About 2 years ago I invented the process where we could rebuild the early 928 upper arms in the car and replace the ball joint cups. The early arms were cast, and designed to be serviced. The ball joint comes out with a circlip, and the new one goes in.

If your upper A Arm is too worn to rebuild in-car with our kit, 928 International supplys professionally rebuilt ones. You remove your A Arm from the vehicle to exchange with the new one.

But, Porsche changed from cast to forged upper A Arms in late ’86 – and the new upper arms were not designed to be serviceable. Milling out the ball joint socket to press in a new steel ball joint has been attampted, but there is not enough material around the ball joint o do this safely.

The upper a-arm with ball joint is still available (for the moment) from Porsche and the suggested retail price on that is $926.00 EACH. You need two.

All you have been able to do (until now) is go to a junkyard and hope to find an upper a-arm with fewer miles than yours and swap them out.

But – I have been working towards a new manufactured part for this. Photos attached. We went to the race fabricators, and have a welded steel a-arm of the exact dimensions of the Porsche arm, with a high-grade spherical ball joint in it. This is a bolt-in piece that requires no modification to your 928, and it is serviceable if need be at any time in the future.

Our part features a steel crossbar, oil-impregnated bronze bushings, and zirk fittings so - for the first time ever - the upper a-arm bushings are greaseable. These will be even tighter than astock a-arm with poly bushings, yet rotate with less effort on the spindle.

For you racers, the stock upper A-Arm with ball joint weighs 5.5 pounds and our upper A-arm with ball joint weighs 4.0 pounds.

We are starting on-car testing now. I'll let you know how it goes.

 

wow, thats nice!

 

NICE!!!

So what MYs is this planned for?

Also, I see the top of the ball joint has a nut for removal, does the ball joint have flats on it to take it out?

And do you have a target price?

 

Carl,

Beautiful work. At this time, any idea of what the cost will be?

 

Let me know the price ASAP - I've been looking around for a set of upper S4 control arms for my 79 track car. This looks like the ticket for my project.

Good work as usual Carl!!

 

I have been working on and off on a cad drawing of these arms for a while, and was always concerned about the strength at the welds, which there were no joints on any of the upper arms, early or late. Luckily we know most of the stress goes onto the lower arms which are quite robust.

The top just follows the hub up and down, but takes stress under turns in the "Pulling out" from the car direction. How long does the bronze last on your arms - I guess you will be find out since you will put these on your race car to get better camber right?

And again, any idea of cost?

 

Are these for racing applications only? Are there any plans to make the joint water/dust proof or is this jsut a prototye?

 

Carl for yet another modernised 928 component!!

 

It'll be interesting to hear pricing information. But I'll tip my hat to Carl for working on a needed solution, just hope it's an affordable solution. Good job.

 

Answers to some questions:

These are designed to fit late-86 and up Porsche 928 all.

These are suitable for street or race driving. Designed originally for street use, the fact that they came in lighter than the OEM a-arm is just luck. Street use - where suspension components is concerned, is often tougher than race use. Streets have potholes, sink holes, curbs and junk.
Race tracks do not. That's why a F1 car can ruin a spindle and front end on the rumble strips for chrissake - things that the typical street car would laugh at and keep going. These are designed with the strength needed for street.

We are testing them now on-car to make sure they clear the late model air pressure sensors and a few other things.

I figure they will come to market in about 1 month or a little more, and they will retail for $249.00 ea.
and come with the ball joint included.

If you need upper a-arms for your 1986 or older 928, there are two solutions already available: rebuild them on the car with our ball joint repair kit, or replace them with a rebuilt arm from 928 Intl.

Its the 86.5 and up owners that were without options.

How does $249 sound?

 

$249 sounds a WHOLE lot better than $900+! Super job!

 

Some may not know that tracked 928's have been known to use late upper arms with early lower arms for increased negative camber.

Reason why I want a set of these for my 79

 

I'd say keeping it to 450 for the pair would make them go quickly for those who know what a worn upper ball joint feels like. If you could market the idea that many people have very high mileage S4 928s with little or no knowledge of what the condition is of thier upper a arm, you could do well depending on your margin.

 

Wasn't there a fellow that had new upper arms made for his S4 which allowed him to correctly fit 911 offset wheels to his car? At least I think that's what I remember. I wonder if his version also allowed the rebuild of the ball joint cups.

Carl, you need to change your company name to "928 Innovations". Great job!!

Regards,
Roger 87s4

 

True - very true. Good point.