Enerpac GBJ-Series User Manual

Page 5

CAUTION: DO NOT OVERFILL! With ram fully
retracted and jack in upright position, oil level
should not be higher than shown in Fig. 6 or

Fig. 7 (as applicable for your jack model).

5. Reinstall oil fi ll/air release plug.

6. Bleed air as described in Section 6.2.

6.2 Air Bleeding

The following procedure should be performed after
adding oil and whenever a “spongy” feel is noticed
during jack operation.

To remove air from the jack:

1. Using rectangular end of pump handle, turn the

release valve stem counter-clockwise to open valve
(do not turn more than two revolutions).

2. Insert pump handle into handle socket. Operate

handle 6 to 8 strokes.

3. Using rectangular end of pump handle, turn the

release valve stem clockwise until valve is fully closed.

4. Insert pump handle into handle socket. Operate

handle until ram is fully extended.

5. Operate pump handle an additional 5 to 6 strokes.

6. Using rectangular end of pump handle, turn the

release valve stem counter-clockwise to open valve
(do not turn more than two revolutions).

7. Push the ram all the way down until it is fully retracted.

8. Using rectangular end of pump handle, turn the

release valve stem clockwise until valve is fully
closed. Do not overtighten!

9. All models except GBJ-100: Using ﬁ ngers, push the

rubber oil ﬁ ll/air release plug to the side to release
any trapped air.

10. Model GBJ-100 only: Loosen oil ﬁ ll/air release plug

1 to 2 turns to release any trapped air. Tighten plug
after releasing air.

6.3 Inspection

Visually inspect the jack before each use. Remove the
jack from service immediately and take corrective action
if any of the following problems are found:

a. Cracked or damaged housing.

b. Excessive wear, bending or other damage.

c. Leaking hydraulic ﬂ uid.

d. Scored or damaged piston rod (ram).

e. Incorrectly functioning extension screw.

f. Loose hardware.

g. Modiﬁ ed or altered equipment.

WARNING: If the jack appears damaged in any
way and/or shows signs of malfunctioning, it
must be immediately removed from service. The

jack must remain out of service until it has been inspected
and repaired by an Enerpac Authorized Service Center or
other qualiﬁ ed hydraulic service facility.

6.4 Periodic Maintenance

Thoroughly lubricate all pivot pins and linkages with
lubricating oil before using the jack and after every 10
ram up/down cycles. See Fig. 8.

Fig. 8 - Lubrication

OIL

Periodically check the ram for signs of corrosion. Clean
as needed and wipe with an oil saturated cloth.

7.0 STORAGE

Before storing the jack:

• Push the ram all the way down, so that it is fully

retracted and protected from damage and corrosion.

• Be sure that extension screw (if equipped) is turned

all the way down to protect the threads from damage.

• Wipe off any dirt or oil.

• Be sure that the release valve is fully closed.

Always store the jack in the upright position, in a
protected location where it will not be exposed to
corrosive vapors, abrasive dust or any other harmful
elements.

8.0 TRANSPORTING AND POSITIONING THE JACK

• Models GBJ-002 through GBJ-050: These models can

be transported and positioned by hand, without use of
an auxiliary lifting device. For added convenience, a
lifting handle is provided on models GBJ-020, GBJ-
020S, GBJ-030 and GBJ-050.

• Model GBJ-100: This model must be transported and

positioned using a hoist or other auxiliary lifting device
of appropriate capacity. Attach the lifting device hook
to the jack lifting handle.

Note: Models GBJ-020 through GBJ-100: Refer to
Fig. 2 for location of jack lifting handle (item #11).