Komatsu PC88MR-10 Shop Manual page 377

3. Apply the wrench U5 to portion (C) (width across
flats: 12.7 mm) of tensioner assembly (2), and
turn it in the direction opposite to the tightening
direction to decrease the tension of fan belt (4).
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 is loosely inserted, the wrench U5
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.
4. 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.
5. Replace fan belt (4).
Check each pulley for breakage and crack.
PC88MR-10
fan belt (4), return
30 Testing and adjusting
6. After replacement, remove holding bracket U3 in
reverse order of installation.
Slowly and carefully return tensioner
assembly (2).
Engine and cooling system
30-27