Different trailing arms left and right

[ETW]

I just pulled off my trailing arms. I knew they were different because one has the ball mount for the sway bar. I took out the trailing arm bushings and they are also slightly different. One (I think the sway bar one) has slightly larger metal end caps whatever you call them and larger bushings. Just want to make sure they will both accept the same Elephant monoballs. I think it should be alright since Elephant lists those same monoballs for all 65-89

Thanks

[1QuickS]

Since no one else has responded I'll offer my 2 cents. The trailing arms are the same (left and right) but the one with the sway bar ball was for 911S or Normal 911s optioned with sway bars. So the one without the ball needs a ball to allow installation of a sway bar, not difficult to retrofit and there have been post regarding this procedure. Perhaps there are aftermarket sway bars that mount without the need for these balls at all.

As for the monoball installation, check the bore in the end of the banana arm, this is where the monoball goes so these need to be the same, don't worry about what came out; they may be different due the the trailing arms being different, possibly due to an "event" in the car's earlier life. Also the bolts will have the same diameter so the bore and the bolt diameter are the two interfaces of concern...the mounts on the torque tube should be identical as well.

[chris_seven]

I would agree with Paul that one is probably from an early SWB 911T or even a 912 which didn't have a Sway bar.

The ball stud is still available from Porsche and is easy to fit.

Have you been running the car without a Sway Bar? If you plan to fit one you will also need to ensure that your bodyshell has the mounts installed and if they are not you will also need to obtain these and weld them in place. You will also need a pair of drop links complete with bushes to suit your sway bar. These parts are all available from Porsche.

15mm dia sway bars are still available new from Porsche and we have made 16mm dia bars at the end of last year.

The rear Trailing Arm Bush has had the same part number from 1965 through to 1989.

There is no difference in the inner diameter of the trailing arm at this point apart from production tolerances. In my experience all steel arms both SWB and LWB have a very similar ID but the later Aluminium arms are very slightly larger but even this difference is only a few thou.

Looking at the bushes you have removed it seems as if the tolerance rings are still in the Trailing Arms and you will need to remove these sleeves before you can install either new bushes or Monoballs. They are quite tricky tp remove as they are in two pieces and don't knock out.

We usually run a small MIG weld around the bush and this shrinks the sleeve and allows it to be pried out more easily.

The variation in diameter is most likey due to uneven wear of the rubber insert which is not untypical.

The inner spacing of the Torsion bar tube mounting varies slightly in width over the years and there is a variation from the early to late cars of around 2mm. This may mane some spacers are needed depending on the length of the Monoballs you are planning to use.

When we designed our Monoball Cartridge we fitted an internal spacer which is easy to change and can accomodate width variation as we supplied a small pack of spacers of differing thickness.

If you decided to stick with Rubber bushings Deutsche Parts offer uprated rubber Trailing Arm bushes on EBay at very good prices and we have used them for several years and had good results for road cars where monoballs can increase transmitted noise.

[ETW]

Thanks for the replies. The car is actually a 912 so the ball mount trailing arm is the one that doesn't belong. I may even grind the ball off before I refinish them. One day when I add a rear sway bar I will go for an aftermarket one that mounts to the spring plate eccentric bolts

[crummasel]

Honestly i'd rather install a ball stud into the 912 one as you can be sure that also a 912 benefits from a sway bar. As you are in now you'd be done with it and you will not regret to have left out the opportunity. Plus if you have once shaved one ball off it will be difficult to fit in a new one later.