Sunday, March 5, 2017

Going Another Round with the Trailer Suspension!

As I mentioned in previous posts, we had problems with our leaf spring hangers last Spring.  Since that time, Dad has been inspecting the issue regularly. When he recently got under the trailer and removed some of the components of the suspension, he uncovered even further problems associated with the OEM (or as Dad explained the “original equipment manufacturers”) design.

Since Dad is better suited to explain what he found and document the repair process to our home on wheels, I am turning over the rest of this post to him.  (He’s got my head spinning already!  Time for cheese--my perfect cure for a headache!)

Thanks Popo. Well here is my one and maybe only shot at posting on his blog. (not maybe, Dad. This is definitely your only shot!  I've had to spent too much time editing!)

The first order of business was to make the areas of the suspension accessible, so I removed the tires on each side by un-torquing the lug nuts.  Once the tires were removed, I raised the trailer further by using the auto-leveling hydraulic jacks that support the trailer when we are stationary. Then I removed the weight from the spring hanger bolts in order to remove them. This was done by jacking each spring just enough to allow the bolt to slide out of the spring. I also placed blocking under the wheel drum so that in case the jack slipped, the axle would not move.

Once the bolt at each hanger was loosened and removed, I inspected the hanger assembly. As you will notice in the photo below, there was significant damage to the OEM 3/16” steel. The actual slot that the bolt rides in was elongated and the edges were being peened over. This reflects the tremendous abuse these hangers absorb during the course of traveling down the road. Couple that with the 12,000 miles for our trip to Alaska, they really took a pounding.

To repair this systemic problem I decided to purchase Lippert’s aftermarket Correct Track II hanger extensions. As you see in later pictures, these extensions were obviously created to address the very issue we experienced.

In order to properly install the new hanger brackets, I modified the OEM hangers by using a grinder with cut wheels to remove the flanges on either side that hold the OEM octagon cam.  When using a grinder or any power equipment I always use proper PPE (personal protective equipment) such as safety glasses, gloves, and in this case, a long sleeve shirt.

Popo took photos of me cutting the flanges off, grinding them smooth and removing the peened or coined edges of the slots.

I cleaned the steel hangers with mineral spirits and alcohol, then repainted the exposed steel with a good heavy duty paint.

I installed the new aftermarket hanger assembly from Lippert on top of the old hangers. Observe in the close up picture of the hanger:   Lippert added a ¼” steel plate to the side. This plate, along with the increased thickness of the hanger, now provides a ½” surface for the new bolts to ride on. Just a little bit more beefy, huh?

In addition to new hangers, I purchased Lippert Never Fail bushings in lieu of the standard brass bushings. In subsequent pictures you will see why.  I also opted to use plain Grade 5 bolts instead of the OEM greased wet bolts because I strongly believe the hollow bolt riding on the steel hanger will wear out over time (like it did previously), cut through, and fail.  And hopefully, the Never Fail bushings require less maintenance.

I aligned the new hangers on either side of the existing hangers and temporarily thru-bolted them together so I could drill a new upper hole for the additional 1/2” bolt.  Extreme care must be taken to ensure the holes align on either side.

Once the holes were drilled, the hangers were removed.   I then placed a spacer tube between the existing hanger extensions in order to keep the hanger from collapsing when I tightened the new bolts up.

After installing the new hanger extensions, I replaced the brass bushing on the leaf spring with the Never Fail bushings.

The last step for each hanger was to install the adjustable octagonal cam. This cam is the basis for the entire Correct Track II design from Lippert. The cam allows for adjustment of the axle by rotating it up to 1” front to back. By design, this aligns the axles with the trailer to ensure proper travel of the wheels to each other. Since I did not notice any unusual wear on the tires nor misalignment while traveling down the highway, I chose to set each cam in the same position at each front and rear location.

Each hanger set up took approximately 2 hours to complete, total of 8 hours for the entire repair procedure.

Once each side was completed, I re-torqued the tires to 130 Ft/Lbs and lowered the trailer jacks so the weight was placed on the tires before re-leveling the coach.

So as you will see from the next pictures, these are the failed or failing components that I removed. Note that the brass bushings, even with the proper greasing of the wet bolts, still failed (which I took into consideration when determining to use Grade 5 bolts and Never Fail bushings).

Careful examination of the wet bolts indicated wearing where they ride on the steel hangers which led to one bolt failing last year and eventually another failure down the road.

Considering that we subject our home on wheels to a 9.0 earthquake each time we take it on the road, these are things that will always take a beating and must be on our inspection list on a more frequent basis.

Wow, writing a blog post is a lot of work. (Really?)  I think I will stick to working on the mechanical things on our home and leave the writing to PoPo!  (An excellent idea, Dad!)


  1. Oh WOW PoPo - be glad Dad had the tools, skills and time to do this! A major project!!! I'm sure most who go to Alaska have a damage report afterwards, glad ours was minimal :)

  2. Nicely done! They look like they took a beating but should be good to go now!