Is my leaf spring broken??

[ericpost]

Hi,

I new to the board and I'm also the proud owner of an 1972 GMC Jimmy with a bunch cool modifications. This was my first 4X4 build so I learned ALOT of new stuff.
So on to my question... Lately I've noticed a thumping sound when I turn my wheel back and forth, the thumping happened in both directions. Not knowing what it was I climbed under and had a freind start turning the wheel. After 5-10 minutes of watching we noticed that the thump was coming from the drivers rear spring shackle. It was caused by the middle (of 3) leaf sliding left and right and hitting the the shackle hanger. I also noticed the upper leaf had a rub spot from the middle leaf sliding forward and back when it travels over bumps. This was not the case for the passenger side leaf spring. Does this mean I broke a leaf spring? Also as a temporary fix can I run a grade 8 bolt thru the spring to hold it while road driving (not off-roading)? While I'm asking how do I tell the lift? I bought this truck with a lift but don't remember how much of one. I think it was a 3 inch kit but not sure, plus I wouldn't trust what the lift was from someone selling a truck.

[JIMs70GMC]

When you say moving at the shackle end hitting the shackle is the front end also moving the opposite direction? There should be a metal clip wrapped around all the leaves of the bunch like this:


If it is broken your going to have one heck of a time drilling through the spring metal.

Welcome to the board. Any pictures?

[Mudder]

there should be a bolt going through the middle of the springs now. you should be able to see if the spring has got a break in it.

[ericpost]

The middle spring seems to float so yes the other side moves the opposite direction. There does seem to be a rivit towards the rear of the spring which looks like it should hold the top and middle spring together, but it is definatly not doing what I think it should. I could try to chisel the head off and pop it out. That should get me started on drilling a hole if needed (believe me I was not looking forward to drilling a hole in spring steel!!!). I have a clip as well that wrap around the springs but I can slide it back and forth its so loose. I considered welding it but started thinking the integrity of the steel would be compromized so I didn't bother. I guess what I'm hearing is the spring is technically broken, if a bolt thru them will help I'm willing to give it a shot. I can also try to tighten the clip. I can't spend any more cash on her until winter so it looks like mild trail driving and commuting for the rest of the year.

I'll take some pic's tonight and show you what I mean.

Also any ideas on how to tell the amount of lift in case I do need replacements? Would measuring distance from axle to frame on a stock ride and mine give me a resonable estimate? Currently I'm running 33X12.5's and I don't rub... but it's really close.

[Mudder]

And make sure your u-bolts are good and tight. Use a cheater bar if u must. those clamps can be heated and made tighter. use a big hammer. they shouldnt be so loose as to be sliding back and forth. does the truck have lift blocks in the back?

[ericpost]

There is short blocks at the back. I've never seen a stock '72 before so I thought they might be stock, they apprear to be 2-3''. I guess if stock trucks don't have blocks I 'll know my lift if I measure those!

Good point about the dam ubolts, I changed my front end recently...... I did reef a breaker bar pretty good, at least I thought I did. I'll re-reef when I get home.