Carl Fausett

Application : Porsche 928 1978-early 86

Because the upper A-Arm in a 928 is so hard to remove, we set out to develop a method to rebuild/replace the upper ball joint while still mounted in the car.

I had the good fortune of finding Travis at Rennbay, who has had success rebuilding 944 lower ball joints, and I got him on my team to see if we could develop an upper ball joint kit that could be installed without removing the suspension from the car. 928 International rounded out our team, (thanks, Mark) and kept us supplied with early and late-model upper a-arms which we destroyed in the process of inventing this kit.

Now it is ready for you, complete with downloadable installation instructions.
See them here: http://www.928motorsports.com/install.html

Background: The Upper A-Arm on the early 928s are cast aluminum, and designed to allow the upper ball-joint to be serviced. There is a snap-ring holding in the old ball joint, you remove it and install the new ball joint. This kit and instructions allow you to do this with the suspension still IN THE CAR and also replace the all-important ball joint bushing.

Quality Parts: Our ball cup bushing is machined from a single piece of aluminized bronze, the preferred material for toughness and long wear. Look at the photos below - you'll see what a cast ball joint cup looks like and how they fail. They shatter. Our ball joint cup never will! New polyurethane ball joint grease boots are also provided - everything you need!

Ease of Installation: The Ball Joint can be serviced with ordinary handtools. Not only do you not have to remove the upper A-Arm, but when you do it this way, the car will also not need an alignment when you are done. Saves Time AND Money!

Rennlist Special Although listed at $219 on our site (enough to do both L and R Upper ball joints on your car) I am offering you Rennlisters as special at $195.00 per kit. Mention this thread to get that price when you order.

Available thru: 928 Motorsports, and 928 International.

Let's hear what you think!

Carl Fausett

Here you go:

UKKid35

Please don't stop your R&D work, it's very impressive! Even though this particular development is not relevant to my car it's very encouraging to see what you are doing.

SharkSkin

Very nice Carl! I don't need these either... yet... but ultimately I will. Thank you for your ongoing development efforts!

CWO4Mann

This is excellent work! Thank you very much for the effort. I am sure my 928 will need replacements. When I get under it in the next few weeks I will let you know. I am working on it from rear to front, interior and body first (the "easy" stuff).

Cheers,

Dave

Garth S

Complete, even to the grease nipple on top!

Slightly related - is it equally feasible to rebuild the lower steel ball joints - for either the early cars or the S4 type? .... or just cheaper to toss and replace?

Scott M.

Carl;

How does the 928 kit differ from the 944 kit Travis has been selling for lower A arms on 944's??

Scott

T_MaX

U da man!

G Man

Very nice. I will definantly be using this method when the time comes!

BC

I thought it would be that easy. I have two arms (early) that I was going to try to take apart.

Okay, on to the S4 arms that are fully sealed!

borland

Nice kit! But why does the design include the grease fitting? The original was sealed.

Is the new cup softer than the original, thus more wear products and need for regreasing?

What's different about the later (>late 86) cars? Or is another kit in the works for them?

borland
90' S4

karl ruiter

Cool, I am so glad you are doing this stuff, and I will certainly be using this kit as I think my cab will need attention up there pretty soon. I wonder if you could re-use some of these parts to make a lifetime shifter front ball cup. They are such a PITA to replace and if you have your 928 a long time you are looking at doing it more than once.

Carl Fausett

I'll answer both questions:

The "why add a zerk fitting" question:
putting a zerk fitting on the top is just the responsible thing to do. Where the manufacturer only needed this part to last thru the warranty period of the car, we feel that some 928 owners have a longer duty cycle in mind than that.

Without a zerk fitting, it is not possible to force a little new grease into the joint -which forces out the old grease that has dirt and water in it. The old way - with no zerk fitting - when the rubber boot cracks or gets loose and moisture/dirt/grit gets in there, there is no way to force the bad grease out and flush in clean new grease.

Bottom line: equipped with a zerk fitting, you stand a chance (if you use it) of making your ball joint last much longer than OEM.

The 86.5 and up upper A-Arm question:
many of you know that the early upper a-arms were cast, and in 86.5 they went to a forged upper a-arm.

...but that is not the only change they made. The early (cast) a-arm has a machined groove for a circlip (the ball joint was engineered to be serviceable); and the later (forged) a-arm has no such thing. To hold in the ball joint, they peened over the aluminum to hold the ball joint in place. This is not servicable.

With cores provided by 928 International, we have tried to unfold the roll-over, service the ball joint and then fold it back... but of course, since it is forged the aluminum cracks and this does not work. Then we also tired machining off the peened collar and cutting in a circlip groove so we could rebuild them with the same early ball joint kit. It worked, but its nasty. Not easily done. Now we are looking into a new cast meta-metal part instead.

Travis (on our design team for this project from Rennbay) has a Meta-metal manufacturing setup he wants to apply the late-model 928 upper a-arm too. If it works, we can reproduce the upper a-arms with designed-in ball joint serviceability.

So, on the late model cars, we have so far gone from a: "replace the ball joint in the car" (which was our first choice) to a "you are going to have to remove the a-arm and send it in to be rebuilt professionally" ; and now to our 3rd design position "we are going to cast a new, serviceable upper a-arm".

That's where it stands at the moment.

I learned of this problem from 928 International about 6 months ago and started working on it then. I was shocked to discover yet another end-of-life item for our fine vehicles.

For you late-model guys, when your upper ball-joint wears out (and it eventually will) - it is already discontinued by Porsche - the only option is to search the dismantlers (928 International) for a used upper a-arm that has better ball joints than yours.

What will we do as 928's in boneyards become more scarce? The price of an upper a-arm with good ball joints is going to go up and up - until they are all gone. That spells EOL for our car.

So, we put a little team together with Mark at 928 International and Travis at Rennbay to solve this problem - and keep our 928 on the road forever. (que Chariots of Fire theme music) ;-)

I suggest - if you have a 86.5 and up 928 and the idea of having an available replacement upper a-arm with new ball joints interest you, that you let your feelings be known on this thread (Travis is watching) so he can get a level of interest in this casting we want to do. The more people that are interested, the more practical the expense to us of making the molds and the development is.

Benton

Carl,
Awesome stuff. I'm sure I'll be buying a bunch more from you in the future (flywheel, clutch, ball joint kit) but I can't wait to try out my solid motor mounts for now. Keep up the awesome work, as I love seeing what you come up with next.

BC

Late Cars already need upper a-arm ball joints. Many many do. Especially with all the 125k plus 928S4s running around - there is already a market if the price is under a certain line.