RTH traveling, noticed rear brake hub(emergency brakes hat) getting hot (1 Viewer)

[silverhorse]

While traveling, I noticed my rear brake Hub getting extremely hot. In comparison the front is not even warm. Hot enough to only keep your hand on it for a few seconds. The rear E brakes have not been serviced...fyi
Also, rear disc pads are ok.. rear calipers are not hot.. ONLY THE E BRAKE HUB

Thanks gents!

 

[Weedhopper]

Both sides? PB blaster or similar should free it up. Leave the parking brake off after that.

 

[silverhorse]

Yes, both sides... I'm wondering axle bearings? It's strange.. to me the e brake might drag

 

[nwfl4runner]

Yes, both sides... I'm wondering axle bearings? It's strange.. to me the e brake might drag

Was thinking bearing over stuck parking brake

 

[CharlieS]

You could pull off the wheel and dial back the star wheels to eliminate ebrake shoes rubbing as a root cause until you are in a place where you can remove the rotors and examine/service them.

Also, I wonder if a cheap infrared heat gun could be used to narrow down the source of the heat? They've really come down in price in the last decade, and I think you can even get them at places like harbor freight and some large auto parts chains.

 

[Sandroad]

If both sides, I suspect a sticky parking brake linkage. It wouldn’t take too much corrosion or goo to drag the shoes a bit. Sticky place could be under the console behind the hand lever or in the wire/linkage going to the back.

 

[silverhorse]

So just an update... I tore everything down. Everything appears normal.. drum is not dragging , everything looks great..
But that's definitely some excessive Heat going on in there... not sure what to think about it

 

[TeCKis300]

I carry a non-contact thermometer in my trailer. I'll intermittently check the hubs for elevated temps when towing as an easy inspection because of loads. I'm well over rear axle 4300lb GAWR, scaled at 5,460 lbs.

I don't remember exact temps, but the rears didn't stand out as particularly hot. No more so than the other hubs. Memory is fuzzy but most of them were ~130F?

How many miles do you have on the rear bearings? I proactively replaced mine when I re-geared at ~125k but they looked great. Others have found issues in theirs. Maybe get a thermometer. Another easy inspection may be the pull the rear ABS sensor to see if it's clean inside?

 

[silverhorse]

133k on the original axle bearings, but no play when I wiggle the tire

 

[silverhorse]

Are you saying the ABS sensor could cause an issue ?

 

[bloc]

My failing rear bearing had no play but it did make a lot of noise. It was still difficult to pinpoint until I got chassis ears.

You can easily pull the abs sensor to inspect the tip for signs of chafing or brown sludge which is a sign of contamination and possible bearing failure.

Is the paint on the rotor hat intact? IMO not being able to keep your hand on a wheel hub part is nothing to worry about by itself. You need some data (aka actual temperatures) to determine if this is really out of the ordinary.

 

[TeCKis300]

^Good point by @bloc. I wouldn't leap to suggest anything is definitely wrong based on touch. Worth inspecting, but if it were only a single hub standing out as hot, would get more attention. I don't exactly know what's really hot based on touch because I used a thermometer. Maybe 150*F?, which might still be in the norm. I don't recall specific temps other than when I'm inspecting, I'm looking for a temperature that's standing out from the other hubs.

 

[thabruiser]

Just curious, what made you suspect the rear e-brake areas were hotter or abnormally so? I don't usually go around on a trip and start touching my wheels or brake parts unless I smell something hot, or hear the rotor ticking or popping from the heat (a lot like a catalytic converter will make noise after just driving and then turning the vehicle off...). And also, what kind of driving had you just got done doing? Downhill, flatland, towing anything?

 

[TeCKis300]

Did some digging to understand what's normal temp range for hubs. The interwebs seem to suggest 140-175 as in the realm of normal. Those definitely get into temps where they'd be hot to the touch.

 

[silverhorse]

So what made me check it was I smelt a brake, grease smell. You know if you've worked on vehicles for a long time you can smell an issue .. whether it be an engine overheating Etc that's what made me touch the hub.

 

[silverhorse]

Thanks for all the input guys! I'll grab a heat gun and keep you posted

 

[CharlieS]

I've had this one since 2015 and for a $20 spot it's pretty useful: https://a.co/d/ftywGEd

 

[silverhorse]

so here are the temperature numbers. 197° on the rotors,
155 to 165° on the emergency brake Hub part of the rotor...

 

[bloc]

so here are the temperature numbers. 197° on the rotors,
155 to 165° on the emergency brake Hub part of the rotor...

Same on both sides? It would be hard to compare front to rear but side to side should tell you a lot.

My cruiser occasionally makes a burning rubber smell after long highway stretches. I’ve never been able to narrow it down, and it clearly hasn’t led to a wider problem after over 80k miles of ownership.

 

[TeCKis300]

so here are the temperature numbers. 197° on the rotors,
155 to 165° on the emergency brake Hub part of the rotor...

Was this after a quick stop off the freeway? I wouldn't be surprised on the rotor temp if it was a hard stop as that'll put heat into them.

Would love to pull some better brake hub temp numbers for you but I won't be going on the freeway anytime soon as my commute is all local.