trailer brake problem

Discussion in 'Mechanic and Repair' started by JTS Landscaping lawn, Jul 22, 2006.

  1. JTS Landscaping lawn

    JTS Landscaping lawn LawnSite Senior Member
    Messages: 378

    i have a gooseneck trailer with electric brakes on one axle. the problem im having is that doesnt seem like there is enough power or something going to the brakes. i have the controller turned up all the way and its barely stopping me in not at all then i manully do it as im pushing the brakes and there is a little more power to them but still not enough. wondering what some of you guys think might be wrong. thanks
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    I believe I would check the adjustment on the brake shoes, Every so often we have to adjust ours.
  3. PLM-1

    PLM-1 LawnSite Bronze Member
    Messages: 1,640

    I was thinking that also. You may also check your controller. Sometimes if you have the all digital one, not with the pendulum, they go bad.
  4. Team-Green L&L

    Team-Green L&L LawnSite Bronze Member
    Messages: 1,775

    I agree with checking the shoes. Also brakes on one axle for a gooseneck trailer seems a little odd. Usualy a trailer that heavy has breaks on both axles.
    Does your brake controller have an adjustment for the delay? If so you may want to check it, the delay may be turned up causing the brakes not to kick on in time, that may be why when you apply them manually you feel it more right away.
  5. mcambrose

    mcambrose LawnSite Senior Member
    Messages: 518

    There is also a magnet in the brakes that can go bad over time. They aren't very expensive and fairly simple to replace.
  6. PLM-1

    PLM-1 LawnSite Bronze Member
    Messages: 1,640

    The magents are actually sorta expensive, at least in this area. I can buy a new backing plate ready to bolt on and connect wiring for $90/ axle. I find that the cheapest, easiest and cleanest way to fix the brakes. If you just replace the shoes and magnets, chances are you still would have a bad return springs. So, like I said, just replace the entire backplate.
  7. Jim@MilkyWay

    Jim@MilkyWay LawnSite Senior Member
    Messages: 472

    Rob is right. Assuming you have checked the linings, and if adjustment OK, then try this. You will need a Digital (or other) Multi Meter, a large flat washer, and maybe some pliers or wire stripper.
    Remove wheel, access and remove wire nut or what ever type splice, where magnet leads connect to harness and do whatever is necessary to connect DMM to magnet leads as close to magnet as practical; not at front end of trailer.
    Set meter to read DC volts, 20 volt range or whatever. Hold meter leads on magnet leads while a friend applies brake. If you do not get 12Vdc across the magnet, then you have a open circuit; could be a bad ground, could be a bad connector.
    If you _do_ get 12Vdc across leads, then put the washer to the magnet and make sure the magnet attracts when brake applied. If voltage present but magnet does not energize, then replace plate, as it would seem the electro-magnet is open (wire broken inside)
    Repeat on other wheel.
  8. olyman

    olyman LawnSite Gold Member
    Messages: 3,649

    jim@milky has good point--on addition--you may have 12v at the multimeter--but no amps--in other words--you may have a connection ready to break--only a couple of the strands of wire are carrying the load--takes ALL the wires to carry the AMPS--i/e the voltage to the brake shoes takes both volt, and amps---
  9. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,592

    I usually use a rubber band to hold the manual lever on the controller in the actuated position. This keeps power on without need for a helper. I have also noticed that the magnet will buzz if that always the case? I don't understand your comment to "replace Plate" if voltage is present? I assume that means replace the magnet?
  10. Jim@MilkyWay

    Jim@MilkyWay LawnSite Senior Member
    Messages: 472

    They do make some funny noises don't they? But, have you ever noticed that the exact same brake can/will make entirely different sounds the very next time you test it; that is, like from one minute to the next? That is the problem. The sounds made can range from none at all to buzzing,humming,whistling and combinations of any.
    The reason I suggested accessing the conductors (wires) of the magnet as close to magnet as practical is because, if you are literally checking voltage at the wires, where they disappear into the magnet and you_do_ have good voltage there (close to 12Vdc) then you have eliminated power supply as the problem. In other words, if the magnet is getting power and still will not energize, then the coil which is the elctro-magnet is open/bad. It was stated that replacing the entire assembly is both desirable and not much, if any more costly than replacing just the magnet. This I personally can neither support nor argue.
    That really _only_ (boy, now THERE is a statement looking to start an argument) applies to batteries not under load. However, the resistance of coils etc can be tested and used in conjunction with the voltage test to get the full pic.
    In other words, if you do in fact have voltage across a component, and all is in good repair with that component, and that is a big if, then the current will flow as predicted.

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