Restoring Lifted Suspension M38a1

You should try it. A 4" lift is quite a lot though. I think the Superlift kit has a reputation for riding pretty rough - check old posts or maybe others will correct me. I'd likely try removing a few leaves and see what the height and ride is like. I would probably remove the leaves in order short to long, since intuitively it seems like you'd be putting a lot of stress on the longer leaves if you didn't remove them in that order.

 

It does ride pretty rough. I was looking at pictures of the superlift kits and none of them have the extra long shackles. So I wonder if that is above and beyond the 4" lift kit. Is there a way to measure to see how much lift I have?

 

If I were told it's a 4" lift, I would interpret that the shackles are in addition to the 4" lift. When you buy a lift kit, the advertised lift is all in the springs. The military manual for the M38A1 may give you a ride height or height of the bumper or cowl or something to compare to, and then you'd have to adjust for your tire height. I think the M38A1 manuals are online somewhere.

The seller could have installed a 2" or 2.5" springs and then added another 1.5" or 2" with the shackles, adding up to 4". See if Superlift offers a 4" kit and what other heights they offer, if any. The effect of the shackles is easy to figure - each inch of length adds 1/2" to the ride height.

 

I have a few thoughts to add.

Some spring companies use stock spring lengths to make their lift springs. When you add an arch to a spring, the eye-to-eye length decreases. This in turn creates angle issue with stock shackles. Longer shackles help (but do not fix) the problem. It helps prevent the shackles from having inversion issues by giving them a longer distance to operate, but they are still resting in an undesirable position (limiting downtravel and stiffening the ride a little).

I'm wondering if the longer shackles were added to help soften the ride, and the shims were added to try to recoup some of the caster.

As a side note, you can take 2" out of the shackles to lose 1" of lift, but if you remove your shims, you'll gain 1/2" of it back while only netting 1/2" drop in height.

Personally, I'd cut 2" out of the shackles, get rid of the shims if the caster is within range of happy, and remove the 4th, if not the 4th and 5th leaves out of the packs. This should get you back down to earth and flatten your leaves a little, have less sway with the shorter shackles, and help with the bump-steer. You might want to check out your pitman arm; it looks homemade? Check for play. Also check the blocks (or shims?) between your rear axle and springs. They look way short. They shouldn't be any shorter than the spring pads that are welded to the axle.

Good luck!

 

I have 3" Black Diamond springs on my A1. It has 35 12.5" tires on it in my profile pic. Currently it is running a much better suited set of 33 10.5's. Mine was all original and is a first year '52. I pulled the springs and C shackles. I replaced with stock length standard two plate style shackles. I did not modify the "screw" type shackles on the frame, I just hammered a urethane bushing into it. That's been 10 years now and I am quite happy with that combo. It looks to me that your springs may just be 2 1/2" and the shackle gets it to 4. I'm with the others that you should ditch the long shackles, lose the wedges and see what that does for it.

 

Thanks for the replies and suggestions. What is the length of a stock shackle?

 

2.750" center to center of holes.

 

OK thanks, the ones on there are 4.75" so I would lose an inch if I go to stock.

 

And the stock length ones look much less goofy and they should get the pinion angle and caster more in line with what the spring manufacturer built in.

 

This Jeep is almost identical to how mine was in 1984. Lifted, long shackles, 33" tires on 10" wide rims, 9" brakes, still f-head powered with manual saginaw steering with that same box location and column routing.

Tarry describes EXACTLY how the steering was. I would get in the Jeep and cinch my seat belt tight. Not because of any seat belt law or fear of crashing, but because I was a skinny 16 year old and needed the seat belt to hold me in place so I could steer the Jeep. Not only did I have to steer into every turn, but I also had to steer out of every turn. I think there was enough bind in that u-joint to kill any return to center of the steering.

After changing to a Buick v6 we switched over to power steering and a much better path for the steering shaft. I think the shaft upgrade was a bigger improvement than the power steering upgrade. I do still have one of the steering u-joints and shaft from the original saginaw setup if you could use it to incorporate another joint into your shaft to lesson the angle on that one joint.

 

Framer Mike P,
Thanks for the information. Are you able to post some photos of how you routed your steering with the power steering setup? I'll have to take another look at mine and see if a second u joint would help.

 

Just a quick update on the Jeep. I ended up buying a complete suspension kit from Walck's 4WD. It came with US made springs that are supposedly stock type. Installation went pretty smoothly except for the removal of the odd extra long shackles. They were attached to the frame with bolts through a metal and nylon bushing that was in the frame holes. Unfortunately the bushings were pretty well rusted into place. My dad, who is an artist with an oxy-acetylene cutting torch, was able to remove them without wrecking the threads in the frame.
For tires I decided to go with P225/75R16 all terrains mounted on the reproduction wheels. They look a touch fat but I think they will ride nice.
A small amount of driving showed the ride is must softer than on the old setup.
I still need to adjust the stops on the axle to allow for a tighter turning radius. After that I'll tackle the steering and see what can be improved there.
Thanks everyone for the suggestions and information so far.

 

Perfect height for the stock look. You got lucky with stock spring hanger bushings because you can break the head off. Did you notice any were left handed threads? I think the original design has to do with the shackle rotation and them coming loose but I can't remember.

 

From what I remember the right rear threads in the frame were LH. Also the bushing for the left front that went in the spring was LH. Everything else was RH thread.
The manual specified LH thread in those locations and the kit came with two hangars that were LH thread on one side.

 

Just check mine and that is what I have and I know I researched it at the time I installed them. The LHT (bolts/bushings what every they are) have a line on the point of the hex head so you know what they are and yes they are used just on the spring not the frame. Rear shackle will rotate CW on compression and that would tighten itself with a LHT and same with left front. Sounds like a quality kit.