Question on Replacement A frames/ Rubber Bushes

[911addict]

My garage has told me my front bushes are perished and need replacing. I am in the process of getting a second opinion before I authorise the work.
They have quoted me around £500 for new A-frames and fitting.
I came across 'polyurethane bushes' and asked whether these could simply replace the worn rubbers and save me money? He said that to do this the A-frames have to be removed and sent away. Furthermore he says that these Poly bushes squeak after a while and are therefore no good.
Is this info correct?

 

[Nick Moss]

I fit Superpro poly bushes to all the cars that I restore. They are easy to fit and do not squeek, although the American Weltmeister bushes have been known to squeek.

 

[911addict]

Nick,
Are they simply fitted in situ? And how much would it cost?

 

[Nick Moss]

You need to remove the A frames, cut off the old bushes (a messy job) slide on the new bushes and refit. You will need to check and adjust the front ride height (5 minutes). The bushes are £42.60 a set and I would say there is about 4 hours labour. You may want to replace the ball joints and track rod ends at the same time if the car has done a few miles.

 

[Dave Wilkinson]

Mark,

There has been a lot of debate on this issue and the answer will depend on how much of the work you can do yourself and how much labour you land up having to pay for.

The 964 wishbones are supplied by Porsche with the bushes in place. They do this because the OEM bushes have voids moulded into them to create some compliance and it is important that the voids are correctly aligned with the axis of the mounting. The Powerflex bushes do not have the voids and are, consequently, a little harder. There have been rumours of the Powerflex bushes causing squeaking if they are not lubricated correctly on installation.

If you are paying your garage to do the work the additional labour involved in removing and replacing the bushes almost defeats the saving against replacing the wishbones complete. Many independents seem to shy away from doing it because the bushes are such a pain to remove and replace. Almost everybody who sings the praises of the Powerflex bushes are those who have done the work themselves and, done properly, they seem to be as good, if not better, than OEM. You pays your money and takes your choice!!!

Regards

Dave

 

[911addict]

Dave, thanks.

I have just spoken to Nick above and they don't do the Poly bushes for the 965. Does anyone else?

I have a local garage who have offered to do the job for me providing I source the bushes. They are enthusiasts rather than specialists and are fairly confident they can fit the bushes (as they have done so on other Porsche models). This will work out around half the price of the original quote for full replacement so I am quite interested.

As my original (specialist) garage told me my geometry setup is good, it shouldn't need redoing...or should it? Is there anything else I need to watch out for?

 

[Dave Wilkinson]

Mark,

Assuming Nick was talking about pre-964 911s, the suspension is very different on the 964. Powerflex have produced a bushing set for the 964 and I'm assuming that the Turbo uses the same bushes although I may be wrong. There was a special deal set up regarding the supply of Powerflex bushes and I believe they are only available through Milford Microsystems (01865 331 552) who will, undoubtedly, tell you more. The details are on the Powerflex web site here http://www.powerflex.co.uk/products.asp?cat=0025&catalog=0125&submit1.x=16&submit1.y=17&submit1=GO

I believe you WILL need an alignment check after fitting the new bushes since the effects of the worn bushes will no longer maintain the settings with new bushes fitted.

Regards

Dave

 

[Nick Moss]

Assuming Nick was talking about pre-964 911s

Errr. I engaged brain after posting! My comments do refer to pre 89 cars which don't of course have any similarity to 964s in the front suspension department [&o]

 

[911addict]

After all this discussion and more behind the scenes, I think in the interest of 'completeness of the job' I will stick with my mechanics recommendation. He's using the RS version which he reckons is better than original turbo. Ultimately, I think I'd prefer the whole unit replacement rather than the bushes.

 

[nathan 1981 930 G50]

Nick, how much stiffer/harder is the material than the rubber they replace approx ?

 

[Nick Moss]

The Superpro bushes are slightly harder than standard rubber, but do not give harsh ride. Their biggest benefit is their ease of fitment, and in the case of the front A arm and rear spring plate bushes is their saving over the standard rubber replacement which entail replacement of the enture arm or spring plate as the rubber is vulcanised to the steel and not available seperately.

 

[nathan 1981 930 G50]

Thanks for your reply.

Could you say in a percentage how harder ?
I was interested in the trans/eng mounts at the moment.

 

[Nick Moss]

Could you say in a percentage how harder ?

Errrmm... No, not exactly.

 

[nathan 1981 930 G50]

Bah.

One of the things I notice is that as the car warms up so must the rubber mounts, as I can feel them getting more movement as they soften.

Maybe I am imagining this.

Any idea how heat affects that material ?