SECTION 4 - BASIC HYDRAULIC INFORMATION & SCHEMATICS
31215079
4-31
10. Inspect threaded portion of head for damage. Dress
threads as necessary.
11. Inspect seal and o-ring grooves in head for burrs and
sharp edges. Dress applicable surfaces as necessary.
12. Inspect cylinder head outside diameter for scoring or
other damage and ovallity and tapering. Replace as
necessary.
13. If applicable, inspect rod and barrel bearings for
signs of correct excessive wear or damage. Replace
as necessary.
a. Thoroughly clean hole, (steel bushing) of burrs,
dirt etc. to facilitate bearing installation.
b. Inspect steel bushing for wear or other dam-
age. If steel bushing is worn or damaged, rod/
barrel must be replaced.
c. Lubricate inside of steel bushing with WD40
prior to bearing installation.
d. Using an arbor of the correct size, carefully
press the bearing into steel bushing.
NOTE:
Install pin into the Gar-Max bearing dry. Lubrication
is not required with nickel plated pins and bearings.
14. Inspect travel limiting collar or spacer for burrs and
sharp edges. If necessary, dress inside diameter sur-
face with Scotch Brite or equivalent.
15. If applicable, inspect port block fittings and holding
valve. Replace as necessary.
16. Inspect the oil ports for blockage or the presence of
dirt or other foreign material. Repair as necessary.
17. If applicable, inspect piston rings for cracks or other
damage. Replace as necessary.
Assembly
NOTE:
Prior to cylinder assembly, ensure that the proper cyl-
inder seal kit is used. See your JLG Parts Manual.
Apply a light film of hydraulic oil to all components prior
to assembly.
1. A special tool is used to install a new rod seal into the
applicable cylinder head gland groove.
WHEN INSTALLING ‘POLY-PAK’ PISTON SEALS, ENSURE SEALS ARE
INSTALLED PROPERLY. REFER TO WIPER SEAL INSTALLATION FOR
CORRECT SEAL ORIENTATION. IMPROPER SEAL INSTALLATION COULD
RESULT IN C YLINDER LEAKAGE AND IMPROPER C YLINDER OPERA-
TION.
WHEN INSTALLING THE WIPER SEAL ON THE LOWER (TOWER) LIFT
CYLINDER, APPLY HIGH STRENGTH THREADLOCKING COMPOUND ON
THE WIPER SEAL IN THREE EVENLY SPACED PLACES TO AID IN RETEN-
TION OF THE SEAL.
2. Use a soft mallet to tap a new wiper seal into the
applicable cylinder head gland groove. Install a new
wear ring into the applicable cylinder head gland-
groove.
STEEL
BUSHING
COMPOSITE
BUSHING
ARBOR
Figure 4-18. Bushing Installation
Figure 4-19. Rod Seal Installation
Figure 4-20. Poly-Pak Piston Seal Installation
Go
to
Discount-Equipment.com
to
order
your
parts
