Tag Axle Brakes

[cooperhawk]

What is the proper method for adjusting the tag axle brakes on a 1984 345 motorhome?
I manually actuated the brake controller while coasting and felt no braking. I then jacked up one wheel fully depressed the brake controller and spun the wheel. There was no drag by the brakes. I then measured the voltage at the resistor and found that a little over 6 volts was going to the magnets. I then jumpered the resistor to put a full 12 + volts to the magnet and the brakes worked properly (couldn't turn the wheel). Now how do I adjust the resistor to get the proper voltage to the magnets to make sure that the tag axle brakes do not come on prior to the primary rear brakes? Is there a procedure for doing this?

[Inland RV Center, In]

Gunner.

Your motorhome sholud have a "slider" type resistor block.

Take the slider apart.

Clean the bottom and top half of the slider with a wire brush.

Reposition the slider in it's original location, or there abouts.

That will fix your "low voltage." at the brakes.

The problem is the sliders are a "shunt." When the shunt becomes corroded, however slightly, it no longer makes connection. Therefore the entire resistor comes into the circuit, reducing the voltage excessively.

Andy