[VAC] Re: Loosey Goosey Brake Magnet?

[Jim Dunmyer <jdunmyer@xxxxxxxxxxx>]

Greg,
 Your brakes look exactly as they're supposed to. The magnet is held in
loose contact with the "armature" on the drum. That's the flat surface
on the inside face of the drum. When the controller applies current, the
magnet drags much harder and is pulled in the direction of rotation,
moving the long lever arm with the cam on the top end. The cam expands
the brake shoes, causing a LOT of friction and the trailer to slow down.

While in there, I ususally disassemble the brake parts, clean off the
rust, look at the depth of lining over the top of the rivets to guess if
it can go another season, etc. I disassemble the adjusters and lube the
screw and the end pieces with wheel bearing grease, being careful to
wipe away any and all excess. I also usually lube the friction points on
the cam surfaces and the cam itself, again taking care to have no excess
grease left over.

Pay attention when reinstalling the adjuster, they often can be
installed either way. This is of no consequence, but you want to KNOW
which direction to turn the adjuster to tighten the shoes. I always try
to make mine so "Up" with the brake spoon (adjusting tool) tightens the
brakes. Make all of your wheels the same so you don't have to figure it
out.

You'll get a lot of scraping as you describe if the trailer has set for
a long time and the drums are very rusty. The "normal" sound when the
drums are clean and the brakes properly adjusted, is a slight scraping
noise that is usually present over only part of the wheel's rotation.
Drag should be very light, just barely perceptable.

I'm assuming that you're familiar with packing bearings; those who
aren't can find the procedure described on Tom Patterson's site. Don't
forget to wipe a bit of grease on the lip of the seal and the surface of
the spindle where the seal rides.

                                             <<Jim>>