Brake question

[rwbradley]

Just a little background, my current trailer is a 3 year old HTT. I bought it at 1 year old in near showroom condition. It was apparently seasonally parked so very little mileage from the previous owner. It is a dual axel with Dexter Ez Lube hubs with electric drum brakes.
I finally got around to doing the bearings and brake inspection etc... a little late I know. Everything was uneventful, the bearings and the brakes were in good condition.
The one thing that I find odd was the rear driver side brake. What I found odd was that the brake assembly looked to be in new condition, like right out of the box new, where as the rest had lots of brake dust and I could feel the drag when I turned the hubs. This one did not drag, so I assume the shoes were never ever making contact with the hub, but it only took about 4 notches until I could feel/hear it drag.
What I wonder is, is 4 notches out really enough that the shoes would never ever touch the hub even in an emergency stop or should I be checking the electrical to make sure it is working at all?

[rwbradley]

I appreciate all the comments, just to clarify a few points...
1) Absolutely no brake dust at all, no sign of wear on the shoes or drum, and generally pristine look of all springs, adjusters and all parts inside the drum. However I forgot to look closely at the magnet so not certain of its condition. The other 3 hubs had was I thought was "normal" wear and dust levels inside the hub.
2) I do not believe the issue is intermittent as a perfectly clean hub interior and no wear seems to suggest the pads have never made contact since it rolled off the assembly line.
3) I did both variations of the test, pulling the breakaway cord and then testing with a compass as well as jacking it up and trying to turn the hub. The magnet clearly was magnetized and I also could not turn the hub. This was after I adjusted by four notches, so I assume all is good now. I just cannot get past the idea that 4 notches was all it took to go from no contact to full power...

[Boon_Docker]

Nothing was said about no wear on the magnet or armature, just a mention about brake dust on the other brakes.

[RJsfishin]

Is it possible that brake assembly was replaced, and not used before you bought it ??

[Lynnmor]

Boon Docker wrote:


If the magnet is energizing then it is possible that it was assembled wrong, with a right side brake unit put on the left side by mistake.

He said it had no wear at all, which tells me that the magnet was not energized for most of the braking time. A weak or poorly connected magnet may be fine for spinning a compass, but do little for operating the brake shoes.

Even if the brakes were reversed, some signs of magnet wear should be apparent.

[Boon_Docker]

I have never heard of a "break away battery" on a travel trailer, utility trailer yes, but not a TT.

If the magnet is energizing then it is possible that it was assembled wrong, with a right side brake unit put on the left side by mistake.

[Kayteg1]

I would check the break-away battery first. If that is one of those 2x4" batteries, you don't have much capacity for brakes testing and repair in it.
You need bigger battery for that.
4 notches is plenty for shoes slag.

[Lynnmor]

rwbradley wrote:
Thanks for the advice... that was an easy test. Looks like the magnet is getting electrical. I am really surprised that the brakes being out so little would mean absolutely no contact to the drum...

That 4 notches was not the problem, there is something else going on. It may be intermittent.

[rwbradley]

Thanks for the advice... that was an easy test. Looks like the magnet is getting electrical. I am really surprised that the brakes being out so little would mean absolutely no contact to the drum...

[Lynnmor]

You have some good answers. My PA state inspected brand new trailer was like yours. It had a brake wire crimped with the insulation still covering the wire.

[Joe_Way]

The breakaway switch is powered by the house battery if it is correctly wired.

[rwbradley]

Both great ideas...
does the break away switch get power from the house battery as well or do I need to plug the 7 pin connector into the TV?

[mbopp]

Jack up that wheel, pull the break-away pin, and try to spin the wheel. It should move maybe 1/8-1/4 turn then lock up solid. If it doesn't lock up look for a broken wire to the magnet (favorite spot is where the wire goes into the axle.) Or you may have an open magnet.

[Old-Biscuit]

Check that magnet is actually getting voltage.

Hold a compass next to that wheel down low where magnet is located
Then have someone pull the Emergency Breakaway Switch Pin
If magnet is being energized the compass needle will deflect towards magnet

(Pulling Pin allows FULL Battery Voltage to be applied and Checks that Emergency Breakaway Switch works-----don't leave it out longer than necessary to test)

Bet that wire connectors for that brake assembly magnet are loose/corroded or wires are chafted and magnet has not been getting voltage