of two things:
1) The cross pin which connects the pedal arm to the cross shaft (whose end inside the tunnel is what pulls on the clutch cable) has sheared. So your pedal is more forward compared to the lever in the tunnel. This is not a stable situation - soon it will slip more, and you won't get clutch disengagement. You can fix this, though with difficulty, with the pedal cluster in place. You have to figure out how to hold the cross shaft so you can pull the pedal back so the three pieces of the pin are lined up. Then you drive the pin bits out with a drift. Alternatively, you might be able to force the pedal's end sideways off the shaft - getting the broken parts out then would be easier. New pin, good to go. You can get a substitute pin at a good hardware store, probably. Even a better one than you get from Porsche or Pelican/Porsche.

2) If a couple of strands of the long clutch cable break, either at the swedge at either end, or (as happened to me when the outer sheath got dislodged) where the cable goes from the tub to the transmission) elsewhere for some reason, the cable lengthens some, moving the pedal position down. This, too, is progressive and temporary.

So, can you start the car with it in first, and up and down shift without a clutch? This is dead nuts easy if you know how with a VW bus (I drove a couple of hundred miles that way once), but I found getting the shifts right on the 915 disappointingly difficult, with too much clashing. Though I did get home to Boulder after the cable broke going up Rabbit Ears Pass once. Because you can't count on driving much this way.

I'd get a new cable and a new pin on the way, just to cover your bets. You can inspect the cable to see if it is the issue. Inspecting the pin would be trickier. The "can you move the pedal relative to the shaft, rotation or sideways" approach might be a go/no go there - if any movement, pin is broken.

Someone else may have better ideas, as the pin breaking is pretty common as time goes on. Cables generally are more durable as long as everything is where it should be.

I'm not sure if the 930 pedal box is similar to my 79 SC but there is a helper spring on the outside of the clutch pedal that attached to the pedal box/carrier and I believe if this breaks or comes off, it could change the pedal resting position.
There is also a spring around the shaft between the pedals that I've seen broken before.
Just my 2cent guess.

Thanks,
Scott

Omega spring? May be broken, not separated. Not for long.

Unlikely but Could be the start of a broken clutch lever. Check it out as it is expensive if you loose the omega spring as well.http://forums.pelicanparts.com/uploa...1596974539.jpg

Ask me how I know!
Johan

Wow - add broken lever to the list for differential diagnosis! At least this can be found by visual inspection - you could see the crack which preceeded the break.

My experience with the Omega spring is that when (probably not if) it breaks, all that happens is that you lose its reduction of pedal pressure effect - you have to push harder on the pedal. I discovered this when I was able to push a friend's SC pedal down with my hand, while on my SC no way. It was the center segment of the spring which had broken, as I recall.

But others may have had their pedals behave differently?

I don't think it'll be the omega spring. When my omega spring broke it made a ping sound. The looped end had snapped right off. The pedal position didn't change, it was just way heavier. But it's an easy check as it's an external component.

If the pedal dropped it's almost certainly the spring at the pedal cluster. I had the same exact symptoms last year. I heard and felt a bang through my foot and the pedal dropped a bit with not much else happening. That helper spring helps pull the pedal down when you push in the clutch and when you let go it applies tension to pull it back up to the top.

Take a peak under your carpet, bet you a dollar you'll see parts of a spring at the base of the clutch pedal. Google 930 pedal cluster for photos.

My guess, too.

Update. I removed the wood floorboard and found this rolling around.

Which spring is this?
https://uploads.tapatalk-cdn.com/202...74dfcc9a64.jpg


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Yep, knew it, that's the clutch helper spring. Our host carries them for all variations and there's a number of threads on replacing it.

Spoiler alert: It's a *****, but there are tricks to make it easier. Usually it ends up being one of those things where you end up rebuilding the whole pedal cluster. That's what I did and man it's so much nicer now, all powder coated and lubricated with new bits? Oh man I love it.

Can I just replace the spring or should I follow the Pelican guide and give the entire assembly an overhaul? I ask this because up here in Canada the driving season is short and the idea of doing a big project in prime driving season is depressing.


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You can just replace the spring. Search this forum for tips. You can find pictures of how guys have expanded the new spring by jamming washers between the coils with enough force to force the coils to get farther apart. When you have it long enough, you can slip the end you didn't hook up on its peg.

Once you get it in place, you pull the washers out with pliers or vice grips, the spring tightens, and you are good.

Without a trick like that you need an old drum brake tool which allows you to lever a hook end over its pin so that it slides down the tool and into place. Not a lot of room for doing that.

I had no idea that spring could break. Always learning something here.

If any part of the clutch release system fails, (cracked release lever, broken clutch cable strands, clutch release pivot bolt, excessive wear, etc.), that will affect clutch disengagement and thus cleanly disengaging/engaging gears.

Sherwood

I’ve never had an issue with engaging/disengaging gears etc. I’ll inspect everything as best as I can to make sure all looks good.

Thanks.

Btw love the idea of slipping washers between the coils of the spring to lengthen it prior to placement, what a cool idea.


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This is what happened to my 930. The spring broke. The spring is to keep the pedal at it's top resting point so it doesn't sit on the cable putting pressure on the throw out bearing.

I think this is what happened to the OP's clutch pedal.

Can this spring be purchased? I didn't see it here on PP.

Here's the part#
https://nemigaparts.com/cat_spares/etka/part/93042300500/?fbclid=IwAR1Mf2NQSH-xVqo4zlo2Ll326AdPUVUSQRIZnsgm6GI90C6B3eWG0Fbw1wM

If this is a part that fails then I'm thinking of getting a spare in advance. Looking at the PET for 1983 I note on pages 203/4 that there is a clutch return spring (35) with part no. 911 423 305 06 for an SC- Turbo is different. I will be contacting my local Porsche dealer here in the UK to see if it's available. I have often be amazed at what you can buy for this cars at the dealer.

If that spring broke, it really is best practice to pull the entire pedal cluster and rebuild it. The car is 33 years old. If that spring is worn out enough to break, the rest of the components are likely worn as well. I bet you will be surprised at the wear on the pins and bushings of the pedal cluster.

It is a pain in the butt to do it. If you place to keep the car and drive it long term, fix it right.

Tip one, remove the seats to get some room to fit into the footwells.