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Clutch Pedal Roll Pin Failure (or, the clutch ain't dead yet!)

 
Old 10-10-2016, 07:24 PM
  #31  
Goughary
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Found some pics. Note the bushings are bent from removing them- these are the old ones...and if you see at the bottom of the pic, the clutch with the splined end. And then the box reassembled with all new parts.

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Old 05-27-2018, 05:00 PM
  #32  
sooner964
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About two weeks back, I went out to start up my car and my clutch did not return all the way up when I released it after starting. I was able to pull it back up by hand, and then it operated more or less as usual the rest of the day. However, it did seem to not engage as smoothly or predictably, so I knew something was wrong. It led me to this thread.

Last night, I spent several hours out in the garage trying to fix this problem. I pulled the pedal assembly out, which was not exactly easy, hoping to find the roll pin ready to give way. What I found looked like this:



That struck me as odd. It looks like at some point in the past it was soldered or somehow adhered to the opening. If I look at the back side, I can see that at least half of the pin is gone:



So I thought, OK, this should be easy. First, I began by trying to punch it out with a center punch and hammer. No luck. I then thought, OK, a drill will do it. No luck.. most of the bits I tried ended up breaking, and they are titanium, brand new bits I bought specifically for the job. I then thought, OK, maybe a touch of heat will get it to loosen its bond, and then I can knock it out. So I used my soldering iron to heat it up, and then went back to the center punch and hammer. This yielded no appreciable result, and then I wondered if maybe I was shooting myself in the foot and causing whats left of the pin to expand under heat. I have maybe opened up the hole a little bit, but I also think I now have a bit of broken drill bit lodged in there. There is enough roll pin in there still though that when I loosen the screw at the base of the clutch pedal to attempt removing the clutch shaft from the brake pedal, it is locked in firm and tight. I am convinced the roll pin is my issue, and I can visually see that the bushings are toast, as well.

But, try as I may, I am having no luck getting the roll pin out. This is what I'm looking at now:



I'm basically to the point where I'm ready to just buy a new pedal assembly and chuck this one out, unless anyone has any suggestions?

This has been a very frustrating project and I can't believe Porsche used such a design. The 993 pedal assembly seems so much more well thought out. This must not have been part of the touted "85% brand new" parts.

For those that wish to attempt this project in the future, it would probably help immensely to remove the driver's seat. When I get to the point that I can put it back in, that is what I intend to do. Also, I would unbolt the master cylinder before unbolting the base, otherwise you will have to rebolt at least one of the base studs or you will have no way of getting torque on the master cylinder nuts. Mine were all very tight and difficult to break loose. Also, it is a very tight space and requires a variety of wrenches/nut extenders. And then once you have all of the nuts off, actually getting the pedal assembly out is another trick. Basically, I took a flat bladed screw driver, wedged it under the assembly and began pushing upwards to get it off the studs. Then you can start to pivot and work out the Master Cylinder. Also, for the point where the throttle linkage attaches to the pedal cluster, I suggest that before you start working the pedal cluster out, disconnect the safety clip, remove the washer at the end, and slide it off. I forgot to do this and had to jimmy the whole assembly back to a point I could get my hand in there. My visions of being able to drive the car in half an hour after starting the project and revel in the glory of a new roll pin and bushings were way delusional, lol.

Now if I can just get the pin out to replace.. any suggestions? Perhaps there is a way to remove some of the assembly (springs?) so that I can get to it from the back side? I would need for it to be freely moving so that I can rotate it to a point that I have clear, unobstructed access to the other side where I can clearly see the hole. Then maybe my hammer skills will pay off.

At least before I started this project, I managed to successfully replace the front and rear windshield wipers in less than five minutes, so I accomplished that. Start easy, right? lol
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Old 05-27-2018, 10:14 PM
  #33  
Goughary
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Make sure you are using a pinch that is small enough to fit through the hole on the kinematic lever. Ie- take a look at a new roll pin and make sure the punch is slightly smaller than that.

Then- hit it a lot harder. You'll be surprised at how much force an old roll pin needs to break loose. Squirt it with pb blaster and let that settle in first.

I always run safety wire through the center of the new Roll pin after reassembly btw. Just to make sure that it can't back out and in the event of a future rollpin failure, it will have some support.

Further - the reason we break rollpins is because of the clutch pedal stop. Make sure it's the clutch pedal stop that stops your pedal travel. Not the back of the master cylinder. That will make sense when you think it through...

Good luck. Feel free to call or pm if you need some help with that.
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Old 05-29-2018, 03:03 PM
  #34  
sooner964
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Originally Posted by Goughary View Post
Make sure you are using a pinch that is small enough to fit through the hole on the kinematic lever. Ie- take a look at a new roll pin and make sure the punch is slightly smaller than that.

Then- hit it a lot harder. You'll be surprised at how much force an old roll pin needs to break loose. Squirt it with pb blaster and let that settle in first.

I always run safety wire through the center of the new Roll pin after reassembly btw. Just to make sure that it can't back out and in the event of a future rollpin failure, it will have some support.

Further - the reason we break rollpins is because of the clutch pedal stop. Make sure it's the clutch pedal stop that stops your pedal travel. Not the back of the master cylinder. That will make sense when you think it through...

Good luck. Feel free to call or pm if you need some help with that.
Hey Goughary,

Thanks for the reply! I'll double check on the size of my punch but I think it should be slightly smaller. I guess I will have to try hitting harder. Looking at it, I can't even convince myself I'm hitting the right thing. I should have some time out in the garage tonight, so I'll try giving it a bit more encouragement, as it were.

What do you mean by "safety wire", if you don't mind me asking?

