9-5. REAR HUB AND DRUM MAINTENANCE (Contd)
b. Cleaning and Inspection
Drycleaning solvent is flammable and will not be used near open
flame. Use only in well-ventilated places. Failure to do so may
result in injury to personnel.
Do not use compressed air to dry bearings. Damage to bearings
Clean all hub and drum components with drycleaning solvent and allow to air dry.
Inspect drum (8) for deep grooves, cracks, scores, and elongated holes. Replace drum (8) if cracked or
holes are elongated. Notify your supervisor if drum (8) is grooved or scored.
Inspect adapter (9), deflector (10), and spacer (4) (if so equipped) for cracks, warpage, or elongated
holes. Replace adapter (9), deflector (10), or spacer (4) if cracked, warped, or holes are elongated.
Inspect bolts (11) and studs (15) for breaks, bends, and damaged threads. Replace bolts (11) or
studs (15) if broken, bent, or threads are damaged.
Inspect hub (2) for cracks, breaks, and scores. Replace hub (2) if cracked, broken, or scored.
Bearings and bearing cups must be replaced as a matched set.
Perform steps 7 through 9 if hearings and bearing cups are to be
Inspect bearings (16) and (24) and bearing cups (1) and (3) for damage. Replace bearing(s) (16)
and (24) and bearing cup(s) (1) and (3) if damaged.
Using soft hammer and brass drift, remove bearing cups (1) and (3) from hub (2). Discard bearing
cups (1) and (3).
Inspect bore of hub (2) for scores, grooves, and wear. Replace hub (2) if bore is scored, grooved,
Using arbor press, install new bearing cups (1) and (3) in hub (2). Ensure bearing cups (1) and (3)
are seated properly.
1. Pack inner and outer bearings (16) and (24) with GAA grease (LO 9-2320-260-12).
2. Apply light coat of GAA grease to rubber section of new inner bearing seal (17) and inner and outer
bearing cups (3) and (1).
1. Install ten wheel studs (15) in hub (2).
Perform step 2 on M821 models.
Assistant will help with step 3.
2. Install ten wheel studs (15) and spacer (4) on hub (2).
3. Aline and install drum (8) and adapter (9) on hub (2) with ten new lockwashers (14) and
screws (13). Tighten screws (13) 81-104 lb-ft (110-141 Nm).
4. Install safety wire (12) through screws (13).
5. Install deflector (10) on adapter (9) and drum (8) with ten bolts (11).