14
JH INDUSTIRES INC.
bucket under the tank and remove the drain
plug. Allow the entire contents of the tank to
drain into the bucket.
4. Refer to
FIGURE #12
for correct hydraulic oil.
Replace the drain plug and fill the hydraulic tank
with oil.
5. Remove all lock-out, tag-out and cycle the dock
lift 3-4 times to remove all air from the hydraulic
system. Bring the dock lift to its lowered position
and check the level of the hydraulic oil. Make
sure the oil is to the top of the sight on the side
of the tank.
Hydraulic Seals:
Generally, the seals are Buna-N-Nitrile and
poly-urethane. The hoses are braided wire type.
Always consult factory regarding special fluids
rather than make assumptions on your own.
Hydraulic Cylinder Maintenance:
CYLINDER REMOVAL
1. Raise the lift table to full raised position.
2. Follow instructions to prepare dock lift for main-
tenance (see pg. 11-12 this manual) .
3. Disconnect the hydraulic hoses from the cylinder
and
cap
the
hose
ends
to
prevent
contamination.
4. At the upper cylinder pin location a keeper plate
held on with two 3/8”-16 socket head bolts
needs to be removed first. (See
FIGURE #14
)
Next slide the chrome rod out (do not damage
chrome finish) while supporting the cylinder in
place. Do the same to the lower cylinder pin
location (if applicable).
5. Remove the cylinder from the lift, being careful
not to damage the surface finish of the cylinder
rod.
6. Place the hose connection end of the cylinder in
a container or bucket and force the cylinder
closed to remove all hydraulic fluid from cylinder.
If the dock lift is equipped with multiple cylinders it is
recommended to rebuild all cylinders at the same
time. Seals generally wear at the same rate, if you
only rebuild one cylinder, you may have to pull the
lift out of service soon thereafter to do the others.
FIGURE #14-
Cylinder Pin Removal
CYLINDER DISASSEMBLY
1. Secure the cylinder on a work bench. (Do not
use a vise or clamp on the cylinder housing, this
could damage the housing.
2. Remove the snap ring retaining the cylinder
gland. (See
FIGURE #
)
3. Carefully pull out the entire rod, gland and piston
assembly.
4. Remove the hex lock nut retaining the piston,
then slide the piston off the rod. (Be sure
components are placed on a clean surface to
avoid contamination.)
5. Carefully inspect the entire housing with a
flashlight, looking for any evidence of rust,
scratches or surface blemishes. Small
blemishes may be removed with fine emery
cloth and larger faults will require the use of a
hone. Thoroughly clean the housing before
reassembling to avoid contamination.
6. Remove all old seals and wear rings. Clean the
piston, rod and gland. Inspect for any possible
damage and replace if necessary.
CYLINDER REASSEMBLY
1. Reinstall new seals and wear rings, use some
lubricant to aid in ease of assembly. See
FIGURE #
for correct seal placement and
direction.
MAINTENANCE,
CONTINUED
NOTICE!
Cylinder
rod
Keeper Plate
Socket Head
Cap Screw
Upper Cylinder Pin
Summary of Contents for Copperloy
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