And I will have to look at the clutch pedal stop. Do you mind giving a bit more detail on what that looks like and how to ensure it is stopping the clutch and not the master cylinder? I'm guessing since I seem to be missing at least 2/3 of the roll-pin on the backside, it must not be functioning properly. This is a job I don't particularly want to tackle again anytime soon.

Depending on how it goes, there is a strong possibility I will be taking you up on sending you a PM to get more guidance.

I appreciate it, thank you!
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Old 05-29-2018, 03:51 PM
  #35  
Goughary
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For the pedal stop...the adjustment is on your floor board behind the pedal. If the pedal stops at that stop, this is good. If the pedal stops before the stop, this is bad. This means the shaft in your master cylinder travels to the end inside the master and stops. This puts huge sheer force on the rollpin and snaps the rollpin.

For the wire, see the pic. This type of thing. There are many brands. Run a couple of loops through the rollpin after install, twist the end and cut it so it's out of the way. This will help in the event of a rollpin failure.

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Old 05-29-2018, 05:01 PM
  #36  
AOW162435
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sooner,
It looks like someone plug welded the lever to the shaft at some point. If that's the case, a small punch & hammer will not work.




Andreas
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Old 05-29-2018, 05:32 PM
  #37  
sooner964
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Originally Posted by Goughary View Post
For the pedal stop...the adjustment is on your floor board behind the pedal. If the pedal stops at that stop, this is good. If the pedal stops before the stop, this is bad. This means the shaft in your master cylinder travels to the end inside the master and stops. This puts huge sheer force on the rollpin and snaps the rollpin.

For the wire, see the pic. This type of thing. There are many brands. Run a couple of loops through the rollpin after install, twist the end and cut it so it's out of the way. This will help in the event of a rollpin failure.

Attachment 1282379
Goughary,

Awesome, thank you for the clarification, that really helps a lot! I will have to check that when I get the assembly back in.

And that makes total sense now with the wire. That is a really good idea!

Originally Posted by AOW162435 View Post
sooner,
It looks like someone plug welded the lever to the shaft at some point. If that's the case, a small punch & hammer will not work.




Andreas
That's what I was afraid of when I saw it... but I hoped maybe it was just epoxy of some sort. But the way it has reacted to my attempts, I was beginning to wonder if that was the case.
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Old 05-30-2018, 03:05 PM
  #38  
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Just a thought - if the shaft is actually welded to the kinematic lever, the shaft can't rotate and therefore your rollpin can't be broken. If the shaft can rotate, then if it's a weld, then the weld is broken loose anyway.

Also- i think i have an extra used clutch pedal around. So if you happen to damage the shaft in some way, give me a shout and I'll look for it. Regardless they aren't very expensive new...so hammer away!

Fwiw- the last one i did, the rollpin wasn't responding to a normal hammer- so i grabbed a bigger one and after a couple whacks...it broke loose and then tapped out ok. Granted- that pin had been in there 30 years.

One more note. If the kinematic lever has rotated on the shaft, the hole isn't straight all the way through- this will also preclude the rollpin from coming out, as it has no place to go. So be sure to do your best to make sure it's aligned properly- not easy to do blind, but if the kinematic lever can rotate a bit on the shaft- roughly half way in either direction is a good place to start.

If that doesn't make sense...call
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Old 05-31-2018, 04:24 AM
  #39  
Peteinjp
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Can anyone tell from these shots if this is a 993 or 964 pedalbox?





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Old 05-31-2018, 08:51 AM
  #40  
Rocket Rob
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The clutch end lever (bell crank) is held onto the shaft with a roll pin in the 964 pedal assemblies while its attached with a spline and nut on the 993.

I can't tell exactly from your photos but it looks like a 964 to me.
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Old 05-31-2018, 08:56 AM
  #41  
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I’m thinking I see a roll pin....

thx.

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Old 05-31-2018, 09:38 AM
  #42  
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That's a 964 pedal box.
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Old 05-31-2018, 02:22 PM
  #43  
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Just don't replace the roll pin with an M6 bolt. Did that in mine and it broke after a couple of weeks...
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Old 06-03-2018, 10:08 AM
  #44  
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So I just realized that not only was the roll-pin welded at the front entry hole on the kinematic lever, but the lever is welded to the shaft at the end, too, as Andreas mentioned. Perhaps that was obvious, but I think I was so focused on the roll-pin itself, I didn't notice the weld at the end of the shaft. That weld is very obvious in the picture looking at the backside of the kinematic lever where there roll-pin shaft is empty.

The lever does not rotate in place on the shaft, so the weld is not broken, which I guess could be a "permanent" fix. However, I can see that the bushings are in bad shape, and I can't see a way to replace them with the lever welded to the shaft. Can the issue be proscribed to the bushings alone? If the lever is welded to the shaft, the lack of a roll-pin all the way through should not really be an issue, correct?

Maybe my issue is more to do with either the Master or Slave Clutch Cylinders, or needing a bleed?

I don't like not being able to replace the bushings, and it has me thinking I need to replace with a whole new pedal assembly, either 964 or 993. I've found a few 993 assemblies for sale from dismantlers, but I haven't found a 964 yet. Goughary, I've been reading through your suspension madness thread where you discussed the 993 pedal box and that you ended up having hanging issues and I was wondering if you were ever able to resolve them? Maybe it would be better if I found a used 964 assembly and replaced the pin and bushings with the parts I bought for mine?
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Old 06-03-2018, 10:37 AM
  #45  
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I wonder if a 964 pedalbox could be hacked to fit the 993 pedal/bushing/lever assembly.... Probably not but in any case you don’t need a whole new box- just the clutch pedal assembly....... grinding of welds required.

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