6 inch Lift, home design and build

I have been Jeeping for years, and love to spend time camping. We recently had a daughter, and I figured a trailer would be the way to keep camping a reality for our family. I picked up a 1999 starcraft single axle hybrid trailer that had been damaged due to a tire blow out. Fixing it has been a fun project and we have one great camping trip under our belts.

Knowing where we go, I knew the trailer needed more height. Due to locations of the grey tank lines, I needed to lift at least 5 inches in order to keep the plumbing lines connected in one location for draining. I picked up some 2x6 steel 3/16 wall tube. I figured 1/4 inch was overkill, and 1/8 wall didn't seem quite strong enough to carry the weight.

The Starcraft Travelstar 17CK came with a torsion axle, easy enough to lift. You can see that the stock axle rests on the frame, and bolts only to an inboard side flange.

https://imgur.com/H8s6wAo (see "factory install image")

I dropped the axle after making several measurements. I also dropped a plumb bob and marked the fenders as the line crossed the center of the hub. This was to ensure I could line the axle back up exactly as it was. The lining up of the axles would be even of greater importance with dual axle trailers.

https://imgur.com/cRlzKpy (see "removed axle")

I drilled the tube. The holes on the bottom are line up with the side holes drilled for the side flange. I left the 2x6 longer than the axle pad itself in order to disburse the load a bit further over the 2x4 steel of the trailer frame. I drilled in a series of holes with increasingly larger bits. I was out of cutting oil, so I filled the bottom of a plastic cup with WD40 and kept the bits cool by continually dipping them.

https://imgur.com/y55l9Mq (see "initial drilling)

You can see the holes lined up. I drilled the holes fairly high on the sides to get as close to the trailer frame as possible when mounting the flange.

https://imgur.com/Up3B7ne (see"all drilled")

I re-used the hardware that bolted the axle to the side flanges, and bought new hardware for the remaining as the factory install did not bolt upwards into the frame of the trailer. On both the axle and the flange, it wasn't easy to get to the hardware on the inside of the flange. It took a few tries. I used wrenches and screw drivers to pin the hardware in place while I tightened the hardware from the outside.

https://imgur.com/x5EMSEt (see "mounted to axle")

The bottom bolts were mounted and drilled slightly offset. The holes on the axle mounting pad are centered, but the axle mounting pad is wider than the 2x6 so they rest to the inner side of the landing pad.

https://imgur.com/TldReYO (see "axle rear view")

The stock flanges were stitch welded fairly strong around the inner and upper side of the frame. Before mounting the axle, I stitch welded a few spots between the flange and the trailer frame to provide additional lateral support from the flanges. I left the hardware a bit loose until the axle was raised into place and everything was measured and lined up properly. The hardware was all tightened down before and welding took place. With just the hardware tightened, everything felt very solid.

https://imgur.com/8VJhX0i (see "stock flange")

I used a jack to raise the axle back up into position. The trailer was supported with four 6-ton jacks, one at each corner during this project. I bolted the new tube to the inner flange, high and towards the trailer frame for good support.

https://imgur.com/NoOLoee(see "bolted high")

I stitch welded the spacer lift to the frame

https://imgur.com/pwCjtGo (see "initial stitches")

I then stitch welded the rear flange to the lift spacer.

https://imgur.com/Z37dmqK (see "rear stitches")

When this trailer was built in the factory, I believe the frame rails were constructed about 1/8 of an inch too far apart. The "driver side" if sitting in the tow vehicle, was slightly bent inward. The axle took a bit of prying to get it down when I removed it because it was pinched in place. I spaced the blocks on my axle to match the frame, and then used a c-clamp to move the flange back outboard and weld it in place. 

https://imgur.com/MJ6Eo2b (see "c clamp flange")

I had some left over 2x6. I cut the edges off of both sides to make some c channel. Although the stock flanges provide some lateral support, after lifting this high, I wanted to make it more ridged to ensure there wasn't a failure of the lift block attachment.

