1995/10/23 Caterpillar

772 (80S),
772B (64W),
776B (6JC),
776C (2TK) Tractors;
773 (63G),
773B (63W),
777B (4YC, 3NF),
777C (4XJ) Trucks;
775B (7XJ) Quarry Trucks

SUPPLEMENT: 01/08/96

Service Magazine; October 23, 1995; Page 14; "Improved Wheel Bearing Cone Anti-Rotation System Prevents Wheel Bearing Cones From Rotating On The Axle Housing" for 772, 772B, 776B, 776C Tractors; 773, 773B, 777B, 777C Trucks; 775B Quarry Trucks. Disregard this article. See the article with the same title in this issue.

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Description of Change:

Reference: Service Magazine; July 8, 1991; Page 3; "Procedure To Prevent Rear Wheel Bearing Cones From Rotating On Axle Housing" for 776B Tractors; 777B, 785, 789 Trucks.

Service Magazine; January 10, 1994; Page 6; "New Rear Wheel Bearing Adjustment Procedure" for 776, 776B, 776C Tractors; 777, 777B, 777C Trucks.

Reference: Guideline For Reusable Parts, SEBF8083-02, Procedure To Repair Worn Wheel Spindle And Hub for Off Highway Trucks.

NOTE: The new rear wheel bearing adjustment procedure for the 776C Tractors and 777C Trucks, in the January 10, 1994 Reference article, can be applied to 772, 772B Tractors, 773, 773B Trucks and 775B Quarry Trucks with the following changes.

* Step 1. Install four equally spaced bolts instead of six.

* Steps 5 and 7. Tighten the four bolts to 70 ± 5 N·m (50 ± 3 lb ft).

* Step 13. Add 0.23 + 0.00 - 0.05 mm (.009 + .000 - .002 in).

* Step 14. Use ten 0S-1625 Bolts instead of twelve.

The rear wheel bearing cones may rotate on the axle housing.

Adaptable To: The new parts used in this change are shown in Charts 1, 2 and 3. The new parts are listed as "Phase II Part No.". and the former parts are listed as "Former Part No.". This change is effective with 772B (64W194), 776C (2TK79) Tractors, 773B (63W4010), 777C (4XJ343) Trucks and 775B (7XJ122) Quarry Trucks. Earlier machines can be reworked by using a 106-9612 Dowel, 16.05 mm (.632 in) diameter by 25.4 mm (1.00 in) long, and following the procedure below.

NOTE: Some of the former axle housings for the 772B Tractors, 773B Trucks and 775B Quarry Trucks had holes for the ball retainers even though the balls were not used.

NOTE: An undersize bearing cone is available for the axle housing outer wheel bearing station on the 776B, 776C Tractors and 777B and 777C Off-Highway Trucks covered in this service magazine article. The undersize cone provides an alternate means (other than spray metalization) of reconditioning an axle housing that is damaged at the outer bearing station. The undersize bearing cone part numbers are included in Chart 2.

NOTE: If all new parts are installed, the recommended 2000 and 6000 hour wheel bearing adjustment intervals can be eliminated.

The outer bearing journal axle housing diameter, and the "over the axle housing" dowel projection dimension for the undersize bearing journals are shown in Chart 4.

Illustration 1. New parts location.

Procedure To Rework The Axle Housings To Accept 106-9612 Dowel.

NOTE: Reworking axle housings to utilize a ball to keep the bearing cones from rotating is NOlonger recommended.

NOTE: When installing the cone anti-rotation system, the axle housing bearing journal maximum wear limit is 0.102 mm (.0040 in) diameter. SEBF8083-02, see "Reference", allows an axle housing diameter wear limit for re-use of 0.20 mm (.008 in). This is NOTacceptable with the cone anti-rotation system.

NOTE: Dimension "J" for the machines in this article is 5.0 mm (.20 in) less than was previously recommended. This dimension moves the inner axle housing slot 5.0 mm (.20 in) toward the machine center line and matches current production dimensions. This dimension requires the use of new part number seal retainers and 106-9612 Dowel.

Illustration 2. Slot end view. Section through slot in axle housing bearing race. Inner and outer slot end view dimensions are the same.

Illustration 3. Axle housing outer race.

Illustration 4. Axle housing inner race.

Illustration 5. Outer bearing cone slot profile.

Illustration 6. Inner bearing cone slot profile.

NOTE: Dimension "F" is the dimension from the end of the axle housing to the outer dowel slot. Dimension "G" is the outer diameter of the axle housing. Dimension "H" is the dimension over a properly installed outer dowel. Dimension "J" is from the axle housing seal retainer flange to the inner dowel slot. Dimension "K" is the length of the inner dowel slot. Dimension "L" is the dimension over a properly installed inner dowel. Dimension "M" is the inner diameter of the axle housing.

Machine slots in the axle housing using the dimensions shown in Chart 4 and Illustration 1. The slot should be placed on the same centerline as the threaded hole for the AETA pickup. The cone slot must be machined with a blunt end mill cutter or equivalent to be compatible with the dowel/cone anti-rotation system.

NOTE: To avoid heat distortion of cone race, use slow feeds and speeds.

Use Illustrations 5 and 6 to identify the correct bearing cone slot profile. If the profile of the slot is not correct, it can be modified according to the dimensions in Illustrations 5 and 6. Dimension "M" must be maintained.

Procedure to Rework The Axle Housing To Accept Undersize Bearings.

Illustration 7. Outer axle outer race dimensions for undersize bearings.

NOTE: Dimension "Q" is over the axle housing dowel projection dimension of a properly installed outer dowel on an undersize outer bearing journal. Dimension "R" is the undersize bearing cone outer bearing journal diameter.

Illustration 7 shows the dimensions for an undersize axle housing. Also see Illustrations 1,4 and 5.