EDGE AS- 2174699 - Caterpillar

Rework Procedure
Hydraulic Tank Crack Repair
Refer to the following document to reference general welding procedures and guidelines for repairing hydraulic tank cracks on 990H machines.
Special Instruction, REHS1841, "General Welding Procedures".Remove the hydraulic tank from the machine. Before performing welding on the inside or outside of the tank, clean the tank of combustible or flammable materials. The repair can be made utilizing SMAW or GMAW. For the SMAW process:
Use a 1/8" 7018 low hydrogen electrode. Completely de-slag welds and visually inspect for under-cut, porosity, and visible discontinuities. For the GMAW process:
Use an ER70S-3 (for example, Lincoln Electric L-50) electrode, 90AR/10CO2 gas, 27.5 – 29 V, 360 IPM WFS.Expansion Tank Installation
Follow the below guidelines for the installation of the 235-1290 Expansion Tank Gp on 990H machines.
Ensure that machine implement is lowered to ground and steering articulation lock is installed.
Relieve pressure from the implement/brake tank by depressing the plunger on the tank breaker relief valve.
Relieve pressure from the fan/steering tank by depressing the plunger on the tank breaker relief valve.
Remove the tank breaker relief valves from the implement/brake tank and the fan/steering tank.
Remove the 212-8787 Cover As and this component will be replaced with 221-3990 Cover As (17). Reference 234-4920 Platform Group in Parts Manual, SEBP3850 for location.
Illustration 1 g03329786
Install 148-8347 Elbow As (3) in the fan/steering tank breather port. Install 148-8455 Union As (2) with 2P-1293 Locknut (1) .
Illustration 2 g03329844
Install 106-8715 Elbow As (4) in the implement/brake tank breather port.
Illustration 3 g03329857
Install 218-4480 Hose As (10), 221-3498 Hose As (8), and 221-3499 Hose As (9). Use three 4S-4455 Clips (5), 8T-4121 Hard Washers (6), and 8T-4136 Bolts (7) .
Install 153-6237 Elbow As (11) into the ports on the 235-1281 Expansion Tank As (12). Install the 235-1281 Expansion Tank As (12) and 221-3990 Cover As (17). Refer to Disassembly and Assembly, RENR8826 for the assembly and installation procedure.
Illustration 4 g03330017
Install 167-1795 Elbow As (14) and 358-9475 Breaker Relief Valve As (15) on the implement/brake tank in the location that is shown in Illustration 4.