Hi all,
My 26' class C rv on a 2006 E450 chassis is making this strange rotational sound. The sound gets faster when you accelerate and slows as the vehicle slows, coming to a stop when the vehicle stops. I would not describe it as a howl, whine, or the rat-a-tat-tat of a bad tire. More of a scraping or rubbing sound. Sitting in the driver seat it sounds like it is coming from the front passenger tire area. I have had someone walk along all four wheels and they can't hear anything. I thought it might be a problem with the brakes so I took it to a shop that has done work on our vehicles for decades. The mechanic there said the brakes were shot and so I had them do a complete brake job on the front. Mechanic called me when done and said the sound was gone. I drive the rig 50' and hear the sound. I have him get in and we drive around the block and he agrees the sound is still there. He crawls underneath and checks the driveshaft, u-joints and says everything looks good and feels tight. I then call my local RV repair shop and they said they would not have time to look at it for month, but, said to check the decorative wheel covers, because they often get issues with them getting loose and making a sound like I described. Took them off and the sound was still there. Then took it to a shop that specializes in bigger trucks and vans. I asked them if they could jack up the back end, put it in drive and at least isolate the sound. If there was still a noise it would rule out the front tires and brakes. They call me back and said they fully inspected the driveshaft, U-joints, carrier bearing, differential and found nothing wrong. I asked them if they jacked it up and they said, "no, they couldn't", (why, they wouldn't say), but in their opinion the sound was coming front the front right and that I should take it back to the brake guy and have him thoroughly go over it again. They did say they noticed a little burning smell coming from that wheel, and I noticed it as well when I got home.
So, any ideas what it could be? I also want to just jack up the rig myself before taking it to the brake guy to see if I can isolate the noise. I want to be very safe when doing this. I have seen diagrams where they say to put the jacks (though I will use wooden cribbing) on the axle next to the leaf springs. My plan is to use my 20 ton bottle jack on the frame on one side until I can get the wood blocks in place, and then jack up the other side to do the same. I figure using the cribbing the rig won't topple off in any way, and I don't need to turn the wheels that fast to hear the sound. Any advice on my jacking plan? Thanks.

 

Did the 'complete brake job' include new flex hoses? How far did you drive it home? If that RF brake is heating up, you could have a sticking caliper. I had new rotors and (rebuilt) calipers installed on my E150 and twice had to have a rotor replaced because it was quickly fried by a frozen caliper. The culprit was one of the flex hoses. Old ones can act as a one-way valve and cause a caliper to stick. Luckily, I had it all fixed before I hit some mountains and the extra parts/repairs were covered by the shop.

I would watch that RF very carefully until you find out why it's heating up. A handheld infrared thermometer will help with that.

PS: The shop probably didn't want to jack up the rear because of safety concerns. Murphy's Law. If you do it yourself, pull up with the front bumper up against an immovable object....LOL. For curiosity's sake, call a couple of other shops and ask them if they could do what you're asking.

 

It’s possible its a wheel bearing making the noise too. The unit bearings can make noise even if they are not loose.

 

Sorry about the delay in responding to those who chimed in. I jacked up the rear end of the RV and the noise is still there, (eliminating the problem coming from the front end) and it appears to be coming from the front end of the driveshaft. So will take it to a shop that can do that kind of job. Thanks.