FredR

I am contemplating a major suspension revamp and it would seem that for the later type upper A arm there is no repair kit available for the ball joint for some reason and yet some outfits can refurbish these things.

The methodology logically has to be the same as with earlier arms, an insert with the ball, socket, cover & spring so what is the mystery element here?

Has any one opened up the later joint or better still got any pictures of such?

Rgds

Fred

ammonman

I think the biggest difference is the later joints were topped by stamping an aluminum lip down over the joint cover plate to secure the joint into the arm and make it water tight. The plate on the early joints was retained by a circlip and then covered with epoxy. Once you remove the stamped metal that retains the plate on the later joint there is no way to hold it in place and seal it once the joint internals are renewed. Hence the rebuild process for the later joint requires insertion of a cartridge style ball joint either screwed or pressed into place.

Mike

FredR

Mike,

I suspect you are on the money here. I work on the principle that if someone can make it and someone else can refurbish it then it should be possible to rebuild it even if not quite the same it was originally. The notion of having to replace a complete arm for a component of relatively low price failing is outrageous. One should be able to purchase a ball joint and a couple of bushes for little more than $100 or so per side.

The earlier arms that are rebuildable [in-situ] do not take appreciably higher loads than the later models and I have not seen those things reported as failing en-masse.

Rgds

Fred

ammonman

I ended up putting a set of rebuilt units from 928 Intl. when mine needed renewed. Their rebuilt units have an insert type ball joint. I don't remember if it appeared to be screwed in or pressed in. The rubber bushes were re-cast with entirely new rubber rather than just inserts.

Mike

GregBBRD

Fred:

By the time the ball joints are worn out, the rubber bushings on the inboard side are also at the end of their life.

Buy a set of rebuilt control arms from 928 International.

Absolutely amazing!

FredR

Greg,

I have no doubts about the quality of the rebuilt arms but given my location sending cores back costs about as much as the core charge and it irks me that I have perfectly good base components that cannot be reworked for what is probably a $2 seat insert set in the ball joint given the ***** themselves seldom if ever wear out.

Fully agree with you about the rubbers at the pivot point and everywhere else for that matter. My suspicion about the annoying squeak I have posted previously about is [I now suspect] most likely coming from those rubbers on the upper arm given I have more or less eliminated everything else. I recently pulled a lower A arm out for inspection and that was falling to pieces on the open stub end so I figured it is about time to go through the job lot if I can obtain budget permission from the "Trouble and Strife" [wife].

On the one hand one does not want to try anything on the suspension that has potential to fail but on the other refurbishing a simple ball joint should not be like hitting a "Brick wall" as it were. The lower ball joint takes much more of the load [I suspect] and that is an easy to replace bolt on affair.

Rgds

Fred

FredR

"Final call" for input as to how the later UCA ball joint is assembled on these things.

Rgds

Fred

Lizard928

They are as Mike says.
928 intl rebuilds are the way to go!

FredR

Colin,

Any idea if they are screwed in, pressed in or any other "in" for that matter? Mike was unsure of such.

Getting the old one out will be much easier if one knows how they are fitted in the first place.

Why they changed the original concept is somewhat baffling- perhaps it was to miff owners like myself!

Rgds

Fred

hacker-pschorr

80/20

20% chance the updated design is stronger. This doesn't mean the old is weak, Germans engineers go out of their way for a 1% increase in strength.
80% chance it was cheaper to manufacture this way.....

I know what you are trying to accomplish, but replacing upper arms vs just the joint is commonplace around the automotive industry. Do a search for upper ball joints for any random car you will see a lot of upper control arm "kits" which are preferred over doing just the joint.

GregBBRD

The ball joint on the rebuilt 928 International "A" arms in not an "inserted" ball joint.

The rebuilder uses individual pieces (ball socket and plastic pieces) with a threaded cover (instead of the pressed in and glued original cover) that makes it appear that the entire ball joint has been replaced.

FredR

The "doing it cheaper" bit might make some sense. As to knowing what I have in mind is impressive given I have not told anyone [yet]- on the other hand psychic ability is probably a great asset for an astute moderator like your goodself.

I did some research into this and found that the early 928's, the 944's and some BMW's seem to have joints that are capable of being refurbed quite easily -indeed not sure I have heard of any car that has to replace the entire upper arm as Herr Ferdinand seems to expect. But then I have only seen the arms on cars that I own or have owned and that is not too many.

At the moment it seems as though I may have to find a s/h passenger side arm to tidy me over and then play around with my current one to evaluate how it was constructed in the first place.

Rgds

Fred

FredR

Bingo- thanks for that Greg.

I was talking to my friendly machine shop boss the other day about whether he could thread the top section of the arm so that we could insert a retaining disc and he opined it was no problem for his chaps to do this- my assumption being that a threaded section of 6mm depth might do the trick and still allow sufficent depth to pack the joint as needed.

Given that the shock absorber and the lower arm take the vertical shock loading, the top joint for the most part stabilises the plot presumably restraining sideways thrust during cornering and braking. Thus the ball sits in a phospher bronze type bearing material on the joint side and probably something like PTFE on the top compressed by a spring that allows slight axial movement but nothing more.

When I had my joint apart a few weeks ago I was sure I could feel a slight axial movement but no lateral movement. My assumption was that the joint is shot but maybe I am being a bit conservative. For sure I could not feel any rock in the joint with the wheel mounted but off the ground. The upper arm still resisted movement but I could move it up and down by hand with quite a push as it were.

My presumption is that given the state of the lower arm rubber the rest must be close or not far behind in terms of degradation. Nowadays better materals are available for the bushes- whether they need such is a different matter but the heat here really does kill rubber prematurely.

For the joint itself whether materials for the refurbishment of the joint can be located is another matter- clearly they are available.

Rgds

Fred

ammonman

Thanks for clarifying the construction of the 928 Intl rebuilt arms Greg. That is an ingenious solution. With my assumption that the joint was an insert I always wondered how they could machine out the old joint to make way for the insert and not compromise the strength of the arm end.

Mike

hwyrnr

I might be off in left field, but why have it machined for threads instead of a groove for a circlip?

James