Jump to content

Problems with aftermarket Coffin arms


Recommended Posts

This time last year I had my 2 rear Coffin arms replaced by a local Indy (shall remain nameless for now). It appears they replaced them with the cheapest they could find, to be fair and being a bit green on Porsche parts and knowing there were specialist I went along with it. A few months back I noticed a creaking noise and the occasional knock so the car went to another suspension specialist to be checked over and below were their comments on what they found, they also replaced with Meyle parts and now is all good.. 


Regards the rear bushes/arms...

They were clearly aftermarket arms, as they had no OEM part number, but we don't know what brand they were as they had no markings. The issue with these arms, was that the length of the bushes were shorter than the OEM bushes. Due to the boxster/cayman having a steel strengthening brace supporting the cross member, there is no 'give' in the aperture which clamps that inner bush. The camber eccentric bolt was torqued to spec, and although this held the part in terms of its geometry, the bush was able to move fore-aft in the cross member, causing the creak. The creak was a constant noise, even on the best of roads, but if the wheel hit pothole/drain cover etc, or there was a large displacement of the suspension, the bush would then 'knock'. 

We were able to very easily replicate both noises on our in-ground damper tester, and naturally once the arms had been replaced, the noises had gone.


We have seen similar issues before with aftermarket arms when fitted to boxsters/caymans. When these arms are fitted to 996/997, the issue is not apparent, as the 911 does not use a steel brace, and the 911 aluminium cross member can yield enough to clamp the slightly smaller bushes used on these arms. Likelihood is the parts were tried/tested on a 996, and presumed that they would fit all models.

Link to comment
Share on other sites

That’s very poor (service). 


I had Meyle coffin arms fitted by RPM a couple of weeks ago - no creaking / knocking noises. 


I supplied the arms myself, bought from frazerparts.co.uk - 987 gen 2 arms, £265 (inc VAT) for the pair.  They came sealed in a MEYLE bag, in a MEYLE box with part no.s on them that corresponded with the Meyle website part numbers. 


Desgn 911 sell them too, but at about £280 + VAT!


hope you get some compensation from the original garage. 

Link to comment
Share on other sites

I can’t quite work Porsche prices out. Some bits a downright reasonable and others scary. For instance my front side fairing/skirt thing that goes under the bumper was £45 ish ready in primer. That’s pretty good I thought. Then a replacement locking wheel nut -£8. Eight pounds!! You couldn’t get one at Halfords for that. Then there’s mechanical items that I dare not even look at. Steering rack I think was £1600 from Porsche. I bet all the small non mechanical bits are dead cheap and the bigger mechanical bits or body panels scary prices.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...

Important Information

By using this site, you agree to our Terms of Use We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.