Electro Magnetic Brakes

[marine6805]

I’m a little confused. The magnets are soft compared to the drums. Copper and plastic mostly. I’ve worked on a lot of trailer brakes and never seen the magnets damage the drums. There has to be something else going on.

I guess my (then) 3 year old (27K miles) trailer was an anomaly . . . .the magnets had severely gouged the drums.

 

[jkwilson]

I guess my (then) 3 year old (27K miles) trailer was an anomaly . . . .the magnets had severely gouged the drums.

Apparently so. My 1989 utility trailer is on its third set of magnets and the drums are still original with no issues. When it’s loaded,it’s usually overloaded with hay.

 

[Wichita Dave]

@KSCCM10 Sounds like your brake shoes are not adjusted correctly (to much gap between shoe and drum).

The best online education source I've found is The TrailerSmith (a shop in Decatur, Texas), they have several videos about brake operation, diagnostics and maintenance.

 

[Steven@147]

Just wanted to comment, the brake magnets shouldn't be deep gouging the the drums inside face. The magnet should just clamp with electrical power to the drum inside face and slide on the face surface thus actuating the fulcrum arm spreading the brake shoes to contact the drum.

If the drum face is getting deep gouges it seems something is wrong. Hard chunks of something is getting caught between the magnets and the drum face causing the deep gouges.
Maybe the magnets are coming apart. Could be chunks of the brake magnets are falling off and gouging the drum face. I think I would inspect the brake magnets carefully. Along with the springs on the magnets. They should look like a person took very coarse sandpaper to them with no gouges or chunks missing, same with the drum face.

The magnets themselves have what look like two steele lines embedded in them in the middle of the magnet, kind of like this ll. The rest of the magnet is just like a pad material similar to what a brake shoe has. The magnets should also have springs on them to pull the magnets back when power is cut off. Maybe the springs are falling out and getting caught between the magnets and the drum inside face.

Additionally RAM trucks IBC software decreases brake output below 10 mph. So a lot of owners set the gain way too high when initially pull testing the trailer brakes when taking off. To owners it feels like there isn't enough brakes so they turn up the gain way up. The truck is barely moving so the brake output is halved by the IBC (integrated brake controller) . There is a very good discussion on the RAM Heavy Duty Forum, find it here.

Brake Controller Troubleshooting/Technical Info

This post is about the brake controller on the 2021 HD Ram. First, my story. Second some reverse engineering and description of the warnings on the dash. Finally, some technical details. I would assume this information would apply to other years in the same generation of truck, but outside of...

hdrams.com

RAM also continually sends a pulse to the trailer brakes to see if they are still operational. With the trailer connected, if you put your ear next to the trailer wheels you can hear a constant "ticking" noise. That's the pulse coming from the RAM truck IBC. Its said that pulse is checking the resistance of the trailer brake circuit. If the trailer brake resistance from the pulse changes out of range the truck throws the "Check Trailer Brake Wiring" or "Trailer Brakes Disconnected" messages.

Then there is the issue of trailer manufacturers using too small of wire gauge when wiring up the brake system, which kind of confuses the truck sensing the trailer brakes. It's said Dexter requires or advises the use of 8-10 gauge wire to the trailer brakes but manufacturers are using 12-14 gauge.
And settings on the IBC, Light Electric, Heavy Electric, Light Electric Over Hydraulic and Heavy Electric Over Hydraulic.

Good luck tracking down your problem.