Monday, November 7, 2016

Electric Brakes for your Boat Trailer

The first argument I hear against electric trailer brakes is, "Electricity and water don't mix!"

Totally electric brakes work by magnetism. Twelve volt power is used to make magnets. Sealed magnets. The strength of the magnets is determined by how much braking is called for. Magnets work in air, water or even a vacuum. There is absolutely no mixing of water and electricity.

The next argument I hear is that electric drum brakes don't hold up well with salt water dunkings.

I had a tandem boat trailer that had electric brakes on one axle and surge discs on the other because I got tired of replacing disc brake parts and decided to try all electric. The physical appearance of the drum vs the disc of course favored the disc - the drum did look rusty, but the function is what's really important. The electric brakes were far more reliable than the discs.

Here's how my boat trailer ended up with one axle being surge disc and the other being electric drum:
One of my boats came on a trailer without brakes. I told the shop I wouldn't take the (#3,600 gross) boat off the lot without trailer brakes, so at my expense, they put surge disc brakes on the trailer. Within 500 miles I had a bearing failure. The hub was replaced under warranty, but continued to run hotter than I liked, so I had a second axle put on the trailer. Actually, they put two new axles, with 4 new tires and a new actuator on while I waited. I was a happy camper.

After about another 500 miles I lost another bearing only 50 miles after I had checked the temps of the hubs with an IR gun. I was ready this time with a spare hub and was on the road again in about an hour. This is the reason disc brake folks carry so many spare parts and tools.

I experimented with ways to keep this from happening again, like a stiff spring to keep the brakes from coming on so soon, and leaving a tiny bit more clearance in the castle nut/bearing (an additional flat) to wobble the rotor so it would push the pads back into the caliper. I had good results with the heat problem, but only 3,000 miles after a complete disc brake overhaul (new pads, turned rotors) on the way to Alaska, there were no pads left on one brake, with the backing plate constantly gouging the rotor. We searched for parts and found electric brake parts available at auto parts and RV stores but no parts were available for my discs, so I had to lock out the brakes for the remaining 11,000 miles.


The van is a one ton, so not having trailer brakes wasn't all that scary. By the way, those are passenger car radials on the boat trailer.

When I returned home, I contacted the disc brake people. They said 3,000 miles was about all I could expect from the pads and I should just get some new ones (at about $35 each wheel). Trouble was the caliper pistons were corroded in the calipers too so I opted to put a set of electric brakes on that axle and continue to run the surge brakes on the other axle. The entire replacement from hydraulic disc to electric drum was $150 for both wheels, and installation was 4 bolts, 2 wires and a castle nut for each wheel.

Not long after the I put on the electric brakes, a hydraulic line ruptured on the disc brake side. I knew to try the bleeder screws on the calipers before I invested in any new parts - they broke off. So the second axle got electric brakes as well. Never had a problem after that - 80% of the time in salt water.The electric brakes were still working fine when I sold the boat.

"Sharkskin" on left, generic on right. The Sharkskin look better - the generic worked better.


What else about electric brakes?
*They work in reverse (you don't need a reverse lockout solonoid) - nice on a slippery ramp
*You can test them and apply them at will so you know they'll be there for you
*The square you see below, with the silver button is attached to the magnet arm and rotates when the magnet is energized, pushing the shoes outward. This is about as simple as it gets - no close tolerance hydraulics.


*No bleeding or bleeder screws to break off.
*No adjusting required with Nev-R Adjust brand
*There are no moving parts in the coupler with electric brakes
*New EVERYTHING is only about $150 per axle,
*Rebuild is 4 bolts and 2 wires at each wheel - includes drum, backing plate w/ shoes, bearings and seal.
*They are off while compression braking on steep down grades

But you will need a controller in your vehicle (the brakes will not work without one) and a breakaway battery on the trailer.

I'd been happy with the electric brakes on my boat trailer for years, then towed a different trailer with a new set of electric brakes on it and decided I'd replace the 40 year old drums. 


Go electric!

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