Manitowoc 999 Service And Maintenance Manual

Reference Only
TROUBLESHOOTING 999 SERVICE/MAINTENANCE MANUAL
10-58
Published 05-16-17, Control # 233-03
Test 26 – Adjusting the Counterbalance Valves
Each jacking cylinder has a single counterbalance valve at
the piston end of the cylinder. The retract adjusting screw at
the valve provides adjustment for each jacking cylinder load
support. The extend adjusting screw allows cylinders to be
adjusted for uniform operation on level ground.
Counterbalance valves are pre-adjusted at the factory, but
are not calibrated. Adjust counterbalance valves with a
closed-end wrench and hex wrench.
To avoid over-adjusting the cylinders, use a hex wrench as a
guide and never turn a counterbalance valve more than 1/2
turn in either direction.
To adjust a counterbalance valve:
1. Loosen the adjusting lock nut.
2. Rotate counterbalance-adjusting screw 1/2 turn
clockwise (in) to lower holding pressure.
3. Rotate counterbalance adjusting screw 1/2 turn counter-
clockwise (out) to raise holding pressure.
4. While holding counterbalance-adjusting screw with hex
wrench, tighten lock nut.
5. Recheck cylinder(s) for correct load support and uniform
operation.
Item Description
1 Counterbalance Valve
2 Gantry Cylinder
3 Jacking Cylinder
2
P1617 P1527
1
3
1
CAUTION
Possible Component Damage!
Special instructions and warnings apply when adjusting
the gantry and boom cylinder counterbalance valves as
specified in Shop Procedures
in Section 2. This
procedure MUST be followed carefully to ensure
adjustments are performed safely. The gantry cylinders
will not extend evenly without counterweights attached to
crane. All gantry cylinder adjustments must be performed
with counterweights installed.

Manitowoc 999 Specifications

General

Brand	Manitowoc
Model	999
Category	Construction Equipment
Language	English