Shackle issues

[warren57]

I installed a set of re-arched springs to raise the rear up a few inches. They are stock length, but the eye to eye measurement is slightly shorter due to the arch being tighter. Springs went in with no issues, new bushings and shackles. The problem is when I raise the car on my lift, the shackles spring up (hitting trunk floor), so when you lower the car you have to pry bar them back down before setting all weight on the wheels. Once weight is on the wheels it's no problem.
Not a big issue at home on my lift, but I'm concerned if I'm on the road and have to jack it up to change a tire. I'm sure they will spring up the wrong direction and laying on the side of the road trying to pry the shackle down isn't my idea of fun.
Anyone have thoughts on a possible solution other than lower springs (less arch)?
Today I tried loosening the shackle bolts, compressing the springs with straps and come along and re-tightening the shackle bolts. Al this to insure the rubber inserts weren't causing torque and twisting the shackles up. Not sure if it did any good, got to hot out and I came in the A/C for awhile!!!
I attached a few pics. Don't know if you can see it, but the pivot points are nearly vertical with full weight on springs. Actually in the first pic I plumbed the bolts with a level and the lower bolt is slightly foreword (about 1/4").
shackles 003.jpgshackles 002.jpgshackles 001.jpg

[chevynut]

Warren, I thought you said you re-arched the springs to LOWER the rear. I guess I misunderstood what you were doing. I think what you're describing is a common problem. I'm not sure how guys deal with it. Hopefully someone can help you.

[warren57]

It's not to big a deal. I may install a rubber snubber to try and keep it slightly below horizontal, then when you re-apply weight it would automatically go to the down position as pictured. The problem arises when it swings above horizontal, them when weight is applied, it goes upward and hits the bottom of the trunk.

[Run-em]

One way to deal with it is to reposition the rear shackles forward. That would keep the shackle from going over center & then popping toward the floorboard. But then they would probably hit --spring eye & shackle -- during normal suspension changes. If you run a longer shackle that would work, but- that would defeat the purpose of re-arching the springs in the first place. Another method would be to re-drill the spring eye bushing to position the shackle bolt in the spring eye to restore the stock geometry of the mounted shackle....but where are you going to find blank spring eye bushings. Heard of a young man many years ago that solved just such a problem by adding a few headless nails into the front portion of the spring eye bushing --forcing that portion to be "harder" and keeping the shackle further towards the car rear, and that solved his problem.

[warren57]

Raised the car up today after loosening the shackle bolts, loading the springs and tightening. Seems to have worked, at least fr now. When raising the car the shackles stayed below midway and turned down when weight was re-applied...

[warren57]

Well the shackle issue never went away. So, I extended the stock shackles about an inch at the angle of the spring arch and everything works great. I'll post pics when I get a chance.


So I added about an inch to the bottom of the shackle at the same angle as the spring arch (essentially lengthening the spring) Tig welded. Now it swings back instead of up when weight is applied.
The first picis with about 75% weight applied. The second pic is with no weight on the springs.

[slowfinger]

Warren, We recently installed shackles and springs also in the 56. Wondering also if a tack weld at upper shackle bracket to shackle would also work? Or would that effect ride too? Was wondering.... Geo.

[Rick_L]

Tack welding the shackle to the bracket will do one of two things, neither good.

1. The tack weld will break.
2. If it holds, you will have no spring action. The shackles have to be free for the spring to compress or extend.

[chevynut]

It wouldn't be difficult to weld or bolt a stop on the side of the frame to prevent the shackle from flipping. If it only does it when you jack up the car, it would have no influence on normal driving. If it flips when driving the car you have bigger problems.