Quote:
Originally Posted by kguess
If my truck is connected to my Keystone, and while I have a wheel off, should the magnet grab something metal without applying the break? I'm trying to see if my magnets are working. Or does it only apply when the brake pedal is applied?
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The magnets are energized when the brake pedal is applied, sending a signal to the brake controller which, in turn, sends a measured amount of dc voltage to the brakes. The magnets are then attracted to the drum. Because the magnets are on an articulated arm, the movement of the magnet and arm is translated to outward movement of the brake shoes which grab the round inner surface of the drum, slowing the vehicle.
So, the magnet should not grab anything without being energized. You can use a multimeter to test for a complete circuit and measure the resistance through each magnet. You can also use the meter to verify that each brake assembly is receiving voltage when the brakes are applied.
You can also verify that each wheel's brake is working properly by raising that wheel off the ground by just a half inch or so. Spin the wheel and have someone apply the brakes. If the magnet (and the rest of the brake) is working properly, it should grab and stop spinning. Since raising the wheel and spinning it to adjust the brake shoes is a required step in maintenance, it's also the right time to verify brake function.
These drum brakes are simple systems, and have been in use in motor vehicles of all types for many, many years, well back into the first half of the 20th century. The only variation from standard car and truck drum brakes is the electrical activation via the energized magnet. And that has been a standard for almost as long. If you were to take apart a TT brake drum from the 1960's, you would find that it is virtually identical to the drum brakes on the newest TT's and fivers. And these systems are in use on many different utility trailers, too. In fact, the axle/suspension/brake/hub assemblies are same throughout the light trailer world. That's one of the reasons that you can find seals and bearings for your Keystone at most auto parts stores and utility trailer shops. Believe me, it's a lot easier and cheaper to find a Dexter part number 1234456 bearing than it is to find the same bearing by looking for one for your 2013 Keystone Cougar 326MKS.
The only variations are the newer RV trailer disc brakes, and the occasional hydraulic system actuating drum brakes.