Something just snapped in my clutch.

[autobonrun]

Pulling out of my driveway and shifting to second gear, I felt and heard a snap, and the clutch went all the way to the floorboard and stayed there. Did a quick u-turn and coasted it back into the garage still in second gear. I assume it is either a spring or clutch cable. Any idea which is the most likely? If it is a spring, where is it physically located? I guess I'll spend Memorial day getting it up on jack stands. If it was going to fail, it couldn't have picked a better place. Gotta love those SC's for taking care of their owners.

79SC

[Quicksilver]

Is the clutch engaged or is it free wheeling? If it is free wheeling and the pedal went to the floor then it would have to be the pressure plate. That is the only place where the 'release system' and the actual 'engine torque transfer system' combine. It would be to hard to believe that two things actually failed at once.

If the clutch is engaged then it is most likely broken clutch release cable which would be fairly common.

Wayne

[Early_S_Man]

Most likely the cable, but also could be the pedal shaft/arm, or throwout bearing operating arm inside bellhousing ...

Pull the front carpet, first ... and check out the connection at the clevis to pedal-shaft-arm connection.

It should be easy to determine just how far pedal motion is being transferred along the path ... with an assistant to operate the clutch pedal by hand [back and forth] while you look on the underside ... after the back end is up on jack stands!q

BTW, check your body-to-transaxle ground strap while it is up in the air ... ground strap failure can lead to very rapid clutch cable failure as it becomes the major starter current path, and the cable soon turns blue and crystalizes, then fails as you described!

[gerard vaglio]

I have the same car and it had the sme problem last year. You might want to look at the roll pin. On the far right of the pedal assembly there is a pin that goes through the pedal assembly shaft . When you move the clutch pedal with your hand up and down if it moves independently from the pedal assembly shaft you've located your problem.

If however, the pedal assembly moves when you move the clutch pedal with your hand the problem is farther down the line, like clutch cable or something. Work backwards from there untill you locat whats not moving with the clutch pedal.

If the roll pin is the problem, dissasemble the pedal cluster, bring the clutch assembly to a porsche place and have them drill out the old one and install a new one.

While your in there you might as well use this opportunity to put in new bronze bushings for the entire pedal assembly. The bronze bushings are like five bucks and the roll pin costs even less.

Don't bother trying to remove the roll pin yourself, unless you own a machine shop! Ask me how I know.

Let us know what you find in there, if I can help I'm happy to save you the frustration I went through.

[Brent 930]

Could be several things like the guys mentioned above, just pray it's not your TOB. I doubt it will be any levers since there nearly un beakable.

I had this very thing happen to me on the track of all things and quickly realized it was most likely my TOB which it was come to find out later. Hell, I put it in 2nd and drove the car home. It should be obvious after checking things out if the problem is external or internal.

Goodluck

[autobonrun]

Thanks for all the advice. As soon as I finish bar-b-q'ing I'll get it on the stands and take a look underneath. The clutch is not freewheeling, it remained in second gear. That sounds like a good thing. Hopefully that means its not the pressure plate or TO bearing. I did lift the carpet and the spring from the pedal to the first connector shaft is still in place. I can see that piece rotate, so it has to be either in the cable or further back. I'll check this evening.

Warren, I'll also check that ground strap. Never heard of that before but it makes sense and it did fail right after I started it up.

[Brent 930]

One more thing, when my TOB pulled out I was wondering why since there was only 10k miles on it? After I replaced the clutch (first time, what fun) it still didn't make sense why. The spring under the floor board that attaches to the the clutch pedal where you can adjust the tension wasn't letting the lever come back all the way. What this means is the TOB was always getting pressure which probably made it go bad alot sooner. So when I tried to release some tension the spring mechanism broke. I thought, good, it was just causing me more trouble than it's worth. BUT, I realized I needed something there so I went to the hardware store and made my own device that works well. Every time I push the clutch pedal in and release it the pedal goes back to the same spot every time. So when the clutch is engaged there is no extra pressure riding on the TOB and my clutch kit should last alot longer. Something to be aware of now before it's too late.

[Wayne 962]

Jack up the car, and have someone press the clutch in while you look underneath - that will reveal a lot...

-Wayne

[autobonrun]

Ok, I got under the car and the clutch cable is still attached to the clutch release lever. Both springs on it are good and still connected. However, there is a lot of play in the clutch cable; I can move it back and forth by hand. I attached a wire to the clutch pedal and had my son move it back and forth. The clutch release lever did not move nor did the clutch cable under the car. So I assume if the clutch cable is not broken at the clevis connector, it must have broken somewhere along the length. I'll try to tear into the pedal cluster later to make sure it's the cable and not where it attaches to the clevis.

Brent, my car has a metal piece at the top of the floor housing that serves as a mechanical stop for the clutch pedal. It maintains the same return position each time for the clutch pedal.

[autobonrun]

After removing the floor board, I'm able to see the problem. The clevis locking pin completely sheared off. In addition, the hole through the clutch pedal lever where it attaches has widened to the point where it has almost worn through. I've attached a photo of the clevis pin and lever. Immediately above the pin, you can see the clutch pedal lever.

