Helio O Series Owner's Manual page 36

Brake cleaning and inspection
Your Helio travel trailer brakes must be inspected and serviced
every 6 months intervals or more often as use and performance
requires. Magnets and shoes must be changed when they become
worn or scored thereby preventing adequate vehicle braking.
Brake drum inspection
There are two areas of the brake drum that are subject to wear
and require periodic inspection. These two areas are the drum
surface where the brake shoes make contact during stopping and
the armature surface where the magnet contacts (only in electric
brakes.) The drum surface should be inspected for excessive wear
or heavy scoring. If worn more than .020" oversized, or the drum
has worn out of round by more than .015", then the drum surface
should be turned. If scoring or other wear is greater than. 090"
on the diameter, the drum must be replaced. When turning the
drum surface, the maximum rebore diameter for a 7" brake drum
is 7,09".
The machined inner surface of the brake drum that contacts the
brake magnet is called the armature surface. If the armature
surface is scored or worn unevenly, it should be refaced to a
120 micro-inch finish by removing not more than .030" of
material. To insure proper contact between the armature face
and the magnet face, the magnets should be replaced whenever
the armature surface is refaced and the armature surface should
be refaced whenever the magnets are replaced.
It's important to protect the wheel bearing bores from metallic
chips and contamination which result from drum turning or
armature refacing operations. Make certain that the wheel bearing
cavities are clean and free of contamination before reinstalling
bearing and seals. The presence of these contaminants will cause
premature wheel bearing failure.
Magnets
Your electric brakes are equipped with high quality electro-
magnets that are designed to provide the proper input force and
friction characteristics. Your magnets should be inspected and
replaced if worn unevenly or abnormally. As indicated below a
straightedge should be used to check wear.
Brake size Ampere / magnet
7" x 1 1/4" 2.5
Storage preparation
If your trailer must be stored for a period of 90 days or more, it's
important to adequately prepare it in advance:
1. Lubricate moveable mechanical parts, such as the hitch and the
parts of the suspension that are exposed to the elements;
2. Given the possibility that the upper part of the ball bearings
isn't covered in oil, it's more subject to corrosion. It's strongly
recommended to turn the wheels periodically (every 2 weeks)
when in storage for a prolonged period of time;
3. If possible, lift the trailer and place supports under the frame
to ease the weight off the tires. Never place the jack or the
supports under the axle tube or the stabilizers.
Two brakes Magnet Ohms
5.0 3.9
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