Komatsu PC88MR-10 Shop Manual page 379

Make sure that it is securely inserted into
part (C) of tensioner assembly (2) before
turning the wrench U5. (The spring of
tensioner assembly (2) is strong. If the
wrench U5 is loosely inserted, the wrench
may accidentally come off while being
turned, and it is extremely dangerous.)
After removing
tensioner assembly (2) to its original
position slowly and carefully.
Be careful not to get your fingers caught
between the pulley and fan belt (4) during
work.
7. Tighten nut U4 at the position where the belt
tension was reduced.
a Check that holding bracket U3 is inserted
between protrusions (b) and (d) of auto
tensioner (2), and that the end surface of
collar U2 and that of nut U4 become flush at
this time.
If holding bracket U3 is insufficiently
clipped between protrusions (b) and (d), it
may be removed. Therefore, securely
tighten nut U4.
8. Replace fan belt (4).
9. Apply a wrench to portion (c) (width across flats:
12.7 mm) of auto tensioner (2), and rotate it to
the opposite to the winding-up direction.
Be sure that wrench is set securely to
portion (c) of auto tensioner assembly (2)
before rotating it. (Since the spring force
of auto tensioner assembly (2) is strong,
the wrench might come off and induce
personal injury if it is rotated when not
securely attached.)
10.Remove nut U4 , and disconnect holding
bracket U3.
11.Remove collar U2.
12.Check that the arm stop part (c) of the auto-
tensioner (4) does contact with the spring case
stop part (e).
a Replace the auto-tensioner (2) if it does not.
PC88MR-10
fan belt (4), return
30 Testing and adjusting
13.Check that the arm (a) of the auto-tensioner (2)
is not moved by hand.
a Replace the auto-tensioner (2) if the arm (a)
is moved by hand.
14.Check that the arm stop part (c) contacts with
the spring case stop part (d) by using the wrench
U5.
a If the arm stop part (c) does not contact with
the spring case stop part (d), replace the
auto-tensioner (2).
a The auto-tensioner (2) is not needed to be
replaced if there is no abnormality in steps
12, 13, and 14.
Replace
(PC88MR-AT50-923-K-00-A)
1. Remove the bolt (5), and remove the auto-
tensioner (2).
2. Set the dowel pin (6) of the new auto-tensioner
(2) to be aligned with the groove (7) of the
cylinder block.
Engine and cooling system
30-29