Baffle Assemblies May Work Loose In Hydraulic Tank Caterpillar

Problem:

The mounting tabs attached to the lower end of the 6E-0560 Baffle Assemblies may fracture. After the tabs have fractured, the two 7X-3350 Bolts, that hold the upper end of each baffle assembly, may loosen due to machine vibration. Once the bolts have loosened all the way, the entire baffle assembly will fall to the bottom of the hydraulic tank group.

Without the baffle assemblies in place, the hydraulic system is subject to damage caused by aeration, which can lead to cavitation, and/or damage caused by components of the baffle assemblies being drawn into the pump.

NOTE: The root cause of this problem is attributed to the initial failure of the mounting tabs attached to the lower end of the 6E-0560 Baffle Assemblies.

Solution:

Previously, 6E-0560 Baffle Assemblies were manufactured with a lower mounting tab that was only 2.5 mm (.098 in) thick. Now, 6E-0560 Baffle Assemblies are manufactured with a lower mounting tab that is 5.0 mm (.197 in) thick. The thicker mounting tab resists fracturing.

Check the condition of the two 6E-0560 Baffle Assemblies located inside the 122-7997 Hydraulic Tank Group on 793C (4AR1-Up, 4GZ1-Up) Off-Highway Trucks, and inside the 9T-8921 Hydraulic Tank Group on 793B (1HL1-Up) Off-Highway Trucks.

If the lower mounting tabs show no sign of failure of fracture related damage, ensure that each tab is properly secured to the tank with a 2S-0932 Washer and a 6V-7744 Locknut that has been properly tightened. Also ensure that the two 7X-3350 Bolts, that secure the top of each 6E-0560 Baffle Assembly to the tank, are properly tightened.

If the lower mounting tabs are fractured, show signs of damage, or if the dealer wishes to take preventative action, the following procedure, chart, and illustrations can be used to correct and improve the reliability of the lower mounting tabs.

1. Using 5.0 mm (.197 in) thick, SAE 1008 carbon steel, fabricate a new lower mounting tab according to Illustration 3.

NOTE: Fabricate a mounting tab for each 6E-0650 Baffle Assembly.

2. Remove the 6E-0560 Baffle Assemblies.

3. Use a grinder to remove the existing 2.5 mm (.098 in) thick mounting tab from the bottom plate of the baffle assembly. Refer to Illustration 2. To prepare for welding, clean the bottom plate of the baffle assembly where the mounting tab was removed.

4. Refer to Illustration 3 to weld the fabricated mounting tab in position on the baffle assembly. Use two 2.5 mm (.098 in) weld beads as shown in the illustration.

5. Install the repaired 6E-0560 Baffle Assemblies.

Illustration 1.

Typical Hydraulic Tank Group

(1) Two 6E-0560 Baffle Assembies

(2) Four 7X-3350 Bolts.

(3) Two 6V-7744 Locknuts.

(4) Two 2S-0932 Washers.

(5) Two Mounting Tabs.

Illustration 2.

6E-0560 Baffle Assembly (showing cutting plane X-X)

Illustration 3.

Dimensions for Fabricating Mounting Tab and Installing Mounting Tab

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