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MAINTENANCE
TIGHTENING TORQUE SPECIFICATIONS
TIGHTENING TORQUE SPECIFICATIONS
TIGHTENING TORQUE LIST
CAUTION
If nuts, bolts, or other parts are not tightened to the specified torque, it will cause looseness or damage to the tightened parts, and
this will cause failure of the machine or problems with operation.
Always pay careful attention when tightening parts.
Unless otherwise specified, tighten the metric nuts and bolts to the torque shown in the table below.
If it is necessary to replace any nut or bolt, always use a Komatsu genuine part of the same size as the part that 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
13
17
19
22
13.2
31
66
113
172
1.35
3.2
6.7
11.5
17.5
9.8
23.1
48.5
83.2
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
27
30
32
36
260
360
510
688
883
26.5
37
52.3
70.3
90
191.7
267.6
378.3
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
46
50
55
60
1295
1720
2210
2750
3280
132.5
175.0
225.0
280.0
335.0
958.4
1265.8
1627.4
2025.2
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
Apply the following table for Hydraulic Hose.
Thread
diameter a
(mm)
Width
across
flat
b(mm)
Tightening torque [Nm (kgm)]
Target
value
Permissible range
9/16 -18UNF 19 44 (4.5) 35 - 54 (3.5 - 5.5)
11/16 -16UN 22 74 (7.5) 54 - 93 (5.5 - 9.5)
13/16 -16UN 27 103 (10.5) 84 - 132 (8.5 - 13.5)
1 -14UNS 32 157 (16.0) 128 - 186 (13.0 - 19.0)
1
·
3/16 -12UN 36 216 (22.0) 177 - 245 (18.0 - 25.0)
*1-7/16-12UN
-2B
41 215 (22) 176 - 234 (18 - 24)
The torques marked * indicate the tightening torques for the hoses at the top of the swivel joint.
4 - 12
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