Meritor TM Series Service Manual page 17

3 Inspection & Maintenance
Drumbrake Axles
Refer to the appropriate Meritor hvs drumbarke service manual for
detailed disc brake inspection procedures.
Inspect Camshaft and Camshaft Bearings for Wear
Place a lever between the camshaft and axle beam close to the
cam head bearing and lever up and down to detect free
movement (Fig. 3.1). This should not exceed 3.0mm total
movement at the bush (the amount at the lever will depend on the
lever length so discretion and judgement is required).
Similarly place the lever between the axle and camshaft close to
the spherical bearing at the spline end of the camshaft and lever
up and down checking for similar play as at the cam head
bearing. If the play exceeds the above amount this suggests wear
has occurred and the camshaft and bearings should be replaced
as necessary.
Inspect Brake Drum
With the brake drum removed from the vehicle.
Clean excess brake dust from the brake drum and inspect the
drum braking surface for corrosion, excessive wear or other
damage.
CAUTION
: Never use an air line to blow dust from
the brake/drum area. If inhaled any form of dust can
at best be an irritant, at worst dangerous. Whenever possible
remove dry brake dust with a vacuum brush. Alternatively
wipe the areas with a damp cloth, never try to accelerate
drying time by using an air line.
Remove light corrosion by using coarse emery cloth at an angle of
45 degrees in one direction and then 45 degrees in the other
direction to produce a cross hatch effect. DO NOT USE ANY
FORM OF POWER TOOL.
If the drum braking surface shows signs of light heat crazing it
usually can be reused (Fig. 3.2) but if the heat crazing is severe
the drum should be replaced. (Fig. 3.3)
Should the drum life be extended by turn-out machining the
recommended machining limit should be 423 mm diameter so
that during the projected wear-out life of the shoes the final drum
diameter must not exceed 424.0 mm.
Similarly excessively worn drums should be inspected and on no
account should drums of diameter exceeding 423 mm be re-
assembled with new brake shoes.
Meritor HVS TM Series Axle
17
Fig. 3.1
Fig. 3.2
Fig. 3.3