Checking The Boom Cylinder - NRC 30CS Operation And Maintenance Manual

5.2

Checking the boom cylinder

You need to check the boom cylinder if the boom:
Retracts by itself when lifting a (heavy) load with the winches.
l
Extends by itself when lifting a load on the underlift. The underlift tilts down when the
l
boom extends.
The problem might be due to a leaking piston, damaged seal or broken cartridge in the lock
valve block.
The following troubleshooting procedure isolates a boom cylinder and checks it for leaks. If you
push oil onto one side of a cylinder and the other side is vented, no oil should leak unless there
is a broken piston, damaged seal or broken cartridge.
NOTE: You will need a load (e.g. another vehicle) for this procedure.
1. Lower the underlift completely.
2. Choose a lifting point on the vehicle to be towed. It must be both strong enough and have
enough clearance for the underlift to move.
Using a poor lifting point may damage the towed vehicle and wrecker or even
cause a serious accident.
3. Use the safety chains and tensioner to hold the vehicle in place on the underlift's T-bar.
4. Fully retract the boom and keep it retracted using a winch cable hooked to the D-ring on
the wrecker.
5. Stop the hydraulic system.
Composite Slider Wreckers – Operation and Maintenance
Models: 30CS-40CS-50CS
O p e r a t i o n a n d M a i n t e n a n c e
132
REV. 1
APRIL 12, 2023