Unidentified wheel noise

[Steph and Dud B]

On or way to OTT in April we had 2 occasions of very loud metallic squealing while braking, both after overnights in campgrounds. The first time, we pulled over into a parking lot and Stephanie walked next to the trailer while I drove circles to identify the wheel. It was the left front wheel. Seemed to only do it while turning in left circles. While doing this she heard a loud "ping!" and the noise stopped. We chalked it up to a pebble in the brake drum. It happened again on that trip, briefly after another overnight on gravel roads, but resolved itself before I could pull over. These were loud metallic scraping noises. We had OTT pull the wheel and no damage was found.

Fast forward to the past 2 weeks. Twice at low speeds I thought I heard noise from the trailer, like something dragging in a wheel, but it would stop before we could check it out. We put 6 hours of highway driving on and the wheels ran cool based on IR scans of the drums. Happened again yesterday, and this time Steph was able to get out and hear it. Same wheel as before, this time a light metallic scraping and not while braking. Not nearly as loud as the previous incidents, either. More like a brake dragging, but again, wheel drum was cool after an hour of highway travel. And once again, she heard a "ping" and it stopped. Quiet now.

I'm at a loss. At the moment it's in a campground so I can't pull the wheel. Aside from the OTT inspection in April I had the wheels off at a good service center twice last summer, once for the Dexter recall, and once to have the brakes and bearings checked after the recall work. There has never been a problem identified.

These are 1 year old NevRLube bearings and the noise is very intermittent so I'm thinking maybe a brake is intermittently hanging up (and the pings Steph heard were it releasing?), but I'd expect to see a temperature difference on that wheel if that were the case. The trailer is currently in a campground because our yard is inaccessible due to construction. Our next move is supposed to be another 3 hour drive. Can't get into a service center before then. If it makes noise when we pull out of this campground I'll scrub the next trip and bring it home (1 hour, mostly secondary roads). But what if it's quiet again? Should I cancel anyway? We've put 3000 miles on it since the first incident last April and there have been no other symptoms besides these 5 isolated noises. I can get to a service center after this next trip. Can it wait until then?

[Steph and Dud B]

P.S.: These are Dexter auto-adjusting brakes, so I can't back it off.

[Steph and Dud B]

P.P.S.: Putting this in writing is helping me process my thoughts. The noise I sometimes hear now from the driver's seat reminds me of the sound manual brakes make when you adjust them until they lightly scrape on the drum. (Unfortunately, I haven't been able to stand next to the trailer while it's happening and Stephanie is less adept at recognizing and describing mechanical noises. If it happens again I need to find a place to get her in the driver's seat so I can hear it myself.) If I'm right, this may be a case of the auto-adjuster making that brake just a little too tight when it clicks up a notch, causing that shoe to drag just a little. On the highway, I'd never hear it and the light drag probably wouldn't heat the drum enough for my TPMS to detect. But it if it happens at low speed I could hear it with the window open.

That makes some sense, but it doesn't explain why Steph says it goes "ping" and stops. Unless Steph was hearing the brakes engage as I stopped the vehicle? That would stop the dragging noise. And then when I release the brake it reseats or frees up just enough to stop dragging?

Can someone check my logic here? (I really don't like these auto-adjust brakes...)

[John E Davies]

You can back off on the Auto Adjust brake adjuster arms, you inset a long thin screwdriver into the oval opening and lift the arm up, then adjust the star wheel.with a brake adjuster tool or flat blade screwdriver.

 

I do NOT recommend this !!  The steel cable that attaches to the arm can possibly lift off of the pulley groove , since there is no retainer to keep it in place. If the cable gets off the pulley the adjuster will no longer operate, and there could be weird dragging noises. I am not saying this is your problem, but it is a very good possibility, especially if a tech did it in an attempt to fix it. These brakes come with no lubricant in the adjuster pulley shaft or the upper attach point, they can and will bind!

https://olivertraveltrailers.com/forums/topic/2778-brakes-auto-adjust-vs-manual-adjust-what-are-the-differences/

There are soooo many bad design flaws in these brakes, the only solution is to put manual ones on, adjust them to about 6 or 8 clicks from binding, and check them every 3000 miles. Or install disk brakes.

John Davies

Spokane WA

[Steph and Dud B]

Thanks, John, I was hoping you'd see this. I've pretty much convinced myself this is a problem with that auto-adjust brake. I don't think a tech slipped the cable because they took the drum off for service each time rather than trying to adjust from the back and they were only supposed to inspect for damage. None of them mentioned adjusting the mechanism. In fact, one of them told me you can't adjust them because they'll just go right back to where they started, based on the cable length.

So, based on the premise that the brake is dragging that leaves 3 questions:

1. Why isn't it running hot? Theory #1: it's only dragging very lightly. Theory #2: it's intermittent.

2. Why is it intermittent? Theory: it only happens after the auto-adjuster increments the star wheel a notch.

3. Why does it stop quickly and suddenly? This one's a little more confusing to me. Theory: after it happens, subsequent brake use retensions the adjuster cable or mechanism enough to clear the shoes off the drum surface.

If those theories are correct I will consider this more of a chronic problem than a crisis and go on with my next trip. Will look for excessive shoe wear on my next inspection and consider future brake replacement. What a pain...

[Steph and Dud B]

This mystery has been solved. A tech removed a loose nut from inside the offending wheel drum today. It was a brake backing plate nut, but all the nuts were in place as they should be, so it must have been an extra dropped into the wheel assembly at the Dexter factory. It was intermittent and wasn't found sooner because it would stick to the brake magnet and hide.