Smell and heat from rear wheel wells

arncota · 09-17-2019, 03:53 PM

Hi,

Sometimes after even a 20-30 mile trip I will get a whiff of a weird smell coming out from under the coach. It smells like burning plastic or something. It seems to come from the rear wheel wells. The wheels and tires are warm or hot to the touch. It goes away quickly and I havent noticed any issues with breaking, or any noises. Before I take it in for service, any thoughts on what it could be? We did have ants infesting the insulation and would find little white piles of "dust" under the RV but we have taken care of that with some ant traps. I thought maybe it was plastic burning off from those droppings but it could be brakes or axle I guess?

This is on a 2008 Winnebago Outlook 31C with only 10k miles.

**ThomB** · 09-17-2019, 04:16 PM

My first thought was you sucked up a bag somewhere in there that is getting heated and burning but if it's persistent than that's something else. That something else sounds like maybe it's a bearing issue and you're heating up the hub and burning off grease? That could add to the excessive heat if it's truly excessive.

I think finding out if the heat is normal would be a good thing to see. Does the other side do the same thing? Is it both sides? Are the fronts heated up in the same way?

You're probably doing the right thing getting it in for a service stop.

Topsail · 09-17-2019, 05:09 PM

Both side of the rear? Maybe pick up one of the cheap laser heat guns from the big box stores. Drive some and pull over to take a reading on the hubs. Just a thought.

**Eagle5** · 09-18-2019, 01:09 AM

Sounds like your brake calipers have rusted to the point that the non-piston slide-side is not moving freely. After about eleven years of mostly sitting around, corrosion can build-up.

arncota · 09-18-2019, 07:29 AM

Ok yea its been sitting more than not for its life. I will take it into a shop and get them to check it out. Thank you!

CharlesinGA · 09-21-2019, 08:54 PM

Ford uses phenolic pistons in the brake calipers and this material tends to swell and also collect dust and crud. End result is the pistons stick and do not retract properly, leading to brakes dragging and heating up. I've had it on the front of my Ranger pickup twice, and my coworker has had it happen on the rear of his 3500 Ram pickup twice.

You will probably need to replace all of the calipers to eliminate the problem or the risk of it happening in the future.

Charles

NeilV · 09-23-2019, 07:13 AM

Sounds like brake caliper service is a bit behind. Hydraulic brakes in use on motor homes are considered in Severe Service so regardless of how many miles its driven they need to be flushed and refilled with fresh brake fluid at least once every two years along with have the caliper guides, pins, etc lubricated with a high quality silicone brake caliper grease. That heating is beating up your calipers, rotors and brake pads along with the rear wheel bearings (possibly the differential too) and puts you at risk for a wheel fire.

Note that some ABS pump and valve assemblies will also start sticking causing similar if brake flushes are skipped and the brake fluid absorbs too much water and turns corrosive.

I am not sure when Ford made the switch however in 2001 they were still using Kelsey Hays calipers with the steel pistons and not the troublesome Bosch calipers that plagued Workhorse so badly.

A good practice on any seldom used vehicle with disk brakes is to drive forward and backwards a few times tapping the brakes sharply to stop before changing directions to help free up the calipers, shake off the dust and get them moving again after their long period of inactivity.

Don't wait until it gets bad enough to be noticeable when braking as by then you may already be looking at caliper and rotor replacement instead of just a cleanup with a flush, caliper lube and new brake pads.

Elgann · 09-23-2019, 01:10 PM

I looked in rear view mirror and saw my tire smoking and melting to the side of my little 2 year old winnie drop.

In the middle of nowhere Nebraska.

My wheel bearings went out.

And my water pump just went out.

Is this normal? And is it normal for the tires to be so close to the camper?

arncota · 10-28-2019, 08:41 AM

The issue has been resolved. $1700 and change later. We had a mechanic replace all the rear brake components on both sides. This also included new seals, new brake fluid, etc. He checked the fronts and they were fine so we didnt do anything there. He also checked the tires, put in a new battery, and adjusted the airbags. I drove it 2 hours on Thursday. No smell, no heat, more power, excellent braking.

**Eagle5** · 10-28-2019, 10:04 AM

Excellent report! One must have good brakes, to be sure.
If you are out in the weather when storing your motorhome, it would be good to invest in a set of four wheel covers. I use those, and it keeps the wheels clean and dry.

arncota · 10-28-2019, 10:13 AM

Yes! I winterized and covered the wheels this weekend.