78 Seville Rear Spring Shackle “Pivoting”

[CadillacFlashback]

I noticed that the left rear wheel of my 78 Seville looked like it wasnt centered in the wheel well.  Discovered that the rear spring shackle was "pivoting" and allowing the spring end to rest against the frame rail. On the other side the shackle keeps the spring suspended about 5/8-3/4" below the frame.  This "pivoting" is allowing the left end of the axle to slide rearward which is why the wheel looked displaced. If I jack up that wheel to relieve the weight the shackle falls back to the correct position, and if I wedge a piece of metal between the shackle and frame the wheel stays in the proper place.

Do I need new bushings in that shackle? If so where can I find that part? Or are there other suggestions?

Thanks

[TMoore - NTCLC]

I have had this happen multiple times on my 1942 when the rear end has been lifted clear of the ground and then set back down and the spring has settled into the wrong position. It usually takes more than just lifting the car to get it back into place (crow bar while the car is lifted to shift it back into the correct orientation).  Once the car is back down, I have never had a situation where it was able to shift to the wrong position.

I have never had this happen on my 1979 Seville, but I can see where it might be possible. I have not detected any excessive play in the bushings on either car, but others in the forum may be able to provide more info on what to look for.

[Dave Shepherd]

This happens on my hotrodded 51 Belair.  I put a bar between the rear hanger link to prevent this when lifting the rear of the body. This seems to be common on that type of rear spring hanger.

[35-709]

My '42 would do the same when on a frame lift.  Below, 2 pics of what to do to prevent it.  One for use each time, which I did, the other, a more permanent fix.
Both of these solutions, courtesy of other posters here some time back.

[CadillacFlashback]

If I am understanding these responses, your issues have been that lifting the car creates a bad spring orientation.  In my situation it is the opposite-when the car is raised with no weight on spring in falls to the correct position, when the car is on the ground the shackle pivots rearward resting the spring end on the frame rail which allows the axle to move backwards.

If I wedge something between the spring end and the frame it stays in proper place but I was hoping for a more "correct" solution.

[Seville Life]

Gentlemen, I think you're looking at this the wrong way around. If the car settles on the suspension low enough that the rear shackle moves rearward allowing it to touch the frame rail it means you have a sagging leaf spring assembly?

The leaf spring is at a fixed point at the front - so no movement fore and aft. The rear shackle can only move rearward if the leaf spring extends it's length, that can only happen during normal road-use suspension travel or, if the car is stationery, by a sagging leaf spring.

I love these cars, run a '78 Elegante. I'm in the process of putting together a '76/'79 Seville Alternative Parts Book, ie, where exactly did many of our Sevilles come from? Yes a few Nova parts, suspension-wise quite a number of Camaro parts, some Oldsmobile and many Cadillac-only parts.

Look after those rear shackle bushings. Why, because you cannot buy them. Notes from the Serviceman tell us that early Sevilles up to 3000 the cars had a much lighter weight shackle assembly on them. They had complaints of rear end vibration at highway speeds and o changed the complete shackle assembly for a much heavier one. The new version had a bolt and a thick metal sleeve and rubber bushings with a much bigger hole through the centre. It's these bushings that are hard to find.

You'll find lots for sale, but look closely, they have a much smaller hole through them, they obviously fit the Novas and possibly other cars. TRW made them but I don't have a part number.

I hope that makes sense.

The other thing to remember is the durometer reading of the rubber in the bushing. Most new bushings have a much harder rating than our Sevilles, that's because they're really for Camaros. There are some NOS ones out there, buy by part number. I have two originals to fit when needed. Paul

[Seville Life]

I forgot to add another little oddity that hasn't been noted on these '76/'79 Sevilles.

Sway bar (anti-roll bar) link assemblies. Today manufacturers list the front and rear link assemblies as the same part?  Sadly this is not so, the rear links are shorter. That's a shorter bolt and tube/spacer. The bolt is only threaded at the end, so it has to be the right bolt.

I have the Product Assembly books and Cadillac state that the sway bars must be parallel to the road? If you use the (wrong) longer link kits the forward end of the sway bar is too high? I have searched and cannot find any correct rear sway bar link kits off the shelf.

I have discovered that the front link kits for a '78 Eldorado are the right length. I haven't fitted them yet though so we'll have to wait for the end of this story.

I had thought about putting my '76/'79 Seville Alternative Parts Book online? Paul

[fishnjim]

Since it appears to be on one side and not both, then some defect exists there.
A spring or differential shop may help sort it out.  Need to do an inspection on the lift.   Alignment can/will be out, etc. giving excess tire wear.   They'd re-arch and/or replace all or part.  I'd do both sides at this point. 
Probably from lack of maintenance and bad shock absorbers over time, but just guessing.  Note the mileage as that's a good indicator of wear.

[Seville Life]

Just thinking about this my friend, I think you have a sagging spring...but...

...the only other possibility that would allow the rear wheel to not be centred in the wheelhouse would be the U clamp and two studs that hold the axle to the leaf spring assembly? I've never heard of them working loose but you could just check them with a torque wrench to be certain all is well. Paul

[CadillacFlashback]

After a visit to a spring shop on Friday it seems replacing both springs is the best way to go.  They are not expensive and that will remove all doubt.  Thanks to those who responded.

[Roger Zimmermann]

If you are replacing the springs, I'm at 99% sure that the same issue will happens. In my opinion, you have a shock absorber which is too long, allowing the spring assembly to pull the shackle in a unstable position: when the car is lowered on the floor, the shackle will be pivoting either up or down. With new springs, you will have the same situation.