. MAINTENANCE STANDARD TIGHTENING TORQUES FOR BOLTS AND NUTS STANDARD TIGHTENING TORQUES FOR BOLTS AND NUTS TORQUE LIST CAUTION Apply the following table for Hydraulic Hose. 4 - 12 If nuts, b olts, or othe r parts a re not tightened to th e specified torque, i t wil l cause looseness or dam age to the tightened part s, and this will cause failur e of the machine or problems with operation. Always p ay careful a ttention when tightening par Unless otherwise specifie d, tighten the metr ic nuts and bolts to t he torque shown in th e table below. If it is ne cessary to replac e any nut or bolt, always use a Komatsu genuine part of the sa me size as the part tha t was replaced.
Thread diameter of bolt (a)(mm) Width across flats (b)(mm) Tightening torque Target value Service limit Nm kgm lbft Nm kgm lbft 6 8 10 12 14 10 1 13 17 19 1 22 1 3.2 31 66 13 72 1.3 3.2 6.7 11. 17. 5 9.8 23.1 48.5 5 83.2 5 126.6 11.8-14.7 27-34 59-74 98-123 153-190 1.2-1.5 2.8-3.5 6.0-7.5 10.0-12.5 15.5-19.5 8.7-10.8 20.3-25.3 43.4-54.2 72.3-90.4 112.1-141 16 18 20 22 24 24 2 27 3 30 5 32 6 36 8 60 60 10 88 83 26. 37 52. 70. 90 5 191.7 267.6 3 378.3 3 508.5 651 235-285 320-400 455-565 610-765 785-980 23.5-29.5 33.0-41.0 46.5-58.0 62.5-78.0 80.0-100.0 170.0-213.4 238.7-296.6 336.3-419.5 452.1-564.2 578.6-723.3 27 30 33 36 39 41 1 46 1 50 2 55 2 60 3 295 720 210 750 280 132. 175. 225. 280.
335. 5 958.4 0 1265.8 0 1627.4 0 2025.2 0 2423.1 1150-1440 1520-1910 1960-2450 2450-3040 2890-3630 118.0-147.0 155.0-195.0 200.0-250.0 250.0-310.0 295.0-370.0 853.5-1063.3 1121.1-1410.4 1446.6-1808.3 1808.3-2242.2 2133.7-2676.2 Nominal - No.
of threads (a) Width across flats (b (mm) Tightening torque Target value Permissible range ) Nm kgm lbft Nm kgm lbft Permissible range gm lbft Nm kgm lbft 9/16 -18UNF 19 44 4.5 32.5 35 - 63 3.5 - 6.5 25.3 - 47.0 11/16 -16UN 22 74 7.5 54.2 54 - 93 5.5 - 9.5 39.8 - 68.7 13/16 -16UN 27 103 1 0.5 75.9 84 - 132 8.5 - 13.5 61.5 - 97.6 1 -14UNS 32 157 1 6.0 115.7 128 - 186 13.0 - 19.0 94.0 - 137.4 13/16 -12UN 36 216 2 2.0 159.1 177 - 245 18.0 - 25.0 130.2 - 180.8