JLG sky trak mmv Service Manual page 192

Boom
Boom Troubleshooting (Continued)
Problem
8. Rapid boom pad wear.
12. Fork Side Shift hydraulics will
not operate.
13. Excessive chain wear.
4.48
Cause
1. Incorrect wear pad gap.
2. Rapid cycle times with heavy
loads.
3. Contaminated, corroded or
rusted wear pad sliding
surfaces.
4. Operating in extremely dusty/
abrasive conditions.
1. Fork Side Shift hydraulic or
electrical system(s) not
operating properly.
1. Improper chain adjustment.
2. Chain sheave(s) not properly
lubricated.
3. Chain sheave(s) not rotating
freely.
4. Improper chain lubrication.
Remedy
1. Check wear pad gaps and
correct as needed. (Refer to
Section 4.3.7, a. Boom Wear
Pad Check .)
2. Reduce cycle times.
3. Remove contamination and/or
corrosion from wear pad sliding
surfaces and lubricate. (Refer to
Section 4.3.7, c. Boom Wear
Pad Lubrication .) If the surfaces
cannot be reconditioned,
replace the boom section(s).
4. Clean equipment frequently.
1. Refer to Section 9.8, Hydraulic
Circuits and Troubleshooting
and/or Section 10.7.21, Left
Fork - Side Shift Left, Circuit
and Troubleshooting and/or
Section 10.7.23, Right Fork -
Side Shift Left, Circuit and
Troubleshooting .
1. Adjust to correct tension. (Refer
to Section 4.3.6, b. Extend
Chain Adjustment .) Replace
chain(s) as needed. (Refer to
Section 4.3.6, c. Chain
Replacement .)
2. Lubricate chain sheave. (Refer
to Section 4.3.8, Boom
Lubrication Points .)
3. Lubricate chain sheave. (Refer
to Section 4.3.8, Boom
Lubrication Points .) Repair or
replace chain sheave(s) as
needed.
4. Lubricate at regular intervals
(refer to Owners/Operators
manual). Replace chain(s) as
needed (refer to Section 4.3.6,
c. Chain Replacement ).
Model MMV Rev. 12/04