The (DIY) Mechanic ~ Part Two

The 5th wheel tire problem

Once home I discovered abnormal tire wear on the right rear trailer axle. The inside edge of the tire was extremely worn for only having 8,000 miles on it. I suspected that the camber was way out of tolerance on the axles (both front and rear). My little drawing below discribes how camber affects tire wear.

Camber ~ Tire Wear.JPG
How “Camber” affects tire wear

Tire Wear.jpg

Excessive inside tire wear

“Rv.net” ~ To the rescue!

You can bet that someone has run into this problem before and a “Fix” article has been written. Some fixes were horrible, but I found one exceptional detail fix on RV.net on the internet. The internet “Fix” RV.net Fix This article was very, very detailed! It gave me enough info to tackle the job myself. Before I get into the fix, I strongly believe that the reason the trailer axles lose their camber is that of “potholes” especially on some interstates. One of the most egregious that I’ve encountered, is on I-88 from Binghamton to Albany, NY! When traveling at 60 to 65 mph and your 13,000lb camper hits a pothole four or five inches deep, the axle slowly goes from pos to neg camber!

“The Fix”

Why fix it yourself? The answer is simple, there is a Camping World about 45 miles from here, but their answer was simple, replace to axle! Yah, that answer didn’t work for me! After watching several You Tube videos I felt capable of tackling the project myself.

First on the list was the fabrication of tools that I would need to measure camber and also too enable safe jacking or bending of the axle. The measurement tool was a simple matter of cutting a piece of angle iron the lenght of the mounted tire, drilling a couple of holes for bolts that contacted the rim on exactly the same spot a 180º apart. The next step was to take a micrometer and getting each bolt to be the same lenght.

Camber Tool Calibration.jpg

Calibrating both bolts to the same lenght

The measuring tool I used was an angle finder (anolog). I could have bought a digital angle finder, but I felt it wasn’t necessary.

 

The measuring tool completed. It was time to move on to a baseplate for the 12 ton jack. I found a 1/2″ plate exactly the right lenght and width in the shop. From there, I used a bi-metalic hole saw for holes on each end to receive the chains. I had several chians in the shop to choose from. I used a couple of short skidder chains to tie in the axle at both ends. Everything to do this project was available in my shop.

My first attempt to jack the camber back in was not working as planned. You see, I had blocked up the camper literally off the ground. By jacking in this way, the suspension was preventing the “bend”. I blocked the tires to the ground and then the jacking showed immediate response. I kept checking the degree angle gauge. I first started with a “Neg (- 1º)” reading. From my research I needed a  “Pos (+1.5º) I jacked until I had a positive 2º. When I released the jack preesure it spran back to pos +1.5º camber. From this point I took a break from this project. In the future I will verify distance from the hitch pin to axle, from axle to axle. (Another intense project)

That is what I did!

Jacking plate chain slots.jpg

Slotted to hold chain

Base Plate Fabrication.jpg

Jacking  base plate fabrication

Chained for camber Adjustment.jpg

How I secured to axle..Note brake wiring Not pinched

Neg -1 ̊ Camber.jpg

Fabricated angle tool

 

Front Axle  and back axle difference.jpg

You can see the front axle tip out with neg camber, while rear axle sets square on the block!

Final Camber Adjustment.jpg

The final camber adjustment!

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