Hub temperature

[Dave in Asheville]

I recently finished installing electric brakes on my 2010 Scamp 13 deluxe. The parts were from etrailer and included new hubs, brakes, bearings and seals. I followed all installation instructions as directed, as far as I know, including working grease into the bearings, adjusting nuts on the axle and adjusting brakes, etc.

Just finished a trip to Charleston, SC, about 280 miles each way. On the return trip it was about 60 degrees F when I left. Drove about 150 miles at 63 mph before stopping. Temp was about 70 and hubs were just warm to touch. Drove home at same speed where temp was about 75 degrees and hubs were too hot to hold on to.

Any thoughts regarding the cause and solution are welcome. Thanks!

[redbarron55]

First jack up the wheels and check each to see if you have a brake dragging.
This will cause the hubs to get hot.
Also if the bearings have been over packed this will make the hubs run hot if the brakes are not dragging.

[John in Michigan]

Dave,

If you mean just the hub portion outside the wheel, that could be overheated bearings, possibly because the retaining nuts are too tight.

I would also touch the brake drums. If the brake drums are even hotter, then the problem is likely that the shoes are dragging and need to be adjusted (loosened).

John

[I had the right brake overheating, and it turned out that it was because the left brake magnet was not engaging the brake. The left brake magnet was hanging loose because the retaining clip had come loose.]

[thrifty bill]

Spend $20 at Harbor Freight and get an infrared temperature gage. Then you can have real data. I bought their little more expensive version with a lazer aim. Cost $28. Should be any campers tool box.

[Spongelander]

If it's not dragging brakes, you may have your axle nut on too tight.
this is the general idea; dexter specifies using 50# of torque. The idea is to take all the slack out of the bearing assembly, then back off the pressure used to take the slack out, then just barely tighten after feeling resistance. If a cotter pin or retainer won't fit, err toward loosening the nut in order to make it fit.
https://www.championtrailers.com/pre...heel-bearings/

[Byron Kinnaman]

Originally Posted by thrifty bill

Spend $20 at Harbor Freight and get an infrared temperature gage. Then you can have real data. I bought their little more expensive version with a lazer aim. Cost $28. Should be any campers tool box.

WARNING Cheap IR thermometers can be very inaccurate in ambient temperatures away from 72°F.



I spent the last years of my career designing IR thermometers that will work in an environment between -40° to 130° F. It was far more difficult than would have gone into a Harbor Frieght IR thermometer. In order make it with ±1°C through out the -40° to +130°F we were taking about 62,000 pieces of data every 3 days then analyzing the data.
It has been estimated that from time we start the project to having a product that those requirements we spent close to $4 million.

[Dave in Asheville]

Thanks for the suggestions! I'll check for brake drag and nut pressure on the bearings.

[WizWid]

Originally Posted by Byron Kinnaman

WARNING Cheap IR thermometers can be very inaccurate in ambient temperatures away from 72°F.



I spent the last years of my career designing IR thermometers that will work in an environment between -40° to 130° F. It was far more difficult than would have gone into a Harbor Frieght IR thermometer. In order make it with ±1°C through out the -40° to +130°F we were taking about 62,000 pieces of data every 3 days then analyzing the data.
It has been estimated that from time we start the project to having a product that those requirements we spent close to $4 million.

But the OP's problem was happening at about 72F. So the cheap thermometers should be fine.......

[Byron Kinnaman]

Originally Posted by widgetwizard

But the OP's problem was happening at about 72F. So the cheap thermometers should be fine.......

One of the biggest mistakes made is trusting cheap instruments.

[Spongelander]

I used to work for Raytek, Incorporated (now part of Fluke) in the early days of IR noncontact thermometers. Ours were quite expensive; some were used by Florida Power and Light to measure transformer temperatures at some distance (from the ground, and from helicopters). Our thermometers had a 3" diameter by 18" aluminum barrel, a rifle stock, and a rifle scope. They cost about $2000 in 1980.

I have one of those cheap IR thermometers. I could compare it to a known temperature source, but haven't bothered. I just want to get a general idea of the temperature - even a 10% error wouldn't bother me, I think, at least for my application (curiosity).

[Raspy]

One of the best kinds of instruments there is, and one we all have, is our hands. Simply touch each hub when you stop for fuel, or for the night, and notice their temps. If they are all about the same temp and not too hot to hold your hand on, they are fine. If one is very hot, there is a problem. That is "real data", where none are too hot, or one is way different than the rest.

