ShawTurnage1988

Currently in the process of ordering a new clutch kit. Should I go ahead and replace the master and slave while I'm at it? The guy I bought the car from cut a massive hole in the wheel well 😒 So going to have to replace that anyway. Your input and thread links have already helped tremendously. Any recommendations on what brand or color rear main seal to purchase as well?

hacker-pschorr

Who are you ordering the clutch kit from? I only ask because some sources understand the difference in years and which parts superseded what better than others.

That hole is to aid in replacing the master. Some feel cutting that hole is an acceptable short cut when doing the job. Since the hole is already there you will at least benefit from it.

ShawTurnage1988

https://928motorsports.com/parts/clutchkitgt1dual.php

This is the kit I have been looking at so far ^. Still shopping around, also looking at pelican and 928 international: http://shop.928intl.com/mobile/CLUTCH/products/114/13/0.

hacker-pschorr

I have no experience with the 928 Motorsports clutch kit, but it's a modified unit and unless you plan on adding some serious power to your car, the stock clutch is all you need.

More importantly though, that kit is for 80-84 clutches and as it shows in those photos, will not work with the rest of your parts if original. As I noted above, the 78-79 cars are unique. Every part is a little bit different and you cannot mix & match all of them.

Also, one of the key components which may need to be replaced is not part of that kit - the indeterminate disc.

We may be putting the cart before the horse, I would drop the clutch, lay out all the parts and see what is in there. Someone may have already updated to the latest parts at some point.

ShawTurnage1988

Ya I realized that after sending it. I found this website as well:
http://www.autohausaz.com/search/pro...riction%20Disc
Hopefully will have the car on the lift by the weekend to pull the clutch and see what is actually needed. Just shopping my options and taking in a worst case scenario of what will need to be replaced.

hacker-pschorr

Talk to Mark Anderson @ 928 International or Roger @ 928's R Us for original equipment parts like this.

Between the two of them is everything you need and all the knowledge of what fits what which can really come in handy with clutch projects.

There is a good possibility you will need some used parts to update your car to the latest parts. If memory serves, not everything is available new anymore.

ShawTurnage1988

Awesome thank you for the advice and help

ROG100

All the parts for the double clutch are available and in stock.
However the intermediate plate is expensive.

hacker-pschorr

Is the original 78/79 clutch fork compatible with the current release bearing?

I've always wondered what difference the leverage was with the larger ball and updated fork compared to the original.

That's why I stalled working on my 78 since I needed a fork, larger ball which also requires upgrading the bellhousing.

Carl Fausett

ShawTurnage and Hacker: we do not offer clutches for the 1978/79 models.

Little piece of 928 history: after the brand new Porsche 928 was let out to car magazine editors and later, to the first 928 buyers; the first feedback started to come in. Great car, but the brakes were undersized and the clutch was too weak. Porsche "fixed" both of these early model issues by 1980 and 1981.

I wouldn't put any money into a 78/79 concentric clutch.

By 1980, Porsche had scraped the concentric clutch in favor of a pinned clutch that the used for 1980 to 1986 without problems. It shifts better, and is less likely to slip than the concentric clutch was.

To upgrade your 78/79 to a 1980-1986 pinned clutch you will need a used flywheel, a shifter release fork, a throw-out bearing (which you likely need anyway) and of course, all the regular clutch bits like the pressure plate and friction disks that you would be replacing anyway. The intermediate plate needs to be swapped too.

At the price and scarcity of concentric clutch parts anymore, updating the clutch to the improved design makes more sense now than ever before.

Carl Fausett

PS: when upgrading to the pinned-style dual disk clutch, the master and slave cylinders stay the same.

hacker-pschorr

I forgot about the flywheel.

As I posted above from the WSM, the upper bell-housing needs to be replaced too.

So basically, to convert a 78/79 to the later style double disc clutch, you replace everything from the crank to the torque tube, except the clutch shaft, lower bell-housing, and slave.

Further reinforcing my idea to convert my 79 track car to single disc.

GlenL

I'm not reading that. Is the hole too small for a later arm? Could that be hogged out?

So we got from "clutch not opening" to "replace it all."

I suggest getting a good bleed on the clutch hydraulics and cranking back the adjusters before committing to a replacement. The bottom cover will come off for the adjustment so you'll be able to check for problems.

Guy

you can upgrade the bellhousing with out replacing the whole unit. Stud is removed, threaded insert is used along with the updated ball. WSM has the details. I did it on my 79

hacker-pschorr

Maybe?
I don't remember why, but when I sat down with Jean-Louis and a pile of parts, I ended up leaving with a later style bell-housing. Maybe because removing it is necessary either way, it's a very inexpensive part - just put the newer one on was my decision. If a replacement bell-housing was $1,000 that would have swayed things.
Kind of a moot point when discussing a part most throw away when parting out a car. Just good to know the change is there.

Just a dialog discussing what-if's.
For a complete newbie like the OP, it's good to know that at some point down the road that clutch is 100% NLA (assuming it's still original) and good for anyone searching on the subject.

I don't see the harm in working through this problem in an open discussion.