COVER GP-VALVE MECHANISM 3929460 - Caterpillar

Benefits of the Pink PTFE Coating
The primary benefit of the coating is a reduction in hose and tube assembly leaks due to incorrect installation of the O-ring face seal. The coating lowers the friction between the seal and the fitting groove. Lower friction helps to prevent twisting that may occur during the insertion of the seal into the groove. If twisting occurs, the seal may not seat properly in the groove. This will cause the seal to leak.Another benefit of the coated seal is the fact that lubrication is not required. When a service technician lubricates a seal, there is an increased chance of introducing contamination to the system from the lubrication. This can cause serious damage to the hydraulic system.The pink color also allows the service technician to easily notice that there is a missing seal during installation of the hose or the fitting.Additional Benefits of Genuine Caterpillar O-ring Face Seals
There are two unique design features of Caterpillar O-ring face seals. The inside and the outside diameters are slightly larger than the industry standards. In addition, the tolerance for the outside diameter is about 50% smaller than the industry standard. These features provide a consistently tighter fit between the seal and the fitting groove. This helps to ensure that Caterpillar O-ring face seals will not leak.Affected Part Numbers
Table 1
Part Number    Cross Section    Outside Diameter    
4J-5477    
1.78 mm (0.07 inch)    
11.23 mm (0.44 inch)    
6V-9397    
1.78 mm (0.07 inch)    
12.83 mm (0.51 inch)    
6V-8398    
1.78 mm (0.07 inch)    
16.03 mm (0.63 inch)    
7J-9108    
1.78 mm (0.07 inch)    
19.28 mm (0.76 inch)    
6V-9746    
1.78 mm (0.07 inch)    
22.50 mm (0.89 inch)    
5K-9090    
1.78 mm (0.07 inch)    
27.22 mm (1.07 inch)    
6V-8400    
1.78 mm (0.07 inch)    
33.57 mm (1.32 inch)    
8T-0315    
1.78 mm (0.07 inch)    
41.54 mm (1.64 inch)