Fill And Bleed Instructions; Troubleshooting - Cherry GH-702A Maintenance Manual

FILL AND BLEED INSTRUCTIONS

To replace a small amount of oil in the tool, remove cap screw (15), attach the Cherry air bleeder (700A77), connect the tool to the
air line and cycle several times. This will ensure the removal of any air from the hydraulic system and its replacement with fluid.
Should it become necessary to completely refill the tool (such as would be required after the tool has been dismantled and re-
assembled), take the following steps:
(15)

TROUBLESHOOTING

Check the air line for correct pressure at the tool. It
1.
must be 90 to 110 psi (6.2 to 7.6 bar).
Check the tool for lack of oil (see Fill and Bleed
2.
instructions).
Check for oil leakage:
3.

Oil leaking around the cap screw (15) in the head
indicates that the screw is loose or the Stat-O-Seal
(14) needs replacing.

If oil should leak through the by-pass hole at the
base of
the handle (32) the 0-rings (34) are worn or
damaged.

Oil leaking from the front of the head (1) indicates
that 0-rings (2) are worn or damaged.
4. Check for excessive air leakage from the air valve:

If spring (39) is broken or dislodged, air will
bleed directly through the bottom of the air valve
and the head piston retreats to its full stroke
without returning. See air valve instructions on
page 5.

If 0-ring (44) on plug (45) is worn or damaged,
replace.

If 0-rings (36) on valve spool (41) are worn
or damaged, replace.
1. Remove head assembly (1) from handle (32) by
unscrewing cap screws (50).
2. Fill handle assembly (32) with the recommended oil to
within 1/8" (3.175mm) of the top of the handle casting.
3. Place head assembly (1) on handle (32), being sure
gasket (49), and 0-ring (48), are properly in place.
Tighten cap screws (50) uniformly to prevent leakage
around gasket.
4. Remove cap screw (15) and attach the Cherry air
bleeder (700A77). Connect the tool to the air line and
cycle a number of times. This will ensure the removal of
any air from its hydraulic system and its replacement
with fluid.
5. Check movement of the head piston (4). If it does not
move freely or is slow in operation:

0-rings (2), (5), (7) and (8) may be damaged and
require replacement.

Head piston (4) may be mechanically locked
due to damaged parts.

The 0-ring (36) on power piston rod (37)
may be damaged; replace.

Muffler (46) or air filter (42) inside valve spool (41)
may be plugged with dirt. Clean them thoroughly
with normal solvent and back-blow with compressed
air.

Hole in metering screw (43) in valve spool (41)
may be blocked or damaged. Hole diameter should
be .028" (.711 mm). Clear and size or replace
valve spool assembly (40).
6. Rivet stem sticks in the pulling head:

Pulling head components need maintenance.
Disassemble the pulling head, clean and replace
worn parts. Re-assemble following instructions on
page 7.

Spent rivet stems are wedged side by side in the
pulling head. Disassemble the pulling head, remove
stems and re-assemble following the instructions on
page 7.
4