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TM 10-3930-671-24
10.
Excessive fork drift indicates faulty or worn lift
cylinder
seals.
Remove
lift
cylinder(s)
for
inspection and repair, as necessary.
Upright Maintenance
It is recommended to perform the following service
maintenance at every truck PM, or as otherwise
specified.
1.
Inspect the upright assembly: rails, carriage
rollers, lift chains, and lift and tilt cylinders.
a)
Look
for
obvious
wear,
maintenance
problems, and damaged or missing parts.
b)
Inspect all lift line hydraulic connections for
leaks.
c)
Check the cylinder seals for leaks.
d)
Check the lift cylinder rods for wear marks,
grooves, and scratches.
e)
Check for any loose parts or fittings.
Check for any damaged or loose rollers,
and rail wear. Check for metal flaking in
the roller pathways.
f)
Carefully inspect the lift chains for wear,
rust and corrosion, cracked or broken
links, stretching, etc.
g)
Check that the lift chain anchor fasteners
and locking means are in place and tight.
h)
Check that the lift and carriage chains are
correctly adjusted to have equal tension.
2.
Be sure all safety guards and chain retainers are
in place and not damaged. Inspect the carriage
stops and cylinder retainer bolts. Check all
welded connections.
3.
Check for interference of hoses, chains, etc.,
during lift operation.
4.
Check lift chain adjustment and adjust fork
height to prevent fork wear.
5.
Inspect
and
lubricate
lift
chains.
During
inspection, check for a layer of oil on the external
chain surfaces.
6.
Check upright trunnion bearings for wear. Check
trunnion brackets for cracks or damage. Check
upright trunnion cap bolts for correct torque and
that no bolts are missing.
7.
Check
upright
mounting
bracket
fasteners.
Tighten each bolt to correct torque specification.
8.
Keep piston rods and tops of cylinders clean.
9.
Always keep piston rods in retracted position
when upright is not in use.
10.
When operating in corrosive environments,
inspect the lift chains every 50 hours.
11.
Perform upright shim inspection at least every
500 hours of operation
This section describes procedures which can produce
unexpected movement of the upright rails and other
parts.
•
Do not walk or stand under raised forks.
•
Keep clear of load and carriage when making
any checks and adjustments.
•
Keep your arms and fingers away from moving
parts of the upright.
•
Do not reach through upright open areas.
•
Review all described procedures before starting
any maintenance or service function. Failure to follow
this warning can result in serious injury.
Lift Chain Maintenance
Lift chains are very important components of fork lift
trucks. The chain system on your upright was designed
for safe, efficient, and reliable transmission of lifting force
from hydraulic cylinder to the forks. Safe use of your
truck with minimum down time depends on the correct
care and maintenance of the lift chains. Most complaints
of unacceptable chain performance are a result of poor
maintenance. Chains need periodic maintenance to give
maximum service life.
Lift Chain Lubrication
The most important consideration in field maintenance of
lift chains is lubrication. The lift chains operate under
heavy loadings and will function more safely and have
longer life if they are regularly and correctly lubricated. It
is very important to protect lift chains from corrosion,
whether in service or in storage, because corrosion will
reduce the load carrying capacity. There must be a layer
of oil on the chains at all times. Heavy motor oil may be
used as a lubricant and corrosion inhibitor.
Chain lubricant should be applied in a manner such that
the lubricant penetrates into the chain joints to prevent
wear. Lubricate the full length of all strands.
1. Inspect and lubricate the lift chains every truck
PM.
2. Under some operating conditions, e.g. in very
dirty or corrosive environments, it may be
necessary to inspect and lubricate the chains
between PMs.
3. Use lubricant as specified in Lubrication Order
(Refer to Appendix E).
F-498
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