Trailer is 20' enclosed with 4-wheel electric, 10" drum brakes. Getting ready for a trip I noticed my front hubs were hotter than my rears after a drive. Rears were barely warm while the fronts were pretty darn hot...couldn't leave my hand on for more than a few seconds. One rear brake as been removed as it was trashed and I think the other rear is worthless...need to replace all 4 but that's another time. Thus I believe is my temp difference between rear & front hubs.

However I decided to do a bearing replace and repack on the front hubs. Got it all done and went for a test drive and still the same result. All wheels spin freely by hand and don't make any noise save for a bit of drag from the magnet or shoes.

The castle nut was pre-loaded then backed off a 1/4 turn before locking out the retainer tab. There is next to any play in the drum. All hubs have plenty of grease via the repack and the zerk fitting after a 25 mile test drive.

Got out the IR thermometer and the rear hubs are ~110 while the fronts are ~145-155. Does this sound typical for drum brakes/hubs? What is the danger zone for the hub/bearing with drum brakes?

I'm getting ready to haul 600 miles round trip for a 4-day weekend so just trying to make sure all is ok.

 

Atypical, normally all hubs will be about the same temp. Mine vary by less than 5 degrees.
No preload on taper bearings. In general up to 50 lb/ft, then back off without turning your wheel so nut is free and retighten finger tight. You should be barely able to feel some play when your are done.

Steve

 

You could try disconnecting or disabling the trailer brakes and recheck.

I've not checked with my IR, but the front hubs without brakes on my car trailer are always noticeably cooler than the rears with the brakes.

Horse trailer is the same way. Brake axle hubs are always hotter than the non brake axle.

 

I talked to the tech at the trailer place where I buy all my parts and he said my scenario is perfectly normal....150* is nothing to worry about. He's seen them run fine at 300+. The grease they use every day (which I used as well) is rated for normal use up to 350F with a drop point of 500.

My mind is at ease for this last, short trip of the year. I'll just keep the IR gun handy at fuel and bathroom stops. I'll get (4) new brake assemblies and get everything squared away this fall for next season.

 

I agree the temperatures you are seeing is not an issue. The curiosity is the difference in hub temperatures unless it is an issue of brakes versus no brakes.

Steve

 

I had new bearings and brakes replaced on my boat trailer, the manufacture says that 200* is typical temperature.

 

There are so many factors that affect bearing temperature it is hard to what is wrong or right until things get really hot. All four of mine run within 2 degrees of 115, after I have run 100 miles. Others have reported higher temperatures and some report lower.

As general rule, a better marker of potential problems is how close they are together in temperature and what your normal baseline is. For example, if I had one wheel suddenly run a lot hotter than the others, I would take notice. I think that is more significant than if they all ran a bit hotter one time and cooler the next. Although, if several of mine started running hotter at the same time, I would be thinking it is time to break them down and lube them.

Steve

 

just to add,, the side that faces the SUN maybe 20 to 30 degrees hotter... then the side that is in the shade .. going down the road.

and mine.. mostly are 30 degrees above air temperature.. with the sun side 20 more.

so air being 70,,, shade side is 90, and sun side being 110. but this is an average.

and a good grease can handle 300 ..