Fitting Rear Suspension spring arm onto torsion bar

[conrod]

Can anyone please assist -
I am just in the process of fitting the rear spring arms to the chassis of my Jupiter - they have a hexagonal (ish) fitting - what angle do a need to try and achieve without the weight of the axle on ?
I am assuming that once the axle is fitted and the car sits on its own weight, it will change the angle

[Forumadmin]

It is better you put them back in the same side as they came out, as the realignment otherwise might stress them. But do not worry too much if you do not know.
Make sure the threaded end allows you to pull them out. That is in the fixed end.
They will only look right in one position unless they have twisted. I have a number of spare rods and select two that have the same amount of twist.
Copper grease hexs.
Fit the swing arm and align it with the top bush of the axle when the axle bump stop is about 7 inches from the bump rubber tip.




More in this post of 03 Aug 2017 09:43 am. viewtopic.php?f=1&t=4206&start=180

[David Morris]

Hi Conrod,

Keith wrote :- It is better you put them back in the same side as they came out, as the realignment otherwise might stress them. But do not worry too much if you do not know.

I don't know about Jupiter's, but they somehow got reversed on my Javelin during the rebuild, and she was very low at the back until we swapped them over. I seem to remember it was less that a 'flat' on the hexagonal end of the bar, but enough to make the car sit low and 'bottom-out' when there was any load in the back.

Swapping the arms, side to side, cured this problem. So, try and put them back on the right side, or reverse them if your Jupiter seems to sit 'low'.

All the best,

David

[conrod]

Thank you Gentlemen
Tomorrow is the big day to fit them back on -so hopefully with your guidance it will be fine
Will report back in due course

[conrod]

8 days later I am still struggling, When fitted the car sits to high -
So I need to go back to basics if you can assist
1) Do you fit the spring arm to the torsion bar first or to the back axle ?
2) How high should the back axle be off the ground when fitting ?
3) when the spring arm is on the torsion bar - what angle should it be and should it be pointed up or down ?

Would it be wrong to have the axle without wheels on the ground - fit the spring arm to torsion bar from this point and then when fitted, jack the axle up and fit the wheels - would it damage the torsion bar ?

Any help would be much appreciated

[Forumadmin]

1) Do you fit the spring arm to the torsion bar first or to the back axle ? No fit the torsion bar in chassis. Then put rubber into chassis, unless torsion bar does not fit in centre in which case put into spring arm. then fit spring arm onto bar.

2) How high should the back axle be off the ground when fitting ?Fit shock absorbers and fit shock to axle. This will put axle approximately at max droop. Then get axle at height to put bolts through upper arm. Fit lower arm to chassis then try to fit to axle . You should need to pivot front of axle to get correct angle of axle input shaft to locate spring arm. You may need to pry one side of axle up or down to locate. Fit Panhard rod last fitting washers to suit, locating axle in centre .
3) when the spring arm is on the torsion bar - what angle should it be and should it be pointed up or down ? See photos.


You may need three of four jacks to do this. One under diff drain plug one at each shock mount point and one under front of diff pinion. The chassis should also be supported on axle stands

[conrod]

Thanks for the info - I have also found out that I have been using Javelin spring arms which seem to have a different profile - will keep you posted

[conrod]

Sorted - at last - thank you
Still very slightly high - but no fuel tank etc in yet and I think the torsion bars settle
Many thanks for everyone's help and advice
I made it more difficult trying to fit Javelin spring arms - they are quite different

[Forumadmin]

The parts book shows the Jup has the same spring arms as the Jav (both early and late). Scott and I also did a visual check on two spares which seemed to show they are the same.
Note that the left and right are different so could be put on the wrong side. Also the spring arm you had could have been modified.

[conrod]

Yes I think you are correct in that they have been modified, as without question they sit at different angles
Thanks for all your help