ROG100

The Release Bearing for the 78 to 86 double clutch is NLA.
I have sourced the bearing no problem.
The next task is to have the center tube, that is located - swaged end - into the bearing ID, machined.

A question for the "928 Brains" please? As you know I am "manual" challenged.

1) What is the significance of the slotted hole (see picture) on the side of the RB center tube? This is an extra machining op and if it is not need I will leave it out.

I am also looking for 78 to 86 RB cores for the initial production run.
$30 for the core providing the body is in good shape and only the bearing is toast.

Mark Anderson

The slot is for the tooth on the washer to fit into.

Rob Edwards

There's a little protruding nub on one of the contoured washers that assembles with the TOB and PP, I guess to keep it from rotating on the PP fingers. It's not listed separately in PET.

Here's a pic:

Mrmerlin

The slot is necessary so the bearing will turn with the engine,
the hardened disc with the nub is all that keeps the disc spinning with the PP fingers.
Remember that the TOB is spinning at engine speed all the time, so a hi speed, sealed bearing with a high heat range is required

ROG100

You are all awesome - what a great community and wealth of knowledge.
Ok Ok it stays if it has a purpose 8>)

I have chosen a SKF RS1 bearing which is far better quality than the NTN bearing used in the original RB.
I specified the application to the bearing gods.

Benton

Great work, Roger--nice of you to step up to the plate and hopefully rectify this issue.

hacker-pschorr

I broke the little nub off that washer a few years ago. My clutch randomly disengaged.

https://rennlist.com/forums/3145762-post132.html

At least four threads and a few hundreds posts and a ton of $$$ tossed at this problem before the real culprit was discovered.

So in other words, it's a very important slotted hole

dprantl

Also, that tooth on the washer wears out over time. When I was replacing the clutch on my former '86, the tooth was almost completely gone. So, not only do we need a new bearing, but we also need that washer and retaining ring. The ring I noticed was very worn as well, much thinner than new. Oh, and the washer is quite brittle and also pretty easy to break when installing, don't ask me how I know

Dan
'91 928GT S/C 475hp/460lb.ft

kccampro

Score! I have 3 of them in the shed... time to start digging.

hacker-pschorr

+1

I think I know where a stash of them is hiding somewhere in Green Bay.

Rob Edwards

RE: the toothed washer, I have a new one sitting at home, if there's anyone that can borrow it to take measurements and get new ones made, I'd be happy to mail it out.