Radius Arm Install

[Markunderwood]

Hello
Slowly but surely putting the car back together. I am now finishing up the rear suspension and need to attach radius arms to the bottom of the car. Purchased new and measured to make sure they were identical to those taken off. Now looks like this is going to be a struggle to attach. Is there a trick to this procedure. See photo. It doesn't exactly line up with the car bottom attachment point.

[NigelW]

When I installed the radius arms after an extensive rebuild I had the same problem. The only way I could get it to line up was with the use of a ratchet strap on the wishbone and the other end on anything immovable (without pulling the car off any stands!). You might like to put a bit of copper grease on the mounting as if you need to get it apart in the future it will be a lot easer.

BTW does anyone know how to access the archived forum? I started a multi page thread on my IRS rebuild.

[cass3958]

Mine were the same which was down to new bushes all around and no play to be able to line them up. Like Nigel I fiddle about with ratchet straps until they were close then placed a bottle jack under the arm and jacked it up pushing the bush into place before doing up the bolt. They are very tight and I think I made the mistake first time around of getting them lined up with the car in the air and tightening them up thinking job done. I then drove the car on the road for a year and at the next service I found the radius arm bushes were split and needed replacing.
I would suggest that once you have them in place you leave the nuts and bolts loose and lower the car down on to its wheels, even take the car for a short slow drive up and down the drive, braking and accelerating to allow the bushes to settle before tightening them all up with the weight of the car on them.

As for the Archive I noticed this was gone last week. Perhaps Tom has either removed it or been able to amalgamate it back into this Forum. Either Tom or David should be able to update us on that side.

[Glyn Ruck]

It's a while back now but I'm pretty sure we had the car on it's wheels on a hoist and put on the handbrake so we could rock the whole bridgepiece backwards & forwards on it's V mounts until the radius arms lined up.

[JCS]

The reason the radius arms do not line up is that the suspension has not been set at normal to full ride height. You can either place a load in the boot (trunk) with the car on its wheels or make up tool J25 the dimensions of which are shown on page K15 of the workshop manual to set up the ride height.

If any car has had the suspension bushes finally tightened before being driven on the road the suspension ride, steering or general road holding will be suspect and bushes are likely to fail prematurely. Any car in that condition will require the offending joint releasing and ideally being driven, followed by the bush joint being retightened. This procedure should also be followed with subframe mounting attachments.
This procedure was not only expected by Jaguar but is usually confirmed in all the workshop manuals.

[Glyn Ruck]

Re reading section K of the Service manual we pretty much did it to the manual. Lining up radius arms/bushes was certainly no issue.

[NigelW]

I refitted my IRS by the book including the ride hight setting with links I made to the correct dimensions and had the monts slack but still had problems aligning the radius arms with the mounts. I always get the weight of the car settled with the front suspension before tightening the bush bolts/nuts.

[Glyn Ruck]

Seems we just got lucky rocking the bridgepiece against the handbrake on her wheels.

After Rob's warnings about premature bush failure I checked my radius arm floor bushes the other day & they are as new.

[cass3958]

I was under my car today and checked the radius arm bushes and what I saw was not pleasing. Looks like I am going to have to do them again soon. Both front and rear bushes on the radius arms, both sides, are showing cracks. I have a spare set of radius arms so I think I will order new bushes and prepare the spares for fitting. That will be the third set in eight years. Back under again tomorrow so will take a photo.

[Glyn Ruck]

Mine were genuine Jaguar supplied by Barratts in 2013. Maybe you should try some polyurethane bushes but they are a hell of a price.