Ball Pivot for Clutch Fork

[RWebb]

Can the 1969 style ball pivots (ball shaped head on the stud) be "upgraded" to the square headed style used in the 1970-71 transmissions?

[Scott Clarke]

No, because the pivoting surface faces different directions on the two. The '69 pivot works in compression, and the '70-'71 in tension.

[mjshira]

you need to get the improved ball that is stronger. been awhile since I had a 901 trans but do a search here. you can also check with the 901shop.com if Wayne doesn't have the part. But DO NOT reinstall this part with an OEM ball, get the stronger one, you'll be glad you did.

[RWebb]

Thanks - Grady had once said something about using the newer part, but I think he thought I had a normal '71 setup on my transmission.

As it turns out the pdf PETs do not go back before 1970 so there is no diagram there. The standalone version has an INCORRECT diagram for the 1969 and earlier cars! The ball pivot is not shown.

Luckily, Stoddard's has a diagram on their web site:
http://www.*************/shop/shopdisplayproducts.asp?id=181&cat=Clutch+Release+Components+

They show p/n 901-116-771-01 for the ball pivot ($29.xx). But it is not clear if that is the improved one or not. From your previous posts, James, it looks like the new, improved one is not a stock part, but is after-market only.

If, I have the part in hand, how would I recognize the improved one?

[RWebb]

And, BTW - does anyone know exactly what socket will get the damn thing out of there? I did it before but can't remember what I used - think I might have borrowed a tool - maybe a long 14 mm Snap-On 1/4" drive socket (not 3/8" drive, that does not work).

The problem is that a socket that fits around the hex at the base of the ball and its little stem won't go down in the very very small clearance where the housing is ground away for the ball to fit in. It requires a 14 mm socket - something I only have in 3/8" drive and the wall of the socket is too fat.
Also, the ball has to be able to fit down into the socket 'tube.'

[mjshira]

I would call the guys at 901shop.com. They race cars with this gear box, they should know. You can also call Pelican to make sure they don't have the part. I last purchased one in 1998 and I went through Zims in Dallas.

[RWebb]

Thanks - I have been running searches for a while & found yours with Zims mentioned.

I've sent Emails to Patrick Motorsports and to 901shop.

I'm now trying to figure out how to get the ball stud itself out...

[mjshira]

Patrick should be able to help you with that. They really know what they are talking about.

[cnielsen]

Damn, I hated those pivot bolts. Before I upgraded to a 915, I replaced it about 3 times...each time getting a little more frequent. I got thinking... I wonder if my T/O fork was worn and if that could have led to the premature failure of the pibot bolt.

Just a thought, and glad I upgraded to a 915.

[mjshira]

if the clutch is not set up right when installed, even a bit off, you can break this part sooner than if set up correctly. the new part is made of ti I think and that is why it is so much stronger.

[RWebb]

I replaced the nylon cup in the fork not long ago so I don't think there is excessive wear. The real issue here is an improperly done conversion flywheel. The machinist who supposedly set everything up right to use a 911 trans. with a 3.2L motor screwed it up and has now left me hanging. A friend tells me that if I can get a washer under the pivot to relocate the ball (the fulcrum) further forward, then I just may be able to get the Rube Goldberg device to work.

Anyway, here is what I am up against in terms of getting the ball out...

[Grady Clay]

Guys,

The clutch pivot for 901, 911 and 914 has two distinct versions and two versions of each.

The four are:
901:
The press in type from the very early 901 and immediately updated by Porsche.
The screw-in type ball (as Randy has modified his type 911 with) was the replacement and is common to all push-type clutches for 911, 912 and 914.

911:
These are the unique 911 ’70-’71 push-type clutches.
The ‘early’ version has a 6 mm stud with a 10 mm wrench size nut. This failed every time.
The ‘replacement’ pivot has a 13 mm wrenching hex integral to the pivot (no nut).

I have previously posted about all of these with Factory diagrams and my photos.

The very early 901 (’64-’65) press-in version should always be replaced with the threaded version.

The early 911 version should always be replaced with its later version.

Probably most important to note is the difference in the pivot location.
Randy’s image above shows this clearly.
The plug is where his ’70-’71 pivot was originally located.


Tomorrow I’ll post an image of my ‘special’ 14 mm socket (modified deep 12-point Craftsman) for the 901 ball pivot. More fodder for a 901 chapter.

Best,
Grady

[RWebb]

Ha!

A friend ground down an old black oxide 14 mm socket he had - ground the tip down to get rid of the internal chamfer, then ground the outside to reduce the wall thickness...




It worked perfectly. Here is the ball pivot removed. There was not a washer underneath.

[RWebb]

- Zims knows nothing about a new, improved ball pivot. He also said that the only time they fail is if someone has ground the flywheel or used the wrong pressure plate (such as one with extra clamping force). The do not stock the OEM part either (nor does Pelican apparently).

- 901shop also did not know of an improved ball pivot (he said there used to be an "upgrade" kit for the 911 trans. item [that one has the hex bolt feature on top of the stud, used in 1970-71] but had never heard of an after-market part for the 1965-69 transmissions. He was a nice guy tho and offered to send me a couple of good old stock ones for cheap.

- Patrick does not offer any improved version. They think they may have done so in the past.

[Scott Clarke]

According to Grady (above) you already have the improved type. The early one was pressed in place, and the replacement threads in, like the one you have.

[john walker's workshop]

i have a used original in good shape. the reason they snap is because the fork has limited travel to pivot in each direction and when it reaches the end of it's travel and still needs to go further in order to work the clutch, it just prys on the pivot bolt and eventually pops the end off. this is because of the flywheel being machined deeper and/or improper stacking of the pivot, leaf spring/washer under it. an extra washer is used when the flywheel is machined, in an attempt to keep the original operating goemetry.

[RWebb]

I ordered a new one and will put that in. There is a tad of spalling on the ball in one spot and I am concerned about the angle the threaded stud sits at in the pic above.

Scott, the rumor was that there was an _after-market_ version, perhaps made of Ti. That would be different from the stock item Grady describes. It now appears that there is no such animal, and maybe never was.

[Scott Clarke]

Randy-
I think you are thinking of the chromoly one Weltmeister makes for the '70-'71 setup.

[RWebb]

Thx Scott & John. I have a new one on order.

It wasn't me -- it is a bunch of old posts that most likely confused the 1965-69 ball pivot with the 1970-71 item.

BTW, in the pic above, note that on mine, the threaded stem appears to be slightly bent...

[Scott Clarke]

I did notice that. Due to your flywheel trouble. you were operating it at the most extreme possible angle. As John points out, that is when they bend.