22 Dealer Service
51861 (Rev. 6/16/2006)
Assembly
Lubricate O-rings and seals with clean hydraulic fl uid.
Install back-up washer (3E) on rod guide (5), then
install O-ring (3F) in exterior O-ring groove of rod
guide. Install rod seal (3D) into inner groove of rod
guide with open portion of V-groove toward piston.
Place wiper ring (3C) in outer rod guide groove. Slide
rod guide assembly (5) onto rod (1). Place wear ring
(3I) in narrow groove of piston. Place piston ring (3G) in
wide piston groove.
Lightly coat rod threads with hydraulic oil and slide O-
ring (3A) over threads and into groove. Install piston (6)
onto rod (1) with wear ring on side away from rod
guide. Install lock nut (7) and torque to 175 lbs-ft.
Compress wear ring and piston seal and carefully
insert piston and rod assembly into barrel. Use care to
prevent damage while installing.
Carefully push or tap rod guide (5) into barrel (8) just
past groove inside barrel. Insert retaining ring (3B) into
groove and pull rod (1) to seat rod guide (5) against
ring. Screw spanner nut (4) into rod guide (5) using a
spanner wrench, or carefully use a punch and hammer.
Figure 15. Hydraulic Cylinder Assembly
Installing Valve
Reconnect control linkage to valve.
Control handles should be positioned with console as
shown in Figure 16.
When completing a maintenance function on the valve,
perform a functional test by placing control handles in
their various positions and make certain the correct
operation occurs corresponding to the decals on the
operator's console. Pay specific attention to the float
position of the boom. Do not operate backhoe if func-
tions differ from the decal.
If the functions differ from the decal, check to make
sure control linkage is correctly installed and check
plumbing schematics to make sure hoses are correc tly
connected.
Figure 16. Control Lever Adjustment
HYDRAULIC PUMP REPAIR
There are two suppliers approved for backhoe pumps.
They are Cessna and Sundstrand. Either type of pump
may be used to supply hydraulic pressure for the back-
hoe, but the components of the pumps are not inter-
changeable. You must determine which pump you are
repairing and obtain the correct repair parts.
Repair of the pump is limited to shaft seal replacement.
HYDRAULIC VALVE REPAIR
Valve repair should be accomplished in a clean work
place. Individual components for many of the assem-
blies are not available as repair parts. This will simplify
repair and allow you to replace complete assemblies.
Pressure Settings on Shock/Dampening Valves
Pressure settings on shock/dampening valves are pre-
set at the factory. Although they are adjustable, they
must not be reset in the field using backhoe hydraulic
1.Piston rod
3A. O-Ring
3B. Retaining ring
3C. Wiper ring
3D. Rod seal
3E. Back-up washer
3F. O-Ring
3G. Piston ring
3I. Piston ring
4. Spanner nut
5. Rod guide asy
6. Piston
7. Lock nut
8. Cylinder barrel