Allmand Brothers Allmand 7.5 FT BACKHOE - Manual (Page 11)

11
SERVICE
CYLINDER SERVICE
Cylinders are designed to be reliable and easy to service. If a
cylinder should malfunction during warranty period, return
complete cylinder assembly, without disassembling, to your
authorized service department or contact your authorized service
department for instructions. Unauthorized disassembly of a
cylinder in warranty period will VOID WARRANTY.
Following is an outline procedure for disassembling and
reassembling cylinders.
CYLINDER
1. Hold cylinder tube (13 figure 6A) stationary and pull wire
ring (14) out through slot. Rotate head (6) to ease disassem-
bly.
2. Pull shaft (1), with all assembled parts, out of cylinder
tube.
NOTE: Resistance will be felt until piston seal (10) slides over
wire retaining ring groove. Seal is usually damaged when
cylinder is disassembled
.
3.
Remove lock nut (12) from end of shaft and slide piston (9)
and cylinder head (6) off shaft.
4. Remove piston wear ring (11), piston seal (10), and o-ring
(8) from outside grooves on piston (Swing cylinders have
additional steel ring between piston and nut).
5. Remove wiper seal (2), rod seal (3) and wear ring (7) from
inside of cylinder head and o-ring (5) with backup washer
(4) from groove on outside of head.
6. Clean all parts including cylinder tube, in a suitable cleaning
solvent, and then use air pressure to blow any dirt or excess
solvent from all parts.
7. Examine all parts for wear or damage and replace, if
necessary.
CYLINDER ASSEMBLY
NOTE: Be careful not to damage seals and o-rings on edges or
holes in cylinder tube. Inspect and remove burrs and sharp edges
if necessary before reassembly.
1. Place rod seal (3) into groove inside cylinder head.
NOTE: Lips of seal (3) must face inward and seal must be firmly
seated in groove (Figure 6B). For easier installation, place seal
(3) in 120°F water to warm seal.
2. Install wiper seal (2) with lip of seal facing out and flush
with top of cylinder head. Install wear ring (7) inside other
end of head.
3. Place o-ring (5) with back-up washer (4) in groove on
outside of head. Back-up washer must be on rod side.
4. Remove sharp edges on outer edge of threaded end of shaft
(1). Lubricate wiper seal (2) and rod seal (3) in head and
carefully slide head onto shaft.
5. Place o-ring (8), piston seal (10) and piston wear ring (11)
in grooves on outside of piston.
NOTE: For easier installation, place piston seal (10) in 120°F
water to warm seal.
6. Slide piston onto threaded end of shaft and install lock nut
(12). Swing, bucket and stabilizer cylinders, tighten lock nut
(12) to 300 ft. lbs. Lift and dipperstick cylinders tighten
lock nut (12) to 375 ft. lbs. on lift cylinders.
7. Lubricate piston wear ring (11) and piston seal (10) on
piston, o-ring (5) and backup washer (4) on head and inside
of cylinder tube (13), then carefully slide piston and head
into cylinder tube.
Insert wire retaining ring (14) into slot in cylinder tube (13).
Apply pressure to wire ring to thread it into groove while
turning cylinder head.