LOAD KING 35-127 M, Operator'S Manual

Page: 186 / 216

186
35-127 M
Service / Parts
Lift Cylinder
HOW TO ANALYZE TOPPING PERFORMANCE
The lift cylinder should hold up the boom and load with a minimal amount of drop-off� The cylinder is
equipped with a counterbalance type holding cartridge in the base of the cylinder�
DO NOT REMOVE THE CARTRIDGE IN THE BASE END OF THE TOPPING WITHOUT
THE BOOM BEING UNLOADED AND IN A SUPPORTED CONDITION� REMOVING
THE CARTRIDGE WITH THE BOOM IN AN UNSUPPORTED CONDITION WILL
CAUSE THE BOOM TO DROP INSTANTLY AND UNCONTROLLABLY�
TRAPPED PRESSURE IN CYLINDER CAN FORCEFULLY EJECT CARTRIDGE�
MAKE SURE PRESSURE IS RELIEVED BEFORE REMOVING A CARTRIDGE�
NEVER STAND BEHIND A CARTRIDGE WHILE REMOVING IT�
To test the cylinder for holding, the following procedure should be used:
NOTE:
With the outriggers extended, mark each outrigger leg. These marks should be checked at
the end of the test procedure below to determine if any outrigger is the cause of the movement
noted.
With the boom fully retracted and at a 50-60° angle, attach a weight equivalent to the rated load and
raise the load 2 feet off the ground� Accurately measure and record the distance from the ground� Shut
off the engine and move the control levers to release the hydraulic pressure trapped in the hoses� The
load should not drop more than 1/2” in 10 minutes� If it drops more than the amount allowed, the
following troubleshooting steps should be performed:
A leaking cylinder will generally fall into 2 categories:
1� External leaks (usually found around the base of the cylinder)�
A� RCI system sense line hose and fittings�
B� End casting welds�
C� Cartridge O-Rings�
D� Cross-drilled passages and plugs�
2� Internal leaks (bypassing within the cylinder or holding cartridge)� There are two things that must
be checked in order to isolate the source of the leakage:
A� Holding cartridge
Attach a weight equivalent to the rated load and raise the boom 2-3 inches off the boom rest�
Remove both topping hoses at the control valve� Oil coming from the boom-up hose
indicates a bypass at the counterbalance cartridge� Replace or clean the cartridge� Boom
must be unloaded and supported before cartridge is removed�
B� Piston bypassing from base side to rod side
If oil comes out of the boom-down hose while still engaged in the same test, the cylinder is
bypassing internally and will require internal repairs