2014/09/11 Caterpillar

Wheel Tractor-Scraper:

621H (S/N: DBK1-UP; HKK1-UP; NYY1-UP; EAZ1-UP)

623H (S/N: EDJ1-UP; DBF1-UP)

627H (S/N: LCT1-UP; DBW1-UP)

A new steering line assembly is now available on the machines listed above. The new steering line will not have any hoses attached to weldments on it when using certain starting arrangements, increasing its service life.

The new steering line assembly is not a direct replacement. Additional parts are required to perform this update. Refer to the Rework Procedure and Required Parts List below.

Illustration 1	g03694435

New 455-0971 Line Assembly (1) replaces the former 383-3529 Line Assembly and 362-3549 Line Assembly in the 310-5528 Steering Lines Gp .

Note: Use new hardware that is listed in Table 2 of rework procedure to install the new 455-0971 Line Assembly. The improved steering lines group will have the location change for the hydraulic oil sample port.

New 455-0998 Hose As (2) replaces the former 382-9826 Hose As in the 382-2780 Hydraulic Oil Lines Gp. This improvement is applicable only on machines using 384-9430 Cold Weather Starting Ar and 382-2789 Cold Weather Starting Ar .

The new 455-0971 Line Assembly and 455-0998 Hose As are adaptable to machines that are listed in Table 1.

Use the following rework procedure in order to update the steering lines group and hydraulic oil lines group on the machines listed above:

Rework Procedure

1. Put a vacuum on the tractor hydraulic tank to minimize oil loss and disconnect all hydraulic lines.

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Illustration 2	g03694442
View A

2. Remove the secondary steering flow switch (A), if equipped, from the former line assembly (B). Save the part.

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Illustration 3	g03694453
(D) Steering pump

3. Remove former line assembly (B) and 382-9826 Hose As (C) .

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Illustration 4	g03694445

4. Install new hose assembly (2) using two O-Ring seals (3), elbow (6), O-ring seal (7), spacer (8), and O-Ring seal (9). Refer to Illustration 4.

   Note: If the machine is equipped with standard start arrangement, use 9S-4185 O-Ring Plug and 3K-0360 O-Ring Seal on the 9W-1686 Spacer (8). The Standard Start machines do not need the 455-0971 Line Assembly (1), 6V-9877 Elbow (6), and 6V-9746 O-Ring Seal (3) .

5. Install new line assembly (1) to steering pump (D) using rectangular seal (11), four bolts (12), and four hard washers (13). Attach the other end of the line assembly (1) using O-Ring seal (10). Refer to Illustration 4.

6. Install the oil sample port to elbow (4) with O-ring seal (5) .

7. Install secondary steering flow switch (A) that was saved in Step 2 to the new line assembly (1) with a new O-Ring seal (7) .

   Note: Secondary steering flow switch (A) must be installed with the flow arrow on the side of the switch pointed in the direction of oil flow as shown in Illustration 4. The oil flow is away from the steering pump and toward the front of the machine.

   Note: If the machine is not equipped with the flow switch, plug the port with the plug from the former line assembly.

8. After the secondary steering flow switch (A) is orientated correctly, tighten the adjustable nut on secondary steering flow switch (A) to 58 ± 3 N·m (43 ± 2 lb ft).

9. Secure the harnesses below the line assembly (1) using existing bracket and ladder clip. Use cable strap (14) to attach the lower ladder clip to the power train harness.

10. Check oil level and purge the steering system. Refer to Testing and Adjusting, KENR8874, "Steering System–Purge".

11. After purging the system and topping the oil level, check the hydraulic lines for any leaks.