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Dragging disc brakes for dummies
#1

Like to try to post stuff I go through so that it may help others who are also new on their journey.  Had my Pressure Pro TPMS put on late summer and just love it.  Noticed last time out that after about 30 minutes of driving I had and inner drive tire gaining about 5 pounds and it was not in the sun, etc.  By the time I got back in another 30 minutes it had went up a few more pounds and both it and the outer drive tire showed higher temps than all other tires.  Checked hub temps with IR gun and sure enough that hub was 30 degrees higher than all others.  Knew I had a problem, but wasn't sure what it was and I had an air leak to tend to so I put the coach back in the shed, addressed the air leak and then attempted to figure this out a couple weeks later.

Figured maybe I could feel it dragging so I first tried to get up to about 5 MPH and coast in neutral, didn't notice anything.  Jacked up that side and spun wheel by hand and while maybe it felt like there was a little friction these novice hands didn't know.  Figured I'd jack up the other side to see how easily they spun and it's possible to say maybe it was easier to spin the other side, but it was so slight maybe it was in my head.  But I figured it wasn't like it was hung up in significantly so I figured I'd go for another short drive and check temps.

Same exact thing.  Temps go up on TPMS, pressure increased due to temps.  After discussing issue with a fellow guru I realized what I needed to do was us my IR gun to shoot brake rotor temps to see if it's actually the brakes. Super easy to check as you could just shoot it from the other side of the coach.  Sure enough rotor temp was about 175 from purely highway driving on bad side and good side is about 75 degrees.  

So what did I learn?

1.) Checking hub temps matters.
2.) TPMS can be a helpful tool more than just a tire going down.
3.) You can't tell if a brake is dragging mildly by spinning wheel.
4.) If you suspect something is getting hot and you think it might be the brakes, check the temp on the rotor so you know if it's do not pass go hot or dragging slightly like mine is so I can still drive it down to the shop I use to fix it.  Hub temp was my first notice, but should have checked rotor temp immediately.

Funny how it all seems so logical AFTER you figure it out.

Brad Aden
2003 Newell #653 Quad Slide Cat C-12 engine
Towing 2020 Grand Cherokee Summit
St. Louis, MO
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#2

Brad, my Foretravel has Meritor brand disc brakes. Original installation at Foretravel factory does not include Meritor brand helper springs. I had them installed on each slide pin, 2 per brake, on my now sold 1995 and now installed on my 2001. Both coaches went years with no helper springs but totally wore out pads on one or two axles indicate dragging. Would not go without them.

If you do not have Meritor brand brakes, this may not apply.

Rudy Legett
2003 Foretravel U320 4010
ISM11 450 hp Allison 4000R
Factory Authorized Aqua Hot Repair Center
Southeast Texas Area
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#3

Good catch Brad, we bought the pressure pro also and this is our first trip with it and it had me a little gun shy as we where on 40 outside of Memphis and had to turn onto a side road, at the stop light I got a beeping noise and a little red flashing light that said leaking tire but all the gauges read good, a few miles down the road it went out. I guess the cooling of the tire in question caused the leaking light to come on then after we started rolling it heated back up, I had them all 97-100psi cold.

1999 45'  #504 "Magnolia"
Gravette, Arkansas
1996 40 XL Prevost Marathon 
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#4

(01-17-2023, 04:08 AM)Jack Houpe Wrote:  Good catch Brad, we bought the pressure pro also and this is our first trip with it and it had me a little gun shy as we where on 40 outside of Memphis and had to turn onto a side road, at the stop light I got a beeping noise and a little red flashing light that said leaking tire but all the gauges read good, a few miles down the road it went out. I guess the cooling of the tire in question caused the leaking light to come on then after we started rolling it heated back up, I had them all 97-100psi cold.

They make a great product for sure.  Your post reminds me that I need to double check my settings to make sure I have appropriate alerts set for low pressure and I wouldn't mid it if it caught high temp issue like i just experienced.  I'm using the product that just uses your phone/tablet to monitor.  I think I'm going to mount my phone and then figure out how to not have it go to sleep so I can always just glance at it.

(01-16-2023, 03:43 PM)Trainer Wrote:  If you do not have Meritor brand brakes, this may not apply.

I think I have Knorr Bremse.

Brad Aden
2003 Newell #653 Quad Slide Cat C-12 engine
Towing 2020 Grand Cherokee Summit
St. Louis, MO
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