TM-9-2350-311-20-2

HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5

TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR CAB, ARMAMENT, SIGHTING AND FIRE CONTROL, ELEVATING AND TRAVERSING SYSTEMS AND ASSOCIATED COMPONENTS

DECEMBER 1993
TM-9-2350-311-20-2

  TM-9-2350-311-20-2 - Page 254 of 828

TM 9–2350–311–20–2
4–4
4–2
BEARING\RACE RING ASSEMBLY
This task covers:
Inspection
INITIAL SETUP
Tools
Artillery and turret mechanic’s tool kit
(SC 5180–95–CL–A12)
Materials/Parts
Lockwire (item 32, Appx G)
Lockwire (item 33, Appx G)
NOTE
•
Bearing\race ring assembly components vary between vehicles.
•
Vehicles with five contact arm assemblies have bearing assemblies with these characteristics:
Number of bearing balls is 212.
212 bearing balls are separated by 106 race ring spacers.
•
Not all vehicles with three contact arm assemblies have same race ring assembly components.
Some vehicles have 212 bearing balls mounted on 106 race ring spacers. Other vehicles have 213
bearing balls mounted on 213 helical compression springs. When maintenance inspections call for
replacement of bearing balls, helical compression springs are replaced by race ring spacers.
•
Vehicles having three contact arm assemblies (which have not had helical compression springs
replaced by race ring spacers) have these characteristics:
Number of bearing balls is 213.
213 bearing balls are separated by 213 helical compression springs.
•
Unit maintenance has the responsibility for lubricating the bearing\race ring assembly (para 2–9).
Inspection
1
Cut lockwire (1) to remove. Discard lockwire.
2
Remove three cap screws (2) and ball turret cover (3).
3
Replace headless straight pin (4), if damaged.
4
Manually traverse cab and look through access hole (5).
5
When looking through access hole (5), inspect bearing balls (6) and race ring spacers (7) or helical com-
pression springs (not shown) for damage or wear. If bearing balls, race ring spacers or helical compression
springs need replacing, notify support maintenance.
6
If grease on bearing/race ring assembly contains dirt or sand, notify support maintenance. Race ring seal
(hidden) could be damaged.
7
After inspecting bearing balls (6), race ring spacers (7) or helical compression springs (not shown) for the
entire 6400 mil traverse, install ball turret cover (3), three cap screws (2) and new lockwire (1).


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