GASKET 0992150 - Caterpillar

Solution
If the 188-4167 Plate or the 188-4166 Plate in the 204-2679 Swing Motor Gp fail, make sure that the case drain pressure is within functional specifications.
Illustration 1 g01286338
Top View Of A Swing Motor (A) Inlet port or outlet port (B) Make up port (C) Drain portThe typical case drain pressure is less than 70 kPa (10 psi). The maximum allowable case drain pressure is 200 kPa (29 psi). The maximum allowable case drain pressure is measured at the swing motor during stall condition of the swing motor or the travel motor. A fracture of the retaining plate in the swing motor and deformation of the spring plate in the swing motor can occur if the case drain pressure exceeds 2 MPa (290 psi).Measure the case drain pressure in order to make sure that the pressure is within functional specifications and that the hydraulic lines are not clogged. Refer to Testing and Adjusting, "Travel Motor - Test Measurement of Case Drain Oil" in the service manual that is appropriate for your machine. Replace the travel motors that are not within specifications.
Illustration 2 g01286339
Swivel Joint (D) Seal (E) O-Ring SealMake sure that the seals in the swivel joint are inspected for damage if the travel motor or the swing motor has failed. Refer to Illustration 2. The swing motor may fail again if the seals in the swivel joint are damaged. The seals must be replaced prior to reassembly of the swing motor. The swing motor may also fail again if the case drain pressure is not within the specification.Procedure For The Measurement Of The Case Drain Pressure For The Swing Motor
Table 1
Required Parts    
Item    Qty    Part Number    Description    
1     1     7X-0871     Tee    
2     1     6V-3965     Fitting As    
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "Hydraulic System Pressure - Release".
Illustration 3 g01286218
Location Of The Drain Hose (G) Drain hose
Illustration 4 g01286219
Disassembly Of The Drain Hose (C) Drain port
Disassemble drain hose (G). The drain hose is the hose between the drain port in the swing motor and the swivel joint. A pressure measuring port is installed between the drain port for the swing motor and the drain hose.
Illustration 5 g01286225
Tee and fitting assembly (1) 7X-0871 Tee (2) 6V-3965 Fitting As
Assemble the tee and fitting assembly.
Illustration 6 g01286227
Pressure measuring port for the swing motor
Assemble the pressure measuring port on the swing motor. Assemble the drain hose (G) and the tee.
Measure the case drain pressure during operation of the swing function.