Repairing trailer axle spindle damage

Monday, November 1, 2010

'Tightening' the bearing in place with metal compound is the answer if you are worried about spindle wear on your trailer axle

by KEITH BERGLIND

Trailer axles seem to have a problem with spindle wear that is not normally seen in cars and trucks. The problem is that the inner race of the inner wheel bearing turns on the spindle and slowly wears back and into the face of the spindle.

I first noticed this while servicing RV trailers, including big fifth wheels. One big trailer I had was wearing so quickly that I would check and sometimes adjust the increasing clearance half way through our trip back to Canada from California.

Eventually one spindle had about 1/16-inch face wear. This really wasn't a problem because the wheel bearings still worked. The bearing was obviously turning on the spindle only a small amount. Of the four wheels, this one was unacceptable, two had moderate wear and the fourth never wore enough to feel extra clearance.

The wear is diagnosed by detecting the extra clearance at the wheel. I would just jack up each axle end and wiggle the tire. I knew what they were like after being adjusted, so it was easy to detect if one wheel had new free-play.

Now, if this happened in mid-trip, on the road, I would just pull the dust cap and tighten the adjusting nut. The actual servicing could take place at home. Problem solved.

I decided that the bearings did not appear to have a tight fit on the spindle, such as cars and trucks use. Also, the face contact of the bearing back against the spindle face was not very wide.

I surmised that the bearing was actually wobbling and fretting against the face under the load of the trailer. This I could correct or at least improve upon.

This was a good place to use one of the liquid metal compounds on the market. Typical of this is Thortex, Loctite Quick Metal and even JB Weld. These are usually two-part compounds that we mix and stir together, then use to fill a gap or retain things, like loose ball bearings.

It only takes a small amount of compound to fill the space behind the bearing race; it is important to follow the cleaning instructions for the compound. Then just place enough material on the spindle to fill the gap. Turn the bearing against the compound until you feel it touch the spindle space.

Now remove the bearing and clean the race. Lightly touch the bearing with oil. This will stop the compound from sticking to the race. After all, you may want to change it some day. It is a good idea now to install the hub and bearings tightly, and allow the compound to harden overnight. Next day, adjust the proper bearing clearance.

I've never had a repeat wear problem with this repair. BF

Keith Berglind is a licensed heavy-duty mechanic