Toro TRX-20 Operator's Manual page 39

Figure 60
1. Spoils auger
2. Bolts
3. Drive sprocket
4. Sprocket mounting surface
4. Loosen the 2 bolts and nuts securing the boom to the
trencher arm.
5. Loosen the jam nut on the adjusting bolt in the boom.
6. Loosen the adjusting bolt until you can remove the
chain from the boom.
7. Remove the chain from the drive sprocket.
8. Remove the six bolts securing the drive sprocket
(Figure 60).
9. Remove and discard the drive sprocket (Figure 60).
10. Clean the sprocket mounting surface on the trencher
(Figure 60).
11. Slide the new sprocket onto the shaft (Figure 60).
Important: The arrow on the sprocket face should
be visible from the right side of the trench and
should point in a clockwise direction; if not, turn
the sprocket around.
12. Thread the six bolts into the sprocket finger tight
(Figure 60).
13. Slowly begin tightening the bolts progressing around
the sprocket until all bolts are torqued to 129 to 155
N-m (95 to 115 ft-lb).
Important: Tighten each bolt only half way first,
working your way around the six bolts, then return
to each bolt in turn and torque them
14. Loop the chain over the auger drive shaft and onto the
drive sprocket, ensuring that the teeth point forward
on the upper span.
15. Set the upper span of the chain into place on the
trencher boom, then wrap the chain around the roller
at the end of the boom.
16. Thread the adjustment bolt into the boom and turn it
in until there is 3.8 to 6.3 cm (1-1/2 to 2-1/2 inches) of
slack in the chain on the bottom span.
17. Thread the jam nut down the adjusting bolt and tighten
it securely against the boom.
18. Torque the 2 bolts and nuts securing the boom to 183
to 223 N-m (135 to 165 ft-lb).
19. Install the spoils auger using the bolt and nut you
removed previously. Torque the bolt and nut to 102
N-m (75 ft-lb).
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