GROVE 4-45
CD3340B/YB4411 HYDRAULIC SYSTEM
Published 04/07/2015 Control # 569-00
1. Put the ports of the cylinder down to drain the oil from
the cylinder.
2. Fasten the base of the cylinder in a vise with soft jaws.
Place a support under the rod so the cylinder is level.
3. Use a spanner wrench to loosen and remove the head
gland. Slide the head gland forward on the cylinder rod.
4. Pull the cylinder rod and piston straight out of the
cylinder tube. If the cylinder and piston are hard to
remove, install the head gland back into the cylinder and
apply shop air to the base port to push the piston out to
the head gland.
5. Fasten the eye of the rod in a vise with soft jaws. Put a
support under the opposite end of the rod to hold the rod
level. Use care not to cause damage to the chrome
surface of the rod.
6. The piston is fastened to the rod either by internal
threads or with a locking nut. To remove the piston:
a. On pistons with internal threads, remove the set
screw from the piston. Use a spanner wrench to
loosen and remove the piston.
b. On pistons which are fastened with a locking nut,
use a socket wrench to loosen the nut.
7. Remove and discard the seals and wear rings from the
piston.
8. Remove and discard all seals, backup rings, wear rings,
etc. from the head gland.
Inspection
Wash the parts in a suitable solvent. Use compressed air to
remove all residue and dry.
Check the bore of the cylinder tube for damage or distortion.
Move the piston through the full length of the cylinder and
check the clearance between the piston and the bore of the
cylinder. If there is damage or distortion, replace the cylinder
tube.
Look for damage to the chrome surface of the rod. The rod
must be smooth and straight. A bent rod indicates possible
loss of strength in the rod and replacement is necessary. If
the chrome surface has damage, completely remove the old
chrome and apply new chrome 0.03 mm (0.001 in) thick.
Assembly
1. Install new rings, rod wiper and seals on the head gland.
See cylinder illustrations for location and correct
installation.
2. Apply hydraulic oil to the rod and slide the assembled
head gland on the rod.
3. Assemble the rings and seals on the piston.
4. Be sure O-ring is installed between the piston and the
rod. Fasten the piston to the rod with locking nut and
tighten to the specified torque. On pistons with internal
threads, apply Loctite 243 to the threads and screw
piston onto cylinder rod and torque in place.
5. Apply hydraulic oil to the bore of cylinder and the rings
on the piston. Carefully slide the piston and rod into the
cylinder tube. Keep the rod straight during installation.
Use care not to damage the piston rings when you move
the piston past the threads in the bore of the cylinder
tube.
6. Slide the head gland into the cylinder tube and tighten to
the specified torque. See illustrations. If equipped, install
the set screw to secure the gland head in the cylinder.
Test
1. Fill the cylinder with clean hydraulic oil. Test to pressure
in both directions as directed in steps 2 through 5.
Table 4-10
2. Move the cylinder rod through two complete strokes at
5510 kPa (800 psi) to remove air from the cylinder. Look
for external leaks. If the pressure difference between
cylinder ports is more than 689 kPa (100 psi) during the
second stroke, the cylinder assembly is not acceptable.
Disassemble and inspect for foreign materials or wrong
assembly.
3. Wipe the cylinder rod clean, then move the cylinder
through four complete strokes at 5510 kPa (800 psi), but
do not permit the cylinder to hit bottom on each stroke.
After four strokes, extend the cylinder rod just far
enough to see how much oil has collected during the
four strokes. Inspect the cylinder rod for indication of rod
seal leakage. A thin layer of oil on the cylinder rod is
normal.
4. Fully retract the cylinder rod. Keep the base port open.
Apply test pressure (Table 4-10) to the rod port. Hold this
WARNING
Flying Parts Hazard!
If air or hydraulic pressure is used to force out the piston
assembly, ensure that the head gland is securely installed
in the cylinder tube.
Cylinder Test Pressure
Lift 34474 kPa (5000 psi)
Telescope 34474 kPa (5000 psi)
Horizontal Outrigger 24131 kPa (3500 psi)
Vertical Outrigger 24131 kPa (3500 psi)
Reference Only
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