Clutch Pedal Roll Pin Failure (or, the clutch ain't dead yet!)
#46
Race Car
I may have a 964 clutch pedal that i can sell yu. Then you would just need a new 964 kinematic lever.
The 993 pedal box clutch hanging issue i never worked out, though i gave up without spending too much time. In all likelihood, it would never be an issue in a 964 C2. It was clear that as soon as the pressure pump turned on, the pedal came right up. Now- for full disclosure, i also need a new pressure bomb, which at the time, i wasn't aware that i needed a new bomb. And i subsequently replaced my pressure pump, as mine failed. Both or either of those problems would have exasperated my probs w the 993 box.
So - back to yours. If you have a ton of play in your clutch pedal, and REALLY need to replace the bushings, then hack saw out that shaft, and replace the shaft and the lever. If not, then reinstall and look elsewhere to resolve your issue.
Regardless- if you want a rebuilt 993 box, i have that box and a few different iterations of the 993 kinematic levers. And like i said, i have an extra 964 clutch pedal to sell. Either or both will be cheaper than eBay. Pm me if you like.
The 993 pedal box clutch hanging issue i never worked out, though i gave up without spending too much time. In all likelihood, it would never be an issue in a 964 C2. It was clear that as soon as the pressure pump turned on, the pedal came right up. Now- for full disclosure, i also need a new pressure bomb, which at the time, i wasn't aware that i needed a new bomb. And i subsequently replaced my pressure pump, as mine failed. Both or either of those problems would have exasperated my probs w the 993 box.
So - back to yours. If you have a ton of play in your clutch pedal, and REALLY need to replace the bushings, then hack saw out that shaft, and replace the shaft and the lever. If not, then reinstall and look elsewhere to resolve your issue.
Regardless- if you want a rebuilt 993 box, i have that box and a few different iterations of the 993 kinematic levers. And like i said, i have an extra 964 clutch pedal to sell. Either or both will be cheaper than eBay. Pm me if you like.
#47
Rennlist Member
I've had an ongoing issue with my clutch for 2 years now. Clutch pedal got lower and lower, until I ultimately lost the pedal all-together. Inspection revealed the roll pin backing-out in the front. I hammered it back in, and all was well for about 6 months. Pedal started getting lower again. Inspected roll pin again. Was backed out a bit. Hammered back in. All good, but not quite "right". After 3-4 more backing-out events, I was left with a very low clutch even after hammering the pin flush.
Yesterday I decided to remove the pedal assembly and inspect properly. Sure enough, the roll pin had broken in the middle. Even the though the forward-facing portion of the roll pin was flush, the back side has backed-out almost completely. I hammered-out the remaining pin, then pressed-in a new roll pin. Oh my god! I had forgotten what a properly functioning clutch pedal felt like! I had been driving the 964 less and less, as Long Island traffic can suck, and a low clutch pedal made the experience rather annoying. Now I'm ready to sit in traffic for hours if I have to. It honestly fells like a new car. Such an easy fix. Took me maybe 2hrs, start to finish, having never removed a pedal assembly in a 964 before. Could probably repeat in less than an hour now.
Yesterday I decided to remove the pedal assembly and inspect properly. Sure enough, the roll pin had broken in the middle. Even the though the forward-facing portion of the roll pin was flush, the back side has backed-out almost completely. I hammered-out the remaining pin, then pressed-in a new roll pin. Oh my god! I had forgotten what a properly functioning clutch pedal felt like! I had been driving the 964 less and less, as Long Island traffic can suck, and a low clutch pedal made the experience rather annoying. Now I'm ready to sit in traffic for hours if I have to. It honestly fells like a new car. Such an easy fix. Took me maybe 2hrs, start to finish, having never removed a pedal assembly in a 964 before. Could probably repeat in less than an hour now.
#48
Seared
Rennlist Member
Rennlist Member
I've had an ongoing issue with my clutch for 2 years now. Clutch pedal got lower and lower, until I ultimately lost the pedal all-together. Inspection revealed the roll pin backing-out in the front. I hammered it back in, and all was well for about 6 months. Pedal started getting lower again. Inspected roll pin again. Was backed out a bit. Hammered back in. All good, but not quite "right". After 3-4 more backing-out events, I was left with a very low clutch even after hammering the pin flush.
Yesterday I decided to remove the pedal assembly and inspect properly. Sure enough, the roll pin had broken in the middle. Even the though the forward-facing portion of the roll pin was flush, the back side has backed-out almost completely. I hammered-out the remaining pin, then pressed-in a new roll pin. Oh my god! I had forgotten what a properly functioning clutch pedal felt like! I had been driving the 964 less and less, as Long Island traffic can suck, and a low clutch pedal made the experience rather annoying. Now I'm ready to sit in traffic for hours if I have to. It honestly fells like a new car. Such an easy fix. Took me maybe 2hrs, start to finish, having never removed a pedal assembly in a 964 before. Could probably repeat in less than an hour now.
Yesterday I decided to remove the pedal assembly and inspect properly. Sure enough, the roll pin had broken in the middle. Even the though the forward-facing portion of the roll pin was flush, the back side has backed-out almost completely. I hammered-out the remaining pin, then pressed-in a new roll pin. Oh my god! I had forgotten what a properly functioning clutch pedal felt like! I had been driving the 964 less and less, as Long Island traffic can suck, and a low clutch pedal made the experience rather annoying. Now I'm ready to sit in traffic for hours if I have to. It honestly fells like a new car. Such an easy fix. Took me maybe 2hrs, start to finish, having never removed a pedal assembly in a 964 before. Could probably repeat in less than an hour now.
