Near-north Ontario, French River | First off, when you push in the red button on the dash, can you see the slack adjusters backing off on the trailer? If they don't release you may have a bad trailer protection valve on the truck. Unplug the red glad hand from the trailer, with the red button on the dash in, do you have air coming out the red line?( you should have) If you have air getting the the trailer, are all the valves on the air tanks CLOSED? . If they are closed, try shutting the truck off and pushing in the red dash button, if you have a blow maxi-can ( the parking brake side of the trailer brake system) you should hear air blowing out, a badly blown maxi will be difficult to hear if the truck is running. Ok now you have those possibilities eliminated, when your trucks air system ( again with red button IN ) reaches 90psi or so, the trailer brakes should release. Do you see the slack adjusters moving at the brake chambers? If they don't move you have a plugged/defective valve at the trailer, either on the service side( the side that operates when you hit brake pedal ) of the air circuit or on the spring side (the emergency side ) Another possibility if the slacks don't retract is a faulty foot valve, or the trailer spike ( the lever on the right side of the steering column) is engaged. . If you see the slack adjusters retract, but the brakes don't release then its more likely a case of the shoes being stuck to the drums. Give the drums a whack with a small hammer and they should just pop loose. Lots of possibilities but should be very simple to figure out, just work you way down the line eliminating possibilities. |
Air brakes on trailer won't release, need help.
