Changing the Pressure Reducing Valve Lowers the Risk for Leaks to Occur in the Brake Control Valve Group on Certain 988K Wheel Loaders {4264, 4265, 4282, 4293} Caterpillar

Wheel Loader

988K (S/N: LWX1-693; TWX1-933)

Description Of Change: Installation of the new pressure reducing valve will lower noise and resonance levels in the hydraulic system, which will allow for better sealing in the brake control valve.

Adaptable To:

Illustration 1	g06113719
(1) 263-3891 Plug As

Illustration 2	g06113723
(2) 388-6321 Brake Control Valve Gp

Illustration 3	g06113732
(3) 488-2889 Pressure Reducing Valve

In the event of leakage in the cab from the 388-6321 Brake Control Valve Gp, replace with new 388-6321 Brake Control Valve Gp (2). Replace 369-8183 Pressure Reducing Valve with 488-2889 Pressure Reducing Valve (3). Remove the 423-1880 Sequence Valve Gp and replace with the 263-3891 Plug As (1) on machines S/N:LWX1-520, and ; S/N:TWX1-387.

In the event of leakage in the cab from the 388-6321 Brake Control Valve Gp, replace with new 388-6321 Brake Control Valve Gp (2). Replace 369-8183 Pressure Reducing Valve with 488-2889 Pressure Reducing Valve (3) on machines S/N:LWX521-693, and ; S/N:TWX388-933.

Note: The improved pressure reducing valve is effective on machines S/N:LWX694-UP and ; S/N:TWX934-UP.

Reference: Refer to Service Magazine , M0068498 , "An Improved Pilot Pressure Reducing Valve Cartridge And Cavity Plug Are Now Available For 988K Wheel Loaders, 834K Wheel Dozers, and 836K Landfill Compactors {4264, 4293}" to replace 263-3891 Plug As (1) and 488-2889 Pressure Reducing Valve (3).