Andreas
#49
Rennlist Member
I was totally going to do that! When I went to get the drift set, I was supposed to get safety wire and safety wire pliers. Guess what I forgot to get? Oh well.
#50
Does anyone have a list of sources for new/rebuilt or reliable used 993 pedal box assemblies? I got one from a breaker in England but it is in pretty wretched shape.
Thanks
Brendan
Thanks
Brendan
Last edited by brendanm; 06-12-2018 at 08:38 PM. Reason: spelling
#51
Race Car
Update on the interestingly welded 964 pedal box...
I had a 993 box that i had rebuilt hanging around , so sooner964 and i swapped boxes. Why would i have done this? God only knows...but i knew it would be fun, and i have an extra clutch pedal that needed a box...and i figured if i rebuild this box, I'd have an extra around for when someone needs a rebuild they can pull in and simply swap.
Sooooo- here we go...
That's the end of the shaft. I had to first grind off the welds..thankfully they weren't very good...
And then with a hammer and wide punch...it broke loose...
And apart it came...
I couldn't get the other half of the rollpin out, so I'm calling this kinematic lever a gonner. If anyone has an extra laying around, feel free to pm me.
So that's it. I have a bunch of spare parts for pedal boxes, and I've got a few sets of bushings and rollpins, so once i locate a kinematic lever, I'll make a good box out of this one and use it to help some poor 964 soul in need when he inevitably breaks his rollpin.
The roll pin- just to drive it home- breaks in all of our cars because we don't have the clutch pedal stop on the floorboard set properly. If your clutch pedal travels too far, the piston in the clutch master hitting the back wall of the master is what stops the pedal travel. When this happens you are putting huge sheer force on the rollpin and it cracks and then breaks.
This is a particularly important point for all that have bought a Rennline alluminum floor board, because you have to swap all the parts from the oem floorboard to the alluminum one. And most people don't - in my experience. So- if you have no pedal stop, install one.
I had a 993 box that i had rebuilt hanging around , so sooner964 and i swapped boxes. Why would i have done this? God only knows...but i knew it would be fun, and i have an extra clutch pedal that needed a box...and i figured if i rebuild this box, I'd have an extra around for when someone needs a rebuild they can pull in and simply swap.
Sooooo- here we go...
That's the end of the shaft. I had to first grind off the welds..thankfully they weren't very good...
And then with a hammer and wide punch...it broke loose...
And apart it came...
I couldn't get the other half of the rollpin out, so I'm calling this kinematic lever a gonner. If anyone has an extra laying around, feel free to pm me.
So that's it. I have a bunch of spare parts for pedal boxes, and I've got a few sets of bushings and rollpins, so once i locate a kinematic lever, I'll make a good box out of this one and use it to help some poor 964 soul in need when he inevitably breaks his rollpin.
The roll pin- just to drive it home- breaks in all of our cars because we don't have the clutch pedal stop on the floorboard set properly. If your clutch pedal travels too far, the piston in the clutch master hitting the back wall of the master is what stops the pedal travel. When this happens you are putting huge sheer force on the rollpin and it cracks and then breaks.
This is a particularly important point for all that have bought a Rennline alluminum floor board, because you have to swap all the parts from the oem floorboard to the alluminum one. And most people don't - in my experience. So- if you have no pedal stop, install one.
#52
Instructor
Nice work, Goughary! That pneumatic grinder definitely has more power than the little Dremel tool I attempted to grind down the welds with. I'm glad you were able to get it disassembled. Hopefully the pieces can be re-used in a future car. I'm happy with the 993 assembly I got from you! Once I get some more driving in on the new pedals I'll report back, but from my initial impressions last night around the block, the clutch action felt much lighter and smoother, which is a big bonus with an RS clutch and heavy pressure plate. Thanks again and nice work!
#53
Technical Guru
Rennlist Member
Rennlist Member
The roll pin- just to drive it home- breaks in all of our cars because we don't have the clutch pedal stop on the floorboard set properly. If your clutch pedal travels too far, the piston in the clutch master hitting the back wall of the master is what stops the pedal travel. When this happens you are putting huge sheer force on the rollpin and it cracks and then breaks.
Originally Posted by Goughary
i knew it would be fun, and i have an extra clutch pedal that needed a box...and i figured if i rebuild this box
#54
Race Car
I didn't swap the boost spring Jason...so many other projects for other guys have gotten in the way of doing much of anything but the necessities for my car...
What are the main differences btw the 964 turbo box and the 964 box? I wasn't aware they were swappable- but to be honest i have never looked into it. Didn't occur to me that Porsche used a different box for the turbo.
What are the main differences btw the 964 turbo box and the 964 box? I wasn't aware they were swappable- but to be honest i have never looked into it. Didn't occur to me that Porsche used a different box for the turbo.
#55
Rennlist Member
I'm going to change out my roll pin and Master Cylinder this weekend. Can anyone confirm that the pic up the top of this thread (post #11) shows the correct direction for driving the roll pin out?
#56
Race Car
LOL, it’s a roll pin, either direction unless there’s an obstruction that would prevent the pin from removal.
#57
Rennlist Member
Originally Posted by Jeff Curtis
LOL, it’s a roll pin, either direction unless there’s an obstruction that would prevent the pin from removal.
#59
Rennlist Member
In mid-1992 when Porsche installed the RS pressure plate in the regular 964, they also started using the pedal assembly from the 964 Turbo. And then Porsche went through 5 or 6 revisions of the 993 pedal assembly which had its own set of problems. The last revision cured most of them but still had issues.