Rear radius arm substitute

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Ride_on
Posts: 2262
Joined: 26 May 2009 05:34 pm
Location: Belfast, N. Ireland

Rear radius arm substitute

Post by Ride_on » 05 Nov 2011 12:19 am

Well I'm still trying to sort a solid replacement for my rear radius arm / axle control arm.

No sign of any bushes to replace in the old arm, Dia did suggest he might get them done but its not his full time job, and it will be tricky, especially the press fit one at the chassis. Someone also suggested rose joints so I am going down that route at the moment and come up with some strange discrepancies.

The large end at the chassis has a 12mm hole in the bush core but the hole in the chassis is only 10mm, so it seems the original design has a 'loose' bolt relying on the clamping force to the chassis. Anyone confirm or deny this, is there a sleeve missing? What is the bolt length? (I've forgotten which bolt is the right one)

The other end is a 10mm hole.

Both are 32mm wide.

The M10 rose joints are only 14mm wide, and I got tapered washers to go with them, building it out to 24mm, leaving a 8mm gap or a 14mm one if you include the 3mm washers normally fitted at the axle end. So I could replace the 3mm with 7mm washers/spacers, or get 4mm additional ones (maybe better to standardise both ends as the chassis end doesn't have additional washers).

Alternatively I could go for M12 joints and add in M10 converters which will build them out more.

I plan to make a straight linkage and let the rose joints take up kink, get some 17mm heavy tubing and weld M10 bolts on. Both joints are right hand thread so it can only be adjusted by 0.75mm increments (turning one joint 180deg), I figure that is fine as the axle end is adjustable.

Is there likley to be a significant increase in road noise, since I am no longer bushed?
1980 345 DL_______1987 360 GLE (project car restored to GLT spec and B230FT'd)
1984 360 GLT______1987 360 GLT
1983 360 GLS______1989 360 GLE
1985 340 GL_______1986 340 1.4
1985 360 GLS______1995 940 SE 2.3 Turbo Estate (daily)
1987 340 GL 1.7

Ride_on
Posts: 2262
Joined: 26 May 2009 05:34 pm
Location: Belfast, N. Ireland

Re: Rear radius arm substitute

Post by Ride_on » 16 Nov 2011 12:55 am

Well I got 2 M10 rose joints in the end, cut the ends off my old radius arm (15mm OD, 11mm ID pipe) welded on some hex joiners and packed the joint out with washers.

If it needs a big adjustment it will be ackward because I got 2 RH Thread rose joints. I could have gotten one LH thread one and the arm would have been adjustable by turning the rod, but the LH thread nuts etc were only available in large packs, and I just didn't need the flexibility.

Also got some rubber boots for the joints, that will be fun trying to get them on, its thread a camel though the eye of a needle job!.

All done now and just need to adjust with the weight on the wheels + dog in boot (she is a handy 25kg). I might try and adjust for level axle base. I hope it won't be too noisey without the bushes, am aiming for a luxury sport with all the sound proofing :D
Attachments
IMG_2934s.JPG
Rose joint rear radius
1980 345 DL_______1987 360 GLE (project car restored to GLT spec and B230FT'd)
1984 360 GLT______1987 360 GLT
1983 360 GLS______1989 360 GLE
1985 340 GL_______1986 340 1.4
1985 360 GLS______1995 940 SE 2.3 Turbo Estate (daily)
1987 340 GL 1.7

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