https://imgur.com/Equ9S0X (see "c channel")

With the c channel stitch welded in place, the axle feels solid and isn't going anywhere. With the lift block sandwiched between these c channels and the inner factory flange, I should't have any side to side flex that would over stress the welds.

https://imgur.com/YjkM3ut (see "lateral support")

Here's a side view of the supports.

https://imgur.com/EHe2UG6 (see "side view")

I also tacked the axle to the lift. If the axle needs to be removed, It isn't so much that it can't be ground down.

https://imgur.com/biCGiOB ( see "tacked to axle")

A bit of rusty metal primer to cover everthing after wire brushing the welds. I later covered it with undercoating.

https://imgur.com/U3zPGBz (see "primed")

Our initial trip was to 4 hours south to Moab UT, a great way to break in the new lift. Over washboard roads and curves, everything is solid. The trailer tracks really well and doesn't feel sloppy on the corners. There is no cracking or movement in the lift welds, everything remains strong. I will continue to monitor its strength over time. I am really happy I lifted it. I was nervous about damaging the plumbing due to how low it was. With the current height, I am much more comfortable. The tow vehicle has a fairly tall tow point (lifted jeep, aftermarket bumper that moves the receiver up even further).

With the lift, I also went to a larger rim and tire. I could have gone larger, but I decided a 205x75x15 was a fairly common tire size and a good choice, without too large of a sidewall. The original rims were 13 inches with 185x80x13's. The tires look good this size, and everything is proportioned well with the lift. There is plenty of clearance, and the larger tires will not impact the body of the trailer as the suspension moves. With the larger tire diameter and lift, the trailer sits 7 3/4 inches higher than it did before, exactly where I wanted to be.

WOW!

A ton of work, a labor of love.

Excellent job!

The manufacturer could learn from you.  ;D

Thank you. It was actually a fun project. I started at about 10 AM on a Saturday, and was spraying the primer at 5:30 that day. Drilling took the longest amount of work time. Going back and forth for tools and a few items from the hardware store also chewed into the time. It was done next to a friends garage (to use his welder), so i had to run back home a couple of times for more tools. I'll need to get some pics of it behind the jeep to show the stance. It looks much better, it was way too low to the ground before.

Very nice work.  Some suggestions

Always best to have reinforcing end at the corners of the HSS.  By ending it before the corners the wall of the HSS deflects.

Cap the HSS to prevent it from filling with dirt

Additional height increases torsion on the frame. Consider adding a side to side brace.

Seal weld the seam between the HSS or caulk the seam with with urethane caulking before painting.

Thank you for the input. I had been thinking about capping the tube, but haven't done that yet. I was also thinking about adding a tube just above the axle for the exact purpose of frame twist, but again haven't taken that step. I was planning to add it near the bottom of the 2x6, with a triangulated gusset from the top of the tube and to the 2x6 and the back side of the factory flange, once again tying everything together.

I don't know what HSS stands for, but you seem to be referring to the steel 2x6.

And do you recommend sealing between the 2x6 and frame to prevent water penetration and corrosion? I was going to simply use rubberized undercoating on everything, but can certainly seal it tighter. I actually used windshield urethane the seal the new inner fender I made for the side that was damaged by the previous owners tire blow out, its great sticky stuff.

85IrocZ-28 said:

I don't know what HSS stands for, but you seem to be referring to the steel 2x6.

Click to expand...

https://en.wikipedia.org/wiki/Hollow_structural_section

That sound good. Gusset on the edge the cross tube.

For the time is takes I seal weld.

If seal welding isn't in the works I'll clean off the mill scale (grind) preferably before welding the pieces on.

After welding the seams are cleaned and then caulked with urethane, then primer/paint.  White or grey paint makes any future issues visible.

You're right about window urethane is like roofing tar.  I'd use it not the undercoating. 

Undercoating traps water which accelerates corrosion. It is hard to find the areas that water is trapped.

Removing undercoating is a horrible job.  Removing urethane is not easy but it will come off with a wire wheel