Upright ULII-25, Service & Parts Manual

Page: 34 / 113

4-12
Maintenance
Section
UL-25/32/40/48 Portable Personnel Lifts
4.6
4.6 Cylinder Assembly (Cont.)
ORIFICE VALVE CLEANING
Using a suitable lifting device, lower the work platform
into a horizontal position (Figure 4-5). If possible, place
the machine onto a sturdy work table using a forklift.
Never attempt to lower lift into a horizon-
tal position without the use of a suitable
lifting device; bodily injury or damage to
the machine may result.
1. Remove cylinder mounting plate fasteners and
retaining ring.
2. Remove tie rod nuts, count the number of turns
required to bring the nut flush with the tie rod end
and record for reference during installation. The
tension on the tie rods maintains the left / right
positioning of the cylinder within the mast assembly,
reinstalling the nuts with the proper tension will
speed up adjustment later.
3. Remove the cylinder mounting plate. Be careful not
to allow the tie rods to suck back inside of the mast
assembly, replace the nuts on the tie rod ends
temporarily to prevent this.
4. Remove hydraulic line from the cylinder fitting and
cap the cylinder fitting to prevent contaminants from
entering the cylinder.
Marring the surface of the cylinder rod will
damage cylinder seals and cause leakage.
Use a strap wrench to prevent rod damage.
5. Extend cylinder rod at least twelve inches by hand.
Apply heat to rod near end cap to loosen Loc-tite®.
Wear safety glasses and heat resistant gloves
when operating torch. Do not touch hot
surfaces without proper protection.
6. Using a Strap Wrench, 62482-000, to secure the
cylinder rod, unscrew the cylinder rod end. If
necessary, thread a 9/16 x 18 bolt into end cap port
to use as a lever. Remove rod end cap and orifice /
bleeder tube assembly.
7. Remove snap ring to release orifice / bleeder tube
from rod end cap.
8. Clean orifice valve hole with a straight pin. Flush
with solvent to remove any contamination that may
remain in bleeder tube.
9. Reinstall orifice / bleeder tube into rod end cap and
secure with snap ring.
10. Replace static seal on red end. Existing seal may
have been damaged by heating rod.
11. Rod and rod end threads must be absoloutly clean.
Spray threads with Loctite
®
primer #7471, allow to
dry for five minutes. Coat threads liberally with
Loctite
®
#242. Thread rod end cap onto rod,
tighten using strap wrench to hold rod.
12. Push rod back into cylinder for reassembly.
13. Reconnect hydraulic line.
14. Remove nuts from tie rod ends and set the cylinder
mounting plate into place. Secure mounting plate
with fasteners.
15. Install tie rod nuts flush with tie rod ends, torque each
nut the exact number of turns used to remove it.
16. Reinstall retaining ring.
17. Using a suitable lifting device, raise the lift to its
normal vertical position.
18. Bleed air from cylinder by cycling the mast to full
extension several times. The cylinder is self bleeding;
air will be forced out of the cylinder during the
lowering cycle.
19. If necessary, remove pinch shield and check align-
ment of cylinder within mast assembly by peering
down the mast with a flashlight. The cylinder guide
bearings must not be touching the inside surface of
#6 mast. The cylinder may be moved left or right
by tightening the left or right tie rod nuts respec-
tively.
If cylinder is not centered, mast may "hang"
when lowering.
Keep hands clear of the mast assembly
when the pinch shield is removed for
inspection purposes; pinching injury to
hands may result .
Never operate a machine with the pinch
shield removed, except for inspection.