Balljoints

[robdimond]

It's me again with another raft of technical questions...

My steering is still not quite right. I've replaced one of the track rods, a wheel bearing (both of which were on their way out with very noticeable play) which have both yielded improvements. The arb bushes were also completely shot and I have replaced.
Both of the struts could do with replacement (which is why I'm watching Dave's thread with interest). I also think the balljoints are on their way out... with water pump pliers I can get about 2mm of play 'squeeze' in each one...

I have a serviceable spare pair of control arms I bought a while back. They are perfectly usable but I thought I would tear one down just to take a look and possibly rebuild. The upper plastic bushing was very thin and split into two pieces. The aluminium socket does not appear to have any wear. What is the verdict on rebuilding these? The rennbay kit is highly rated in the US but there are others available. The rubber bushing is not available as a separate part from Porsche... is there a good source for these? Is it worth updating the castor mounts to 968 spec, even keeping the 16" wheels?

Is it possible to refurb the strut top mount?

My intent long-term is to replace everything, possibly the steering shaft as well, then get a full alignment done.

 

[IanK]

I don't think the ball joints in the wishbones on an S2 can be replaced - well not without specialist equipment anyway.

I just replaced one of mine with an exchange unit from Hartech at £175 + VAT.

You get the complete wishbone with a new ball joint and bushes for that.

Regards

Ian

 

[robdimond]

Hi Ian,

I had not realised that the Hartech ones were £175... £300 was the figure I had in my head (perhaps that was for the new ones from an OPC). Worth considering for peace of mind given the consequences of a failure at speed.

It's true the late wishbones are not meant to be DIY rebuildable... but kits are available and it has been done (there is a youtube video of installing the rennbay kit).

Rob

 

[Mikebarry202]

Just seen a sticky on these ballpoint repairs in the Technical Articles at the top of the page.

 

[pauljmcnulty]

ORIGINAL: Mikebarry202

Just seen a sticky on these ballpoint repairs in the Technical Articles at the top of the page.

Yep, but with the caveat that there have been significant number of DIY ball joint repairs fail.

If you are a skilled mechanic with all the right tools, then you're going to do as good a job as Hartech. Once you factor in the time fitting them yjough, and the cost of the geo afterwards, it's a risk if you aren't completely confident.

 

[Monkeythree]

I fitted balljoint kits from Design911 on mine Rob. I only actually used the steel ball/taper and the plastic parts from each kit as the metal parts looked pretty nasty and re-using the sturdy originals seemed the better option. Having seen the kit, I'm sure there must be another one with the same parts on the market for another car at a much lower price but I don't know how you would go about identifying it. Time will tell if the rebuild kit is robust or not.....

I fitted Powerflex poly bushes to the inners in place of the rubber originals. Takes about an hour to get the original one out and about 15 seconds to put the Powerflex one in.

I fitted 968 castor mounts at the back.

No idea how all of that feels on the car because I can't drive it until the summer!

Edited to add that I think I remember seeing on here that you can change the bearing in the top mount (but I suspect any play would be from the rubber part anyway)

 

[Paul190H]

I did my S2 ball joints with the Rennbay kit, takes a bit of time but well worth the effort and manageable by a competent enthusiast. I also went with the Powerflex bushes while I was in there.

 

[zcacogp]

This topic seems to come up fairly frequently on here, with people both for and against the Rennbay kit. I've dug up the Rennbay YouTube instructions and they make the job look pretty simple. It's here:

https://www.youtube.com/watch?v=PaVvsUY-Uhc

I can't see that job taking more than half an hour per side, and less once you know what you are doing. Of course, the process of getting the arms off the car will take a while, as will putting them back on. Having watched the video, I can also better understand the oft-cited problem with the bottom of the sockets wearing, and the need for the stronger brass cup to hold things in place.

ORIGINAL: pauljmcnulty
Yep, but with the caveat that there have been significant number of DIY ball joint repairs fail.

What is it about the repair that fails? They wear out prematurely, or something actually breaks?

Also, what's the best place to buy the Rennbay kit? Are they available from a UK supplier?


Oli.

 

[John Sims]

IIRC mine just fell apart. It was probably the retaining circlip giving way. I was being a little enthusiastic with the curbs at Bedford but was still rather disappointed. ....another upgrade that wasn't. I put the original wishbones back on.

 

[robdimond]

Thankyou for all the feedback...

The only failure I was aware of was (Peter Empson's?) track car where the pin sheared off the ball in the joint. It is the catastrophic failures such as this that concern me where the driver is left with no control of the vehicle.

The Rennbay kit is £125 and powerflex bushes cost £63.62 to do both control arms + £90 seems to be the going rate of a spare pair of control arms. That's probably only a tank of petrol difference from the Hartech arms after you've paid import duty, VAT and shipping on the Rennbay bits.

If you read here:
http://www.944turbo.org.uk/balljoints.shtml
it's pretty clear that the Hartech rebuild is completely different from the kits available... from what I understand they bore out the old joint and fit a brand new unit.

So for my money I'm inclined to sell the spare control arms I have (which are rebuildable by someone more intrepid) and get a pair of the Hartech rebuilt arms when I have the suspension in bits.