If the outer nut is tightened on a
loose inner nut and the inner nut
becomes loose, the outer nut is dif-
ficult to remove.
HUB BREAKDOWN AND WHEEL BEARINGS.
General. The hub supports the dual wheels mounted to the hub
flange. Each hub is mounted on the axle spindle by means of two
tapered roller bearings equipped with grease seal, spindle nuts for
adjustment purposes, and hub caps.
Removal and Disassembly.
(1) Remove the wheels.
(2) Disconnect air lines from the towing vehicle and open drain-
cock on the trailer air reservoir tank to be sure brakes are
fully released with no contact between the brake shoes and the
(3) Remove the hub, brake drum, and bearings, as illustrated in
Cleaning, Inspection, Lubrication and Repair.
(1) Wash all parts in cleaning solvent and dry thoroughly, removing
all old grease from wheel bearings.
(2) Inspect hub and brake drum for cracks, scoring, overheating,
and out-of-round condition. Replace hub and brake drum if
out-of-round exceeds 0.010 inch.
(3) Inspect all parts for wear and defects. Inspect bearing cones
and rollers for pitting, chipping, and broken rollers.
(4) Replace worn and defective parts.
(5) Pack wheel bearings by kneading lubricant into all the openings
and completely filling all spaces in the cones.
Reassembly and Installation.
(1) Install the hub brake drum assembly in reverse order of b.
(2) Adjust wheel bearings as instructed in e.
(3) Close draincock on the air reservoir and connect the lines to
the towing vehicle.
(4) Install the wheels.