Ball Joint rebuild kits form RennBay
#1
Rennlist Member
Thread Starter
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
#2
Nordschleife Master
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Nope. But I did the ball joints on my 944 with one of their kits and was quite pleased. Not hard to do. The 928 upper arm balljoint looks to have the same basic construction as the 944 lower balljoint. It took about 1 hour working time for the pair. The trick is to get the earless snap ring out. After that it's pretty easy.
This repair should be doable with the arms on the car.
I'm surprised that someone hasn't jumped in yet on the safety of it. You've got to check out the sockets for cracks and wear. The kit comes with new metal upper (towards ground) bushing which will strengthen the balljoint. It doesn't take much force compared to the lower.
One thing I don't like is the price. For $220 there should be new ball studs and springs in there. Their 944 race kit has all of that and comparable bushings and is $185.
This repair should be doable with the arms on the car.
I'm surprised that someone hasn't jumped in yet on the safety of it. You've got to check out the sockets for cracks and wear. The kit comes with new metal upper (towards ground) bushing which will strengthen the balljoint. It doesn't take much force compared to the lower.
One thing I don't like is the price. For $220 there should be new ball studs and springs in there. Their 944 race kit has all of that and comparable bushings and is $185.
#5
Developer
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
It is the same kit. We co-developed the kit with Travis at Rennbay. Our idea, design by both of us, thieir manufacturing, our assembly instructions.
The 928 Upper ball joint is not the same as the 944 lower BJ - although it may look it from the outside.
Please read this post:
https://rennlist.com/forums/928-forum/212787-new-product-ball-joint-rebuild-kit.html
The 928 Upper ball joint is not the same as the 944 lower BJ - although it may look it from the outside.
Please read this post:
https://rennlist.com/forums/928-forum/212787-new-product-ball-joint-rebuild-kit.html
#7
Developer
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
"why not for the late model cars?"
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) ;-)