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MAINTENANCE
High-Strength Bolt Connections (continued)
Procedure for determination of the tightening torque for the
crawler carrier mounting bolts after the first 1000 operating
hours, see illustration Z25246
1. Loosen the two measuring bolts (7) at the left crawler carrier
and the two measuring bolts at the right crawler carrier.
Do not lubricate the measuring bolts.
2. Tighten the four measuring bolts (7) with 150 Nm.
3. Attach the measuring device (1 - 6).
4. Set the dial gauge (2) to the zero position.
5. Attach the special hydraulic torque wrench (1), see illustration
Z24072 on next page to the measuring bolt (7).
6. Increase the pressure at the hydraulic torque wrench until a
torque of 2100 Nm is reached and tighten the measuring bolt.
7. Record the pressure and the change of the bolt length in a
table.
8. Increase the pressure further by steps of 10 bar until the
required elongation of 0.93 mm of the measuring bolts (7) is
reached.
9. Record the corresponding hydraulic pressures in a table.
10. Repeat this procedure on all four measuring bolts (7).
11. Add the 4 determined hydraulic pressures and then divide by
4 to obtain an average value.
12. Now loosen only one of the mounting bolts (M48) and tighten
up to the determined average pressure.
DO NOT loosen more than one bolt at the same time.
DO NOT lubricate the bolts (M48).
13. Repeat this procedure step by step at all of the 156 mounting
bolts (M48) .
CAUTION
4.12 EVERY 1000 OPERATING HOURS OR EVERY 6 MONTH
451
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