Bearing temperature

fisherkb · Posted: Mon May 20, 2013 8:43 pm Post subject: Bearing temperature

All,

I realize that this has been covered before but it is still a bit confusing to me. I am wondering about the proper hub temperature when towing. I repacked my bearing and recently did a short tow of about 70 miles. I have surge drum brakes and a tandem axle trailer for my 22 cruiser. The route contained a lot of hills (the whole way mostly) and the temperature was 95 degrees (the IR said the black top was 135 degrees in the sun). My coolest hub was 107 degrees (on the shady side on the trip without brakes) while the hottest hub was 150 degrees (sun side and the axle with the drum brakes). I realize this isn't in the "danger zone" of 200+ degrees but I am wondering whether I need to recheck the tightness before I embark on a longer term this summer. People quote good operating temperatures but they don't seem to account for the ambient temperature. Some say it is bad if it is too hot to touch but honestly anything metal in sun is too hot to touch in the summer here in Texas....

Any thoughts appreciated.

Karl

Sunbeam · Posted: Mon May 20, 2013 10:00 pm Post subject:

I have a tandem trailer for my 22. Disc brakes on both axles (these supposedly cause the hubs to run hotter than drums, or at least so I've been told) with 13" wheels. Once I got things sorted out (from when the pros worked on it Wink

) my hubs have been running around 80º-105º F with ambient temps of around 50º-70º (not that I wrote the ambient temps down, but I was traveling Washington-California-Arizona-Texas in December, and then back to Arizona in April so I think I at least have it close).

Before I "re-worked" the shop's work, I was running in the high 170º or more range - seemed way too hot and I was fairly certain something was wrong. Indeed, the temps came right down after I fixed things up. I found several problems, including castle nuts that were much too tight, and brake pads that were improperly installed and dragging on the hubs and/or jamming crookedly in place (had to replace the latter set of pads). Also the brakes were not releasing properly due to a brake hose that had been bent at a sharp 90º angle and a faulty actuator (other than that all the work was fine Wink

)

The temps were measured by IR thermometer on the hubs. I don't know exactly how things are supposed to be, but this is what I have observed.

Sunbeam Hot

Chester · Posted: Mon May 20, 2013 10:02 pm Post subject:

At the very least jack the warm side up and give the wheel a spin.

sportner · Posted: Tue May 21, 2013 10:30 am Post subject:

We run at 80˚-105˚ with 10-11,000 lbs. on a two axle trailer.

Will-C · Posted: Tue May 21, 2013 11:02 am Post subject: Bearing temperature

Jack up the wheel and see if you can feel any play in the bearing. It should not be much but you should be able to feel it. Loose is better than tight. We usually back off a quarter turn after hand tightening the nut as a starting point and then check for play. Another thing to look for is to make sure the surge brakes actuator master cylinder is not causing the brakes to drag due to rust in the fluid. Keeping brake fluid changed and bleeding the brakes every two or three years is a good idea to insure the system stays free of water which causes corrosion as brake fluid attracts water.
D.D.