Trailer Brake question

[cbgaloot]

I recently bought a used utility trailer with (maybe) electric brakes.

I haven't pulled a hub to see for sure yet. But there is a disconnected breakaway switch on the tongue. So I'm assuming there are some brakes under there.

My question is.

To activate the brakes is electricity applied to the brakes?

Or does electricity keep the brakes pulled away from the hub and removing the electricity lets the shoes contact the hubs?

Seems it would have to be the latter, or the breakaway switch would be of no purpose.

That said my hubs spin freely connected to my truck or not. And I know they are not working because my brake controller tells me so.

Thanks in advance.

[dereku]

the brakes are applied with electricity. The brake away box has its own battery.

[cbgaloot]

Originally Posted by dereku

the brakes are applied with electricity. The brake away box has its own battery.

AH! Now things make sense. I haven't found a battery so I am betting it was removed by a previous owner.


Thanks.

I got to crawl under there and get the brakes working. My F350 dually stops it just fine brakes or no, but it needs to be right in case it ever breaks loose.

I can just imagine my 16 foot box trailer bouncing across the freeway into the front of a Smart Car. Not pretty.

I found wiring diagrams all over the net but no explanation of how it all works.

[SuperCrutyPS]

If you look on the brake back plate, you should see wires coming out of them. That would mean you have brakes. As dereku stated, the break away circuit would use the trailer battery to apply the brakes in case the trailer and tow vehicle separates.

The way the circuit works is that voltage is applied to the brakes. There is a electro-magnet inside the drum. When voltage is applied, the magnet attaches it self to the brake drum face - that activates a cam, which in turn presses the brake shoes out against the drum. Works very similar to car drum brakes except it's electric. If the break-away is pulled, the battery on the trailer applies max voltage to the brake magnet to get max braking.

Here's a link:

http://www.amazon.com/10-Electric-Trailer-Brake-Assemblies/dp/tech-data/B001KN7A2W

http://www.amazon.com/10-Electric-Trailer-Brake-Assemblies/dp/tech-data/B001KN7A2W

I added that just so you'd have an idea of what the inside of the brakes might look like. Reference only.