7251 MARINE GEAR Caterpillar


Lower Shaft

Usage:

Removal

1. Remove the upper shaft group. See the covering topic.

2. Remove the planetary reduction gear. See the covering topic.


PREPARING TO REMOVE LOWER SHAFT
1-Bolts (four). 2-Baffle. 3-Bolts (two). 4-Sun gear and shaft.

3. Remove bolts (1) and bolts (3) and remove baffle (2). There are nuts, spacers and a splash pan behind the baffle secured by bolts (3).


PREPARING TO REMOVE SUN GEAR
4-Sun gear and shaft. 5-Bolts (four). 6-Plate.

4. Remove bolts (5) and locks and plate (6).


REMOVING SUN GEAR

5. Using an 8H705 or a 1P2332 Puller Assembly and an 8B7561 Step Plate, pull the sun gear off the shaft.


PREPARING TO REMOVE SUN GEAR SHAFT
7-Bolts (two). 8-Retainer. 9-Lubrication line. 10-Bolts (two). 11-Bracket.

6. If the sun gear does not require being removed separately, the sun gear and shaft can be removed as a unit by disconnecting lubrication line (9), removing bolts (10) and bracket (11). Remove bolts (7) and pull the sun gear and shaft out from the rear.


PREPARING TO REMOVE ASTERN DRIVEN GEAR
12-Bolts (eight). 13-Astern driven gear.

7. Remove bolts (12) and insert forcing screws as shown.


REMOVING ASTERN DRIVEN GEAR

8. Loosen line (9), remove bolts (10) and lift off bracket (11). Remove bolts (14) and retainer (18). Remove bolts (7) and plate (8). Remove bolts (16) and retainer (15). Remove bolts (18) and retainer (19).


PREPARING TO REMOVE LOWER SHAFT
7-Bolts (two). 8-Plate. 9-Lubrication line. 10-Bolts (two). 11-Bracket. 14-Bolts (eight). 15-Retainer. 16-Bolts (six). 17-Bearing retainer.


PREPARING TO REMOVE LOWER SHAFT
18-Bolts (six). 19-Bearing retainer.


FT850 LOCKING BRACKET INSTALLED
20-Ahead driven gear

9. Install the FT850 Locking Bracket between the ahead driven gear (20) and the housing web. Tighten the locking bracket, adjusting bolts evenly between the gear and housing web. The adjusting bolts will "bottom out" against the web and provide a larger surface area on the web when the lower shaft is pulled out of the housing. This will prevent breaking the web when a force is exerted on the lower shaft and ahead driven gear.


REMOVING LOWER SHAFT

10. Using an 8B7548 Push Puller, 8B7550 Legs, 8B7557 Adapters, 7F1858 Screw, 5F7352 Thrust Bearing, 7F1859 Nut, 1P1842 Bearing Pulling Adapter and a 7F9540 Hydraulic Puller, start to pull the shaft from the housing.


NOTICE

Be sure the key holding the ahead driven gear to the shaft is free while removing the shaft to prevent damage to the housing.


11. After pulling the shaft to the bridge, change to 5F7369 Legs, install a sling through the ahead driven gear and continue pulling the shaft as shown.

12. Inspect the bearings and replace if worn or damaged.

Lower Shaft Installation

1. Install the lower shaft through the first web of the housing and through ahead driven gear (20). Push the shaft in as far as possible by hand. Make sure keyway and key on lower shaft and gear (20) are aligned.

2. Install retainer (15), locks and bolts (16).

3. Install bearing retainer (17) and using bolts (14), pull the lower shaft into place.

4. Install bearing retainer (19) and bolts (20).

5. Install the key in the lower shaft.

NOTE: Gears can be assembled on the shafts by heating them in oil to 275° F (135° C) Max., and quickly slipping them on the shafts.

6. Install gear (13) on the lower shaft.

7. Install gear retainer and bolts (12).

8. Remove bolts (8) and retainer (17).

9. Install the sun gear shaft and secure at the front end with retainer (8), locks and bolts (7).

10. Replace retainer (17) and bolts (14).

11. Install sun gear (4) and secure with plate (6), locks and bolts (5).

12. Install the brass lubrication tube and bracket (11), locks and bolts (10). Bracket (11) will not bottom against retainer (15) if the brass lubrication tube is installed incorrectly.

13. Connect lubrication line (9) at housing wall.

14. Install baffle (2), locks and bolts (1), nuts, spacers and splash pan behind baffle (2) secured with bolts (3).

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