SWITCH AS 3932235 - Caterpillar

Be sure no one is under or near the implements before manually lowering the boom. Keep all personnel away from the boom drop area when lowering the boom with the engine stopped in order to avoid possible personal injury
Relieve the pressure in the hydraulic system before manually lowering the boom. Move the hydraulic control lockout lever to the UNLOCKED position. Move the travel levers/pedals forward and backward in order to relieve the pressure.
Open the hood. Refer to Operation and Maintenance Manual, "Hood Tilt" for the procedure.
Press the hydraulic tank breaker relief valve in order to relieve any tank pressure.
Illustration 1 g00791064
Main Control Valve (1) Control valve (boom).
Illustration 2 g00791080
View A-A (2) Flow limiter valve (boom up). (3) Screw. (4) Nut.
Measure the external thread length of screw (3). Record the external thread length of screw (3) from the face of nut (4) to the end of screw (3) .
Loosen nut (4) .
Remove screw (3) with nut (4) as one assembly.
Install one M12 bolt into flow limiter valve (1) .
Turn the bolt clockwise until you feel contact between the bolt and the valve spool.
Slowly turn the bolt clockwise until the boom is lowered.
Remove the bolt.
Install screw (3) with nut (4) .
You must reset the flow limiter valve for the boom up after you perform this procedure. Use the measurement from Step 112. Refer to Testing and Adjusting, RENR6051, "Cycle Times - Test and Adjust" for the confirmation of the correct boom raise cycle time.