Keep an eye on those trailer bearings

Nice and shiny after a clean up: the front bearing, washer and nut. The bearing is now ready for some more grease to be applied to it.

by Wayne Kampe •

Boat and camper trailer owners soon understand that few things will willingly repay neglect nor will the wheel bearings, those unseen little heroes that carry the full load of whatever’s above the axle. And at whatever speed is involved! This understanding is easily reinforced by the all-too-familiar sight of a boat trailer on the side of the road – sometimes with a big scrape on the road leading to an absent wheel – as the result of a bearing failure.

To complete the scene the axle will usually have a jack under it with some member of the party standing guard while the rest of the team have driven off to see if they can round up some assistance or maybe spare parts if there’s knowledge of what’s required to fix the problem.

Camper trailers (and of course caravans) don’t suffer so much as boat trailers do, because they are not subject to immersion in water to any great extent. Boat trailers backed into salt water on a regular basis are well and truly in the firing line. This means that the smart boat owner will see the need to check on things from time to time. The more it’s used in salt water, the more often you need to assess the bearings and possibly re-grease them as preventative maintenance.

I look at my boat trailer bearings every three months when the boat is having regular use and in over two decades I have only experienced one issue when bearings on one wheel were growling, although still functioning. Growling? Yes, a bearing that’s suffering corrosion or pitting will usually emit some noise when the wheel is elevated from ground contact and spun, so this is the first step in a bearing health check up. With the wheel spinning there should be no grumbles, growls or other noise other than a slight whir.

New grease and nitrile gloves are important items for servicing wheel bearings.
With the Bearing Buddy removed and some excess grease cleared away, the split pin and castellated nut are accessible.
Out comes the split pin.
The castellated nut and washer have been removed and the outer bearing’s being slid out along the spindle by gently drawing the wheel outwards.
The residual grease within the hub of the author’s camper wheel shows no signs of contamination, just a little discolouration from use.
Note the machined step at the rear of the axle spindle. It’s this step that the rear bearing seal butts against.

The next step is to take hold of the wheel on each outer side and check it for bearing free play by pulling and pushing it from side to side – gently, that is; don’t dislodge the trailer from the car jack! If there’s play noted the bearings might need to be tightened, but more on this later.

For the record there is no great mechanical expertise involved in checking trailer wheel bearings. Even doing a periodic regrease is pretty much a DIY project that is fairly easily mastered. If you don’t feel you are up to the task or don’t want to muck around with grease, it’s wise to ensure bearings are checked – or even replaced – professionally from time to time.

I would stress that the steps I am outlining in this article are not necessarily going to ensure total bearing efficiency or longevity, but are certainly worth considering if you like keeping in touch with the boat/camper’s running gear on a preventative maintenance basis.

Our trailers have two sets of bearings; an inner set near the rear seal on the axle plus another (smaller) up front which is set just behind the Bearing Buddy or dust cap, depending upon which of these is fitted. Both bearing races with their tapered rollers within them sit within a very close fitting hardened cup or slipper which is push-fitted into the wheel hub and it’s within these cups that the bearings rotate. Note that common bearing components are usually of Ford or Holden origin on smaller trailers.

As the bearing sets are actually several centimetres apart – and the wheel is rotating around the axle courtesy of the bearings – there’s ample room for grease to be applied around the axle to firstly assist in reducing friction within the bearings and to keep out as much water as possible.

Providing the rear seal’s in good condition and the front cap or Bearing Buddy is properly fitted, both these items will also deter water entry. It can still sneak in if there’s unforseen prolonged immersion, hence my view that plenty of grease around bearings makes sense.

Tools for a bearing check up are a car jack, large shifting spanner, screw driver for prying things, and a pair of multi grips for extracting a split pin. Nitrile gloves, a tub of grease, some old paper, plenty of rags and away we go!

Camper trailer checked

Note that the series of images here are taken from one of the wheels of my Trek camper trailer as it’s due for some five-hour Macintyre River visits this month and has not been checked for six months according to my records.

The first step was to jack up a handy wheel and give it a spin. The result was very pleasing: just a slight whir, as expected. A bit of a push/pull on each side revealed no slack, so things were looking good. I love to be sure rather than sorry, so I kept on with the inspection after placing a few sheets of newspaper down beside the wheel to collect components as they came to hand.

The components consisted of Bearing Buddies, a split pin holding a large castellated nut in position to lock the outer bearing in place, plus a big washer that sits between the castellated nut and the bearing race. Naturally, there is going to be a fair bit of grease about the place, but more on this later.

First move (with the wheel elevated of course) was to gently knock the Bearing Buddy from side to side to loosen the Buddy and removed it. If you have a rubber hammer there’s a job for it here.

There was a fair amount of grease that had been pumped in through the Buddy’s nipple on the outer section of the castellated nut and once this grease was removed it was easy to straighten ends of the split pin holding the all-important castellated nut in place and remove said pin from it’s dedicated hole in the axle with multi grips.

Working on the outer bearing

The outer bearing was now quite accessible and a gentle tug on the wheel saw the bearing slide out along the axle spindle for a clean up and to be assessed. At this point the grease was also assessed. I saw it as merely a bit discoloured from use and with no traces of water (creamy residue) about it. Mere darkening of the grease is no biggy, but if there seems to be water in it, a very hard look at the bearings should take place.

It’s best to assess your bearings after a solvent has removed all grease. Petrol is as good a solvent as anything, but the clean up needs to be carried out within a metal container or other non-plastic container, which said petrol might dissolve. When the bearings have had a good dunking and cleaned up with an old tooth brush all surfaces can then be assessed for any pitting, or distortion of the cage they sit in. After thoroughly allowing them to dry it’s easy to give them a spin to see all the old grease has been dissolved and the petrol’s evaporated. And so long as the bearings are totally shiny, not pitted, and the cup within the hub is also as clean and unmarked, there’s no reason not to regrease and replace them.

In next month’s issue I will tackle greasing and reassembly of the outer bearings and discuss what’s involved in taking a look at rear bearings as well. It’s wise to ensure you can access more parts if required by working on bearings when supply outlets (Repco, Super Cheap, etc.) are open.