Forum Discussion

aarond76's avatar
aarond76
Explorer
Apr 09, 2013

Testing Trailer Brakes with Break Away Cable

Trailer has weak brakes even with controller set to full power.

Two trips back to dealer and dealer states brakes work fine and problem is with my vehicle (wiring). I do not believe them. The controller stopped my other trailer just fine set at much less than full power and would easily lock the wheels.

Can I pull the breakaway cable on the trailer to test the brakes. After pulling the cable in a parking lot and pulling forward it should lock the brakes up correct? If it locks the brakes with the breakaway cable pulled then the problem is on the van side. If it does not lock the brakes up then the problem is on the camper side.

How do I reset the breakaway cable after pulling it out? How long can the breakaway cable be pulled out before you start to cause problems fully energizing the brakes for a long period of time? Obviously I am not planning on driving down the road with the break away cable pulled.

Thanks.
  • brulaz's avatar
    brulaz
    Explorer
    Apr 10, 2013
    Ron Gratz wrote:
    Some trailer brakes will not lock -- even under full battery voltage.
    ...


    I've never been able to get mine to lock up on pavement. Maybe once on gravel. That's with either the P2 or Ford's built-in controller.

    But they do drag the truck to a halt pretty fast when set that high.
  • Ron_Gratz's avatar
    Ron_Gratz
    Explorer
    Apr 10, 2013
    Some trailer brakes will not lock -- even under full battery voltage.

    According to Dexter Axle:

    On an unloaded trailer, you may be able to lock up your brakes
    if your electric brake controller is supplying full amperage to the brakes.
    When loaded to capacity, you may not be able to lock your brakes
    as electric brakes are designed to slow the trailer at a controlled rate,
    and not designed to lock up the wheels on a fully loaded trailer.



    Ron
  • brulaz's avatar
    brulaz
    Explorer
    Apr 10, 2013
    I routinely check that my brakes are getting current by pulling the breakaway pin and measuring the current (clamp-on ammeter). You just plug the pin back in then.

    Not a problem. You should be able to pull the pin and try dragging the trailer. Or jacking it up and rotating the wheels.

    Any possibility that your bearing seals are leaking? That will reduce braking action a lot. I routinely check my brake drum temperatures by touch after a quick stop from highway speeds (like at a reststop). Once I noticed one of the drums was much less hot than the other. And sure enough, there was grease all over inside the drum.

    And yes, brake adjustment needs to be done every year, unless your brakes are self-adjusting (an easy and worthwhile upgrade).
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Apr 09, 2013
    Yes you can pull the pin which will allow full trailer battery voltage to be applied to trailer brakes.

    CAUTION:
    Disconnect your truck to trailer pigtail cord before pulling pin.
    Some brake controllers do not play well with the backfeed from full trailer battery power and can be damaged.

    After testing.....just push the pin back in.

    One thing.......have you/dealer actually checked the adjustment on the brakes.
    Jack up one wheel at a time, spin the wheel.....should be slight drag from brake shoes.
    IF not......brakes will not work correctly.

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