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safe operating brake temps
#1

Super strange question but I had a tire losing some air and when the guys fixed it they told me the brakes were super hot and dragging. So I safely went down the the block to a big rig repair shop and asked if they could check it out after speaking with newell. They checked everything adjusted the shackles and greased the front suspension. All great but I have this strange fear now and bought a temp gun. After driving around the highway and city I stop test the temps and the fronts are around 240-300 depending on the type of driving and rears are 114-140. Am I just freaking my self out because its a new to me rv or is there something I need to seriously  have checked. 1980 newell

1980 38ft "Ole Girl"
6v92
Austin
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#2

I have monitor air and temp in the tires for over 20 years. The best simpilest system is EEZTire-TPMS monitoring system which you can watch all wheel related issues on coach and tow. This has save me many times. It keep you aware of all temps concerning the wheel which cause heat. When you use the brake all temp go up. When you are driving 70 mph temp is hotter than when you are stopped. This is allow you to monitor in real time. I do not drive anything without this assistance.

1996 #422 and 2004 #689 with YELLOW Goldwing, BMW K1200S, RZR, Dodge Truck

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#3

I think you are fine if those are the temps you see with stop and go driving.


If you have one dragging, as I did recently, my temp gun maxed out at 500, so I don’t know how hot it really was. It was hot enough to stink is all I can say. But I do understand the concern, after that incident I was super vigilant for the next 1000 miles.

I don’t know if this is possible for you, but the best test would have you drive 20 or more miles without using the brakes, and use the jakes to coast down as slow as possible before stopping. That would give you the best idea if one were dragging.

Richard and Rhonda Entrekin
99 Newell, 512
Maverick Hybrid Toad
Inverness, FL (when we're home Cool )
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#4

When you checked temps on front :
Was that the temp at the brake drum , or wheel itself ?
Were you doing stop and go , like in urban area ? 
Also , you mentioned the shop adjusted " shackles "  ? Not sure about the brakes on the 1980 , but ours has Rockwell / Meritor brakes which have slack adjusters for the "S cams " which move the brake shoes . Cool truck guys refer to them as "slacks" . When these are adjusted properly there is no contact between shoes and brake drum ( no brake applied  on front ) provided the drum isn't out of round . 
 After replacing front brake drums , shoes , wheel bearings , etc  , I drove about 20 miles on the Interstate . Light braking only on exit ramp with Jake , checked temp , +- 100 . I was mostly checking to make sure the new bearings were set correctly , not building heat . Hub , drum , wheel were all close to the same . Return trip with a little more braking , I saw about 115 degrees . Point being , wheels won't heat up a lot with light or no braking , just the heat generated by the tires .
 I have a new TPMS , but only about 30 miles experience with it so far . 
 Anyway , if you could jack up one front wheel at a time , see if it turns freely .
That would tell you a lot .

1986 #89
VIN 007
Detroit 8V92 TA 475 HP
Allison four speed 
Chris and Sharon Hand
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#5

Yes slack! (I am new to air brakes haha) There was some urban driving at the start then last check was after driving on the highway at around 65 and one stop with mostly jake then slight braking to finish the stop a hold to wait for traffic till we pulled into a parking lost to test. I am also aiming the laser at the drum brake it self. Tuesday I am going to take a longish highway drive and test them again to see how things go and will update on temps. Thank you all for replies.

1980 38ft "Ole Girl"
6v92
Austin
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#6

Based on the driving /braking you were doing , and the disparity between brake drum temps front/rear , it sounds like your front brakes may be dragging . 
There could also be a bearing issue . When I did the brake job on the '86 I found pitting in bearing races and rollers.  Appeared to have fairly fresh grease , I suspect the bearings had been packed and set up with too much preload . In any case,  bearings can be a heat generator if there is a problem. 
Your call , but I would get the front wheels off the ground and get a feel for what's going on. 
Do you have 24.5 wheels ? Not a huge job to remove a wheel and brake drum to have a look. Heavy parts and jacking , cribbing safety imperative. 
Oh , likely left hand lug threads on driver's side !
Chris

1986 #89
VIN 007
Detroit 8V92 TA 475 HP
Allison four speed 
Chris and Sharon Hand
Reply
#7

Also , there are You Tube videos of slack adjuster setting on air brakes . Plus , there is an inspection port on the brake plate . Should have an oblong rubber plug that can be removed allowing visual inspection of brake shoe material and gap between shoe / drum .

1986 #89
VIN 007
Detroit 8V92 TA 475 HP
Allison four speed 
Chris and Sharon Hand
Reply
#8

But if the brakes were dragging wouldn't the temps keep climbing? I did drive for 10 miles and the temps did not go up. they just stayed in the 245 range. Also would there be any other signs of the bearing going bad other than temps in the brake area going up? Should I feel or hear something while driving?

1980 38ft "Ole Girl"
6v92
Austin
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#9

Jack up the axle and turn the wheel by hand. If the brakes are dragging you will feel it.

10 miles on the interstate isn’t enough distance to tell anything. Try 30.

If you do have a bearing starting to go, you may or may not be able to feel it by hand. First indication will be the hub will be the hottest part of the assembly, not the brake drum. It’s simple enough to pull the outer bearing and visually inspect if you suspect the bearing. You will find some general info on bearing inspection in this link.
http://newellgurus.com/showthread.php?tid=5717

Richard and Rhonda Entrekin
99 Newell, 512
Maverick Hybrid Toad
Inverness, FL (when we're home Cool )
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#10

Well ladies and gents the moment we all have been waiting for (well mostly me lol). We took her on a long drive temps were pretty okay. So we bit the bullet and took a weekend trip and guess what! She worked no smells, no smoke and no brake failure. I think it was just my mind freaking me out and the fact that she’s a older rig that needed some exercise (so does the driver).

1980 38ft "Ole Girl"
6v92
Austin
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