Converting axle underslung to overslung

[muddy_hollow]

On my Caravanner I replaced the axle with a new axis one and the clearance between the axle and the frame is not very much. It rides well but I noticed that during a really bumpy road that it grounded out (i.e. axle hit the belly pan).

Since this is a leaf spring suspension, what are the implications of converting it to an overslung configuration? Meaning, mount the axle under the leaf spring versus ontop as it is now...

Thanks

Mud

[overlander63]

Originally Posted by muddy_hollow

On my Caravanner I replaced the axle with a new axis one and the clearance between the axle and the frame is not very much. It rides well but I noticed that during a really bumpy road that it grounded out (i.e. axle hit the belly pan).

Since this is a leaf spring suspension, what are the implications of converting it to an overslung configuration? Meaning, mount the axle under the leaf spring versus ontop as it is now...

Thanks

Mud

I did this on a Boles Areo a few months ago. It worked quite well, though I wasn't able to reconnect the shock absorbers. You'll have to drill a hole for the locating pin through the top of the axle tube, and maneuver everything into place.

[muddy_hollow]

Originally Posted by overlander63

I did this on a Boles Areo a few months ago. It worked quite well, though I wasn't able to reconnect the shock absorbers. You'll have to drill a hole for the locating pin through the top of the axle tube, and maneuver everything into place.

The axle is a straight axle with leaf spring perch welded on, so I figure I could just flip so the perch is positioned over the pin at the bottom side of the spring. How much height did you gain?

I'm a bit concerned about raising it to much.

As for shocks, I've got new spring plates with sock mounts welded on. I think I would need longer shocks.

I was also thinking of purchasing longer leaf spring shackles. Are there drawbacks to longer shackles?

[easyride]

The longer the shackles,the more sway you will incur,ran many 50`s Chevys with the long shackles,looked cool,wouldn`t corner worth a da**. Dave

[markdoane]

If you have a straight axle with 12" brakes, I don't think you can invert the axle because the mounting flange for the backing plate is a 5 hole design.

10" brakes may work because the flange is a 4 bolt pattern.

You could cut off the perches and weld them back on?

The rise you get will equal the thickness of the spring pack, plus the distance from the perch to the centerline of the axle.

You may need to buy a taller step.

[muddy_hollow]

It's a funny thing, that without the perch on the axle I think there would be enough clearance to the frame. I saw the axle work on vintageairstream.com and he must have ordered his with the hole in the axle already as his doesn't have a perch..... Could the axle be drilled?

I thinking that putting the axle under the spring will make the trailer way to high so that leaves me with having longer shackles.

What about bump guards on the frame? Weld on some poly bump guards with the idea that if hitting a good sized bump that a guard would at least cushion it. Any thoughts on bump guards?

[samb]

Check with your trailer supply store. My local trailer supply place sells the perches separately, so I bought two and welded them on to move the axle and raise my trailer. Saves some labor and makes it easy to put it back the way it was.
Like markdoane says, some measurements will tell you exactly how much this will raise your trailer.
Sam

[markdoane]

I don't think it's a good idea to go without perches. Every time you apply the brakes the axle will transfer torque to the leaf springs. Kind of like torque wrap-up in reverse.

That will start to wallow out the hole you drill in the axle, or worse start to shear the head off the bolt that is holding your spring pack together. Might work ok for a couple of years.

Bumpers and longer shackles might get you enough clearance. Also, good shocks will prevent some bottoming out.

[JimW]

Mud, you stated you replaced the axle, but didn't say if you replaced the springs. Due to a broken spring on my 5 year old SOB, (which I sold today!) I ended up replacing all 4 springs. The new springs raised the trailer enough that I had to raise the ball on the hitch. The trailer sat 2 to 3 inches higher than before. I was amazed at how much the springs had settled in 5 years.

So my point is, would a new set of leaf springs give you the clearance you need?

Jim

[muddy_hollow]

Yesterday I called over to Spring Rebuilders and dropped them off at lunchtime. Today they were ready and the guy said I should get 2-3 inches out of them!!!.. They replaced all the clamps and replaced the second leaf layer with a new one. They look great and much more sturdy than a week ago.

Waiting on my leaf plates to arrive, then taking them over to a Friends to stick weld the shock mounts. I'll post progress.

[markdoane]

You don't say what tires you have, but if you have bias tires and want to switch to radials, be sure you have enough clearance for the shocks when you weld on the new mounts.

I welded mine to the opposite side of the spring plate to gain enough clearance. The upper shock mount was moved to inside the frame

[muddy_hollow]

I've got bias tires and doubt I'll change to radials in the short term. The trailer had shocks originally, and the planned configuration is similar to how it was before. I did order taller shocks just in case I need them. The old ones are in good shape still.

Need to get this all wrapped up to field test it around town and then head out to the birthday bash at Bakers Acres.

Even ordered new vintage hubcaps today....

[muddy_hollow]

After work last night I went over to the spring show and purchased new plates and shackles. Spent the evening grinding the shackles and fitting everything. Just need to purchase some new bolts for the shocks, but otherwise almost ready for tires.

I re-used the original shock mounts and bolted them to the leaf spring plate. This should do fine, as I upsized the u-bolts and leaf spring plate to 5/8" diameter u-bolts vs. 9/16". Pretty beefy.

I don't see it on other trailers but would a nylong bolt be good to spin?

Here are some pictures.

[muddy_hollow]

Fron the side

[muddy_hollow]

Spent the afternoon moving the axle under the springs. The job didn't take long but I've got some work to re-attache the shock mounts.

I'm a bit concerned that it's now too high.

Here's a photo.

[richinny]

what is the ball height with the trailer level?

[muddy_hollow]

Got up early this morning and hooked up the rig for a test ride up to Springrebuilders in Worcester. The goal was to have them look it over and tell me my options.

Towed fine, no sway. But when I got there the tech looked it over and said it looked dangerous as it was so high. They're keeping it overnight and they're gonna re-curve the springs and switch it back to the axle over the spring.

I like working with these guys so far. Good advice and they don't seem to be out to screw you over on selling you to much, plus the materials that I've purchased from them are top quality. Will report back with pictures once it returns.

[muddy_hollow]

The shop called me just before lunch to say the work was done and ready to be picked up. I shot up there over lunch and picked it up. The shop techs, re-curved the springs, re positioned the axle above the spring, and aligned them. Now it sits as an Airstream should.

The ride back to the house was uneventful and no sway or nasty noises from the rear. This without shocks, as I did not give them to the tech.

Overall, new axle, hubs, breaks, re-curved spring, added capacity to the spring, heavy duty shackle and U-bolts, bump stops, and replaced all the grease bolts for under $1000.

Here's a picture of how it sits finished.

[muddy_hollow]

Crawled under with a better camera to snap pictures of the new set-up

[Action]

That's a beautiful thing!

>>>>>Action