After a lot of downhill braking the drums will be too hot to touch, so an infrared thermometer will be useful to see if all the drums are the same. That too, all the same or not, is "real data", more than a specific temp. Accuracy is not as important as consistency. There are no certain yes or no numbers to determine a problem or not. It's the comparison that matters most. This means the thermometer does not have to be certified as accurate, it just has to be consistent and able to measure temps higher than what we use our hands for.

Another sign of a problem is pulling to one side. If one brake is grabbing, or one is not holding as it should, the trailer will pull to one side and this is easily noticed in the TV. You can look for this too, by manually applying the trailer brakes at the controller as you look in the rear view mirror while on dirt or gravel roads. One tire might skid much easier than the rest or not skid at all, as you carefully apply the brakes at a low speed and watch for what happens.

Every time I connect and pull away for the first time, I apply the brakes at the controller to feel for them to apply. This is also good practice for remembering how to apply them in an emergency during uncontrolled sway. I also keep my controller adjusted so that I can feel the trailer hold back slightly every time I put on the TV brakes. This provides an operational check at every stop.

If you are wondering just how much braking is available in your trailer, you can apply the trailer brakes only, on a downhill and notice how long it takes for them to fade. Then on some long downgrades later, you might have a feel for when you should stop and let them cool, before the TV has to do all the stopping and it's brakes over heat too. This is a situation where a diesel engine brake is very nice to have, as often, the truck will hold back without using the brakes at all.

[Kenny in Ohio]

Dave,
When checking the bearing temp while traveling as you said you had good temp the first time after about 150 miles but second check it was hot. I've done the same thing. If you slow down and check be sure not to use the brakes too much, extended use of the breaks will elevate the temperature, so if you were close to home in stop and go traffic it is likely your problem. Take it out again, run at normal traveling speed and come to a stop where your not aggressive on the brake and see how that is. Then you know for sure.

[LyleB]

Not discounting any of the advice given above, I just thought I'd point out the following. I had a new axle installed on my 13 foot Scamp shortly after buying it. I was new to trailers. The hubs were running what to me seemed hot. Not that I couldn't touch them, but it was uncomfortable to hold my hand on them for more than a couple of seconds. I took the trailer back to the local shop who installed the axle, they checked and said all was well.

I took the trailer from Mich to North Dakota, stopping at Backus on the way for some unrelated work. While there I asked about the temp and the fact that the hubs were spewing grease when they got warm. The Scamp mechanic checked and said the bearings were over filled and the excess grease was just working it's way out and into the dust cap. He cleaned out the dust cap and said I may have to do this again. Otherwise he said that sometimes new axles run hotter than normal until the bearings "seat". Not to worry about it.

Well I had this trailer for several years, and as advised, the grease spewing and the increased temperature both resolved themselves after a few more hundred miles. No further problems in the next 3 years.

[redbarron55]

Too much grease WILL make the bearings run hot as well as the possibility that the high heat will cook the oil out of the grease and you will be left with a cake of soap and clay instead of grease with a damaged bearing inside.
A bearing (if hand packed) should be packed no more than 1/3 full so that when the bearing turns the excess will be pushed out of the race and end up in a ring around the bearing.
Personally I like the EZ Lube that will let the excess grease be expelled to prevent this problem.
Your hand is a pretty good judge of the condition of the bearings and hubs along with tires.
If you pull off in a rest area and don't particularly use the brakes you should have hubs that are warm to the touch and tires slightly warmer.
New synthetic greases are able to withstand higher heat, but never mix the Synthetic and old style grease as the combination will cause the oil to separate from the base soaps and clay.

[Paul O.]

Originally Posted by Raspy

...

If you are wondering just how much braking is available in your trailer, you can apply the trailer brakes only, on a downhill and notice how long it takes for them to fade. Then on some long downgrades later, you might have a feel for when you should stop and let them cool, before the TV has to do all the stopping and it's brakes over heat too. This is a situation where a diesel engine brake is very nice to have, as often, the truck will hold back without using the brakes at all.

Excellent post, Raspy, especially the part about engine braking. I have towed a number of times over the Colorado and other mountains and always stay in low gear descending and take it easy. It works just as well with gas engines, like mine. There are dozens of signs on I70 and CR285 reminding the truckers (and the rest) to downshift and stay in low gear. They go like this: "TRUCKERS, DO NOT BE FOOLED, YOU ARE NOT DOWN YET! MILES OF STEEP GRADES AND TIGHT TURNS AHEAD! STAY IN LOW GEAR."
And, over time, I have seen a few trucks with their brakes smoking and smelled the burning phenolic...