JLG 600SC_660SJC Service Manual - Manual (Page 116)

SECTION 5 - CAT CHASSIS (S/N 0300128000 TO PRESENT)
5-24 – JLG Lift – 3121157
Troubleshooting for 2-speed Controls
TROUBLES (TYPE OF FAILURE) POSSIBLE CAUSES CORRECTIVE ACTIONS
The machine does not go straight. Plunger is not shifted;
1) Foreign substances are bitten between plunger and
body.
2) Spring is not installed in place.
3) Spring is broken. - Remove foreign articles thoroughly. Repair dam-
aged parts, and reassemble the parts after cleanup. If
deep scratches or more than normal wear are found
on the parts, the parts should be replaced with new
ones.
- Install spring in proper position.
- Replace spring with new one. Then, remove foreign
articles thoroughly. Repair damaged parts, and reas-
semble the parts after cleanup. If deep scratches or
more than normal wear are found on the parts, the
parts should be replaced with new ones.
Oil leaks by abnormal wear on 2-seed control piston. Replace 2-speed control piston with new one.
Remove foreign substances thoroughly, and wash
the parts before reassembly.
2-speed control piston is not installed in place. Install 2-speed control piston in proper location.
Steel balls are excessively worn. Replace steel balls with new ones. Then, remove for-
eign articles thoroughly. Repair damaged parts, and
clean the parts before reassembly.
Orifice in oil passage of 2-speed control piston cham-
ber is different. Check for orifice diameter.
Orifice in oil passage of 2-speed control piston cham-
ber is clogged. Wash orifice before reassembly.
Plunger is installed backward. Check plunger for installing direction, and install it in a
proper direction.
Speed Two cannot be engaged. Plunger is not shifted;
Foreign substances are bitten between plunger and
body. Remove foreign articles thoroughly. Repair damaged
parts, and reassemble the parts after cleanup. If deep
scratches or more than normal wear are found on the
parts, the parts should be replaced with new ones.
Wash the orifice before reassembly.
Oil leaks due to abnormal wear on 2-seed control pis-
ton. Replace 2-speed control piston with new one.
Remove foreign substances thoroughly, and wash
the parts before reassembly.
2-speed control piston is not installed in place. Install 2-speed control piston in proper location.
Orifice in oil passage of 2-speed control piston cham-
ber is clogged. Wash orifice before reassembly.
Plunger is installed backward. Check plunger for installing direction, and install it in a
proper direction.
3. Speed One cannot be engaged. Spring is not set in place. Install spring in proper position.
Spring is broken. Replace spring with new one. Then, remove foreign
articles thoroughly. Repair damaged parts, and reas-
semble the parts after cleanup. If deep scratches or
more than normal wear are found on the parts, the
parts should be replaced with new ones.
Plunger is installed backward. Check plunger for installing direction, and install it in a
proper direction.