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Which lower shock absorber bushes for bilstein shocks?
Posted: Fri Jun 19, 2020 7:12 am
by alanjf
I am refitting the bilstein shocks to my ‘69 911 having switched from the incorrect aluminium arms to steel. Thanks to help from members of DDK I have worked out that the correct shocks were the Boge. I would prefer to use the Bilsteins which were already on the car and are in good condition, but cannot find the right rubber bushes. Any suggestions?
If it helps dimensions:
Bilstein:
Inner diameter: 32mm
Length: 30mm
Metal bush to go inside the rubber bush:
External diameter:18mm
Length: 32mm
Thanks
Alan
Re: Which lower shock absorber bushes for bilstein shocks?
Posted: Fri Jun 19, 2020 7:37 am
by Gary71
Hi, it’s worth contacting Bilstein UK as they can supply the bushes separately. I did this when I went the other way from steel to ali arms.
However I guess what you are after is an early bush (12mm bolt) in later (14mm bolt) damper, which isn’t standard.
It maybe easier to leave the bushes as they are (as they are bonded to the damper) and get a sleeve turned up (or if you are lucky some 12mm. id 1mm wall tube) to step up the bolt diameter.
Re: Which lower shock absorber bushes for bilstein shocks?
Posted: Fri Jun 19, 2020 7:46 am
by Gary71
I forgot to say, the new 12mm bushes from Bilstein will be a little small for the tube ID on the damper so you’d have to put a sleeve in there anyway.
The new 14mm ones I bought were too big for my early Bilstein dampers so I had to turn down the rubber, which wasn’t entirely successful but lasted until I bought a new set of the correct dampers a few years later.
Re: Which lower shock absorber bushes for bilstein shocks?
Posted: Fri Jun 19, 2020 8:41 am
by Lightweight_911
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If you're still having problems, another alternative could be to buy a couple of new M14 bolts (from ebay rather than a Porsche specialist) & get the threaded portion turned down/re-threaded to M12 x 1.5.
That way you can use your current bushes/steel sleeves.
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Re: Which lower shock absorber bushes for bilstein shocks?
Posted: Fri Jun 19, 2020 8:57 am
by Gary71
Definitely another option there, pretty easy if you have access to a lathe and I guess you already have your old 14mm bolts you can use.
Re: Which lower shock absorber bushes for bilstein shocks?
Posted: Fri Jun 19, 2020 9:03 am
by Lightweight_911
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The reason I suggested buying some new bolts is that the earlier M12 bolts used with the steel trailing arms were slightly longer than the later M14 bolts (90mm vs 85mm).
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Re: Which lower shock absorber bushes for bilstein shocks?
Posted: Fri Jun 19, 2020 9:21 am
by inaglasshouse
Re: Which lower shock absorber bushes for bilstein shocks?
Posted: Fri Jun 19, 2020 2:26 pm
by alanjf
Thank you all, This is all REALLY helpful and I can hopefully come up with a solution! Feels a bit like working on my old Land Rover rather than the Porsche! Alan