Brake Magnet Scraping Drum/Hub

[Lloydrb]

I replaced bearings this week, all looked good, and saw that the magnets were wearing and marking up the drum/hub (which is it?). The pads are still good. There are about 11k miles on the camper and I have never noticed an issue with the brakes. Camper is a 2020 31MB. I hope there is no issue starting a new thread. If so I apologize. Thanks for any info or advice.

[llr2800]

When activated the magnets drag on the drum to activate the brakes, at some point they do need to be replaced but I doubt it on a 2020, unless one is way worse then the others which would indicate a problem

[Steven@147]

I replaced bearings this week, all looked good, and saw that the magnets were wearing and marking up the drum/hub (which is it?). The pads are still good. There are about 11k miles on the camper and I have never noticed an issue with the brakes. Camper is a 2020 31MB. I hope there is no issue starting a new thread. If so I apologize. Thanks for any info or advice.

Trivia - With shoe type brakes, typically refer to them as just that, Brake Drum and brake shoes. In the case of disc brakes, typically referred to as a rotor or hub. Some disc brake systems the rotor and hub are separate pieces, on others the rotor and hub are a single piece. With disc's you have a brake caliper that contains the brake pads.

Anyway with trailer drum brakes the magnet (suspended on a spring) is supposed to drag on the inner face of the brake drum when activated. At some point the magnet will ware down and has to be replaced, that could be a lot of miles down the road. The inner face of the brake drum will have lots of deep scratches on it, metal to metal contact between the magnet and drum will do that. The brake shoes and brake magnet will ware out a lot faster than the steel drum.
When the brake shoes need to be replaced because they are worn down, Its best / easier to replace the complete brake assembly by just bolting on a new complete brake assembly backing plate. You can order a complete brake assembly (self adjusting or manual adjusting) from a lot of places like e-trailer based on the weight rating of the axle. Example - 7000# axles have a specific drum brake assembly that fits it.
4 or 5 nuts, splice two wires and your done. By doing it this way you also are replacing the magnet. The brake drum itself can last for miles and miles before it needs replaced.

On time when I was repacking bearings I found our right front brake assembly was completely destroyed. The brake shoe material was completely wore off down to the metal shoes, the magnet was tore up and the brake drum had deep gouges in it. Something had come apart in the brakes and just tore everything up. I ordered a new Dexter self adjusting brake assembly and Dexter brake drum complete with bearings and seal from e-trailer, had it fixed in no time. Now I carry spare complete brake assemblies.

[Lloydrb]

llr2800 & Steven@147 thank you for your response. It kinda sucks that I’ll have to replace the drums by the time I swap out the brake assembly. I would have thought the drum would last for years as long I kept good shoes on it. Thanks again.

[Hoopy Frood]

llr2800 & Steven@147 thank you for your response. It kinda sucks that I’ll have to replace the drums by the time I swap out the brake assembly. I would have thought the drum would last for years as long I kept good shoes on it. Thanks again.

They will. Our last toyhauler had about 20,000 miles and 10 years on it with the original brakes, shoes, and such. The one before that was about the same with original brakes. The OEM brakes have very thin material on the shoes, but they do last a long time. Like any brakes, it depends on how much stop-and-go driving you do.

[dryfly]

I was recently surprised to find that the drums can not be "turned" to smooth out the area where the magnet drags. I knew you could turn the surface where the shoes make contact and re-use the drum, so just assumed the inner vertical surface could also be refinished. Wrong!

$15 locally to turn a drum, $150 for a new drum/hub assembly.

[Grandesigner]

Since this is the latest thread on this topic, I'll join in here.
Last year, one left brake was locking up. Turned out the magnet arm came loose and damaged the drum. Replaced under GD warranty.
Today, doing bearing repacks, I found the right rear magnet arm just about to come loose with no drum damage yet. Since dexter has a 5 year warranty and the GD warranty is expired, I was hoping I could get it repaired under dexter warranty. Does that sound like a good plan or should deal with it myself instead of taking it in to the place that fixed it last year?
Also, about half the wet bolts won't take grease. Is that warrantable also?

[jkwilson]

Since this is the latest thread on this topic, I'll join in here.
Last year, one left brake was locking up. Turned out the magnet arm came loose and damaged the drum. Replaced under GD warranty.
Today, doing bearing repacks, I found the right rear magnet arm just about to come loose with no drum damage yet. Since dexter has a 5 year warranty and the GD warranty is expired, I was hoping I could get it repaired under dexter warranty. Does that sound like a good plan or should deal with it myself instead of taking it in to the place that fixed it last year?
Also, about half the wet bolts won't take grease. Is that warrantable also?

Contact Dexter directly and see if they’ll send you the parts.

[uwskier]

Since this is the latest thread on this topic, I'll join in here.
Last year, one left brake was locking up. Turned out the magnet arm came loose and damaged the drum. Replaced under GD warranty.
Today, doing bearing repacks, I found the right rear magnet arm just about to come loose with no drum damage yet. Since dexter has a 5 year warranty and the GD warranty is expired, I was hoping I could get it repaired under dexter warranty. Does that sound like a good plan or should deal with it myself instead of taking it in to the place that fixed it last year?
Also, about half the wet bolts won't take grease. Is that warrantable also?

I'd contact Dexter. When I had an issue with a brake on my new 2022 Imagine, I found the best luck by far was working with the Lippert Chassis Group. They were outstanding to work with. I've heard Dexter is also a solid outfit though I've had no personal experience.

[Grandesigner]

I'm just not sure exactly which parts I need. Here are some pix of the wallowed-out hole next to a good one.