Boom Chain Adjustment
For proper operation and boom life the extend and retract chains must be adjusted
properly. To adjust these chains use the following procedure.
THIRD SECTION EXTEND AND RETRACT CHAINS (4 SECTION BOOMS):
1. Fully retract the boom.
2. Measure the gap (4) between the front of second section and the back of the
third section. This gap should be .25 inch to .38 inch.
3. If adjustment is required, extend the boom approximately 1/2 way.
NOTE: Before attempting to turn one of the adjusting nuts, extend or retract
the boom slightly to relieve the tension on that nut. After extending the boom,
adjustment 1 will be under tension and 2 will be free. After retracting the boom,
adjustment 2 will be under tension and 1 will be free.
4. If the gap is less than .25 inch, loosen adjustment 2 and tighten adjustment 1
until the gap is within specifications.
5. If the gap is more than .38 inch, loosen adjustment 1 and tighten adjustment 2
until the gap is within specifications.
6. Fully retract the boom and recheck the gap. Repeat step 3 through 5 if necessary.
7. Fully extend the boom horizontal.
8. Through the first hole in the side plate of the second boom section (the hole
closer to the base section), measure the sag (3) of the retract chain. This
measurement must be taken from the bottom of the second section to the
bottom of the chain. This dimension should be 2.25 inches to 2.50 inches.
9. If the dimension is greater than 2.50 inches, loosen adjustments 1and 2 equal
amounts until the measurement is within specifications.
10. If the dimension is less than 2.25 inches, tighten adjustments 1and 2 equal
amounts until the measurement is within specifications.
259REVISED: