Electric Brake Overhaul???

It seems that my electric brakes on my tandem axel steel trailer are loosing their "grip". I test them by flicking the brake controller to MAX BLAST when pulling out of the driveway and easily notice the extra drag of the trailer but their effectiveness seems to be waning over the years. My boat/trailer combination is probably close to 10K lbs so I'd like to know the trailer brakes are working as designed - my truck is an F350. What is a good test to determine if electric trailer brakes are up to snuff?

maybe check the shoes?

Most of these have a manual adjustment which has to be done regularly. I’d try that first with the star wheel thru the backing plate…..

Anything that is easier ?

It is what it is, manual adjust drum brakes have to be adjusted regularly. Like my 1960s VWs and other old cars. Not hard, just spin the wheel, fwd, then tighten the star wheel till it locks, back off 10 or so clicks...spin it again, you should hear a bit of scraping of the shoe inside but no drag.
I put such few miles on my trailer I only have to do it once every 5 years or so. They do make self adjusting drum brakes but the are more complex. Only other option is electric over hydraulic disc brakes, a better system but also more complex. Electric + hydraulics.

I have electric brakes on my 33’ travel trailer that I maintain so I will try to help.

First off, the idea of moving your cab controller over to the max to see if the trailer weels lock up is a good idea and one that I do every single time I head out.
Second off, these are not your typical brakes and work on magnetism. In case you are not familiar, here is a great short vid that explains it (link).
Assuming the truck, controller and the connection to the trailer is 100% good there are 3 elements that need attention and maintenance.

1. The electrical wiring itself. There is a lot of current flowing thru it and any degradation of a connection (ex., corrosion) will lead to brakes not performing as they should. Careful attention to all the splices is warranted as well as the wiring runs themselves > they can be held in place by clips that over time chaff the wire and cause a short, etc.
2. The magnet / hub combination. Typically, the magnet will wear out before issues with the hub. But if the hub is heavily grooved / rusty the brakes will be less effective.
3. Brake shoes. These too wear out just like on a car based on milage. As they wear there is NOT an auto-adjust like on car drum brakes and thus must be maintained. Here is a good vid showing how to (link). Being able to adjust the brakes assumes all is good inside the drum area, i.e. its not all rusted.

Which leads to my strong suggestion since effective braking on a 10k boat/trailer combo is critical to both you and others around you on the road:

• Pull each drum assembly off the trailer and do a very thorough inspection, looking the points above and more. I even go so far as to use a DC induction meter and measure the currents to each of the mags to ensure its balanced.

Good luck and ask questions as needed.

Edit: thanks for posting your query as I did not know there are boat trailers out there with electric brakes (not the electrical over hyd, I get those, but pure electric like in the video). This is a surprise to me as the combination of electricity and water in this manner do not compute in my mind. But always willing to learn, I now know.

That's why I like surge brakes, yes they are not controllable like electrics but as long as your master cyl works, your brake cyls or caliper pistons aren't seized, and there are no leaks (obvious) your brakes work. Electric is more points of possible failure.

Lou C said:

That's why I like surge brakes.... Electric is more points of possible failure.

Click to expand...

I completely agree!

Quick follow up on more fully answering your question regarding “overhauling” these brakes:

They make kits that complexly replace the backing plate and are fully loaded with new shoes and a mag. See this link as an example. This really is the easiest and most cost-effective way to overall these sorts of brakes, especially after all the years of immersion in water. A kit like in the link assumes the drums are ok but you can get kits with new drums as well. Get the drums turned as part of the overhaul if keeping the old ones.

Important note: splicing in the new mag is the most delicate operation and needs to be properly sealed. Connectors like these Crimp- Solder – Seal similar to these (link) are the way to go. And over that I would uses ‘double wall shirk tube’ (link) to really seal it up against water intrusion. Double wall refers to a glue on the inside. Remember to put the shrink tube on the wire before you make the connection.

Good luck!

I know they are not common but I did see a set of galvanized backing plates for electric brakes, also if you look for them you can get zinc coated brake drums. These would last much longer than plain painted brake assemblies. Here's some tips from maintaining drum brakes in salt water....
1) with a new backing plate, extend the adjuster star wheel by clicking it so it exposes most of the threads, then coat those threads with a thick water proof grease like OMC/Evinrude triple guard grease. Most often the headache with adjustable drum brakes is that the adjuster seizes due to corrosion.
2) pick up a drum brake adjusting gauge, this will allow you to set the shoe adjustment to the actual diameter of the drum, which makes it easier to get the adjustment correct
3) this doesn't apply to electric brakes but it does to hydraulic brakes, you can remove the wheel cylinder, then pack the area under the dust boot with synthetic brake caliper grease. This will keep water out of the brake piston area and give them a longer life before they start to seize up.

The ones on my trailer now have these hard to find bootless wheel cylinders, they seem to last the longest because they don't hold water. These have been on about 4 seasons and are working well. The more common style of wheel cylinder with the boot, will work properly longer if you use the grease to keep the water out. When I upgraded the trailer from a 2x2 3500 lb axle to a 6000 lb 2x3 drop axle I also upgraded the brakes from 10" drums to 12" drums. The 12" brakes are rated to stop 6,000 lbs.

12" brake with bootless wheel cylinder (uses an O ring inside)

zinc coated 12" brake drum

size comparison 10" brake vs 12" brake

Very likely the shoes were never burnished properly.

Do this procedure before you do anything else:

"Edit: thanks for posting your query as I did not know there are boat trailers out there with electric brakes (not the electrical over hyd, I get those, but pure electric like in the video). This is a surprise to me as the combination of electricity and water in this manner do not compute in my mind. But always willing to learn, I now know. "

I switched to electric brakes 3 years ago on my '04 Karavan tandem pontoon trailer after spending countless hours and hundreds of dollars trying to get my surge brakes to work properly since 2017. 10" wheels, 7" brakes.
And the last 2 years have been in brackish with a mid season dunk in fresh lake water. So it's launch in spring, dunk in summer, retrieve in the fall. Not much exposure. I'm using a rust/corrosion preventative spray inside the drum (no, not the shoes). So far no issues.