Shackle problem

I'll make it to the Meltdown, but obviously not the Heads Up Drags. There was too much to do in too short of a time. Even if I had figured it out earlier in the week, and could get the right bushings in time, it would have been a mad dash to get it there and just barely p*** tech. The Meltdown Drags, OTOH, are a month away. Mwuhahahahaha!!!

 

So, I rebuilt the correct HD (heavy duty) rear springs. They match the length of the original LD (light duty) rear springs, So I'm good there.

However, when I installed them, the shackle angle is slightly MORE severe. In other words, it's still laying almost flat.

The front and rear mount points are exactly the same distance apart as stock. Spring length is the same. The only 2 things that changed from the original that could possibly matter is putting the axle on top of the springs and lowering the upper shackle pivot. Neither seem likely to make this large of a difference.

I removed the shackles and set the weight of the van on the springs. They only slid about 1/2", but I'm not sure if that was the end of their travel or they were simply unable to move any more because of the mount. Looking at old photos it doesn't look like the springs had much travel to begin with.

Here's the original springs with the van sitting on the ground. The spring is virtually flat i.e., not much stretch.



I don't have any good pics of the old shackle with weight on it. This is about as best as I can do. You can see where the shackle stuck in position. It probably sat a little further back still with weight on it.



The springs on top are the HD rear springs before I rebuilt them, and the lower 2 are the HD fronts that I accidentally installed on the rear in the beginning of this post.



Here, the black springs are the HD fronts rebuilt, and the rusty ones are the original, LD REAR springs for comparison.



I rebuilt the springs with spring liners from Speedway, so I'm sure that's allowing a little more slide than the worn out plastic disks that were originally there, but could it cause this much slide?

I suppose I could move the upper shackle pivot back up ~2" so it would be at the stock height. (you can see the hole in the frame above the shackle). That might correct some of it. However, this would involve major modifications to the weight, tank, and filler.

I could lower the pivot even further and move it back a little. Lowering it would allow it to clear the filler, but might raise the roll center and affect handling adversely. It would clear the filler and rear pan though.

Another option might be to use spring sliders, although these are supposedly just for Chrysler style springs and are for 2.75" springs (I have 2.25) and 1" spring eyes (I think I have 1.125). This might solve everything with some modification.



This is puzzling an I don't really know what to do with it.