Is this failure a sign the helper spring is not doing much helping? Also, can the clutch pedal lever be replaced without replacing the entire pedal cluster? It does look like the entire pedal cluster will need to come out to reach this lever on the end. Since I need to loosen the clutch cable at the tranny just to move the clevis locking nut forward enough to access it, I think I should also replace the clutch cable, since it is the stock cable from 1979. Looking at my maintenance records, I see the helper spring was replaced in 1990. Given my mileage, these are the parts I think should be replaced now:

1) helper spring
2) clutch cable
3) clevis
4) clevis locking pin
5) clutch pedal lever

Thoughts and comments will be appreciated.

Wayne, I hope all these parts are stock.

[Zeke]

I'm sure you will eventaually find that changing that out will be easier with the cluster out of the car. The roll pin is not a fun job while laying in the floor of the car. Additionally, the shaft won't slide out due to the tunnel being in the way.

If it were me, and I refused to remove the cluster, I might be able to weld up part of the hole and redrill it. The metal will change with the heat and it may not last as long, but a quicker fix since I have a MIG welder. I'd have to be quick about it and have lots of fire protection and cooling to keep from melting the bushings.

Really better overall to remove the cluster.

BTW, that's one of the cleanest clusters I've ever seen. Maybe too clean. You ever put any grease on those parts?

[autobonrun]

Originally posted by Zeke


BTW, that's one of the cleanest clusters I've ever seen. Maybe too clean. You ever put any grease on those parts?

Thanks, I pride myself on having a clean cluster.

But to your question, I have never greased these parts. In fact, I've never had the floorboard up. Obviously I screwed up on this aspect of maintenance.

Welding is an option I'll consider. However, after reading Bentley, I think I will go ahead and remove the cluster. Accessing the front two bolts will be the most difficult part since I don't have a lift. I have a feeling though that once I get the cluster out, I'll probably just replace the parts and do it right.

[Zeke]

Good. Glad you're gonna do it right. The nuts on the cluster studs are a piece of cake. Just take off the pan and they'll be looking right at you. You need to take 2 bolts out of the gas pedal and get that out of the way. You don't have to raise the car that much to be comfortable while removing the cluster nuts. The master cylinder just stays in place by itself.

The usual care while under the car.

[MBAtarga]

Go ahead and buy the pedal cluster bushing set as well - "while you're in there syndrome..."

[Brent 930]

WOW!, how often does that happen? Though I have never taken the cluster out it would be wise to do so for that job.

[Jim Chambers]

I just rebuilt the cluster in one of my cars yesterday. About the sixth one I've done so it went pretty fast. The hole in your clutch shaft lever began to wear and weakened your clevis pin because the plastic bushing wore out and disappeared. If you re-bush (7 bushings) the cluster with the bronze bushings you might be able to reuse the existing clutch lever. Obviously new would be better. Your biggest challenge will be driving out the roll pin which holds the clutch pedal on. You need a solid bench/vise and a big hammer and proper sized blunt drift punch. Otherwise take the cluster to a Porsche shop or machine shop with a press.

[autobonrun]

Originally posted by Jim Chambers
I just rebuilt the cluster in one of my cars yesterday. About the sixth one I've done so it went pretty fast. The hole in your clutch shaft lever began to wear and weakened your clevis pin because the plastic bushing wore out and disappeared. If you re-bush (7 bushings) the cluster with the bronze bushings you might be able to reuse the existing clutch lever. Obviously new would be better. Your biggest challenge will be driving out the roll pin which holds the clutch pedal on. You need a solid bench/vise and a big hammer and proper sized blunt drift punch. Otherwise take the cluster to a Porsche shop or machine shop with a press.

Good advice. Gerard earlier gave similar advice. I'm ordering parts today and will try to remove the cluster tonight. I'll try to remove the roll pin myself but if it gets too difficult, I'll just take the entire setup to a Porsche shop and have them do the rebuild. Then I'll do everything else.

thanks again.

[Jdub]

That's the best pic of the clutch "ear" going south I have seen yet.

You will need to have a dollop of weld put in to round up that hole again. Only then will you have the support of the clutch pedal section to support whatever (plastic, brass) bushing you put in there. No way around that: you have go to have that support there for the bushing to do its job.

Everyone with a 915 is facing this situation. A rebuild of the pedal rack, new clutch cable, and new horseshoe spring will AMAZE you. These cars can have very, very light clutch feel if you treat them right.

John

[chrisp]

I went through this about 6 weeks ago. However mine was discovered while I was doing preventative maintenance during my clutch cable change. I posted a thread warning who ever chose to read it and was hoping that everyone would read it. I guess it's impossible to read everyone. Sorry that you didn't see my post. At least it didn't cause an accident or require an expensive flat bed ride home.

[Jim Chambers]

One other thought. Pay attention to the orientation of the two springs before disassembly and also make sure they are not broken. I had a broken clutch spring which I had to replace. Fortunately I had one on hand.
The clutch spring causes that pedal to go to the floor when disconnected from the cable. The brake spring keeps the brake pedal up.