Komatsu HD785-5, Operation & Maintenance Manual

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MAINTENANCE
SERVICE PROCEDURE
CHECK WEAR OF REAR BRAKE DISC
WARNING
Carry out this check when the brake oil temperature is below 60
°
C (140
°
F).
When carrying out the work with two workers, if the retarder control lever is pulled suddenly, there is danger that the rod of the
disc wear measurement gauge may fly out suddenly under hydraulic pressure. Pull the rod out fully, and operate the retarder
control lever slowly over a period of approx. 10 seconds.
If the disc wear approaches the wear limit, check the condition frequently, regardless of the maintenance interval. In addition,
check the retarder capacity carefully.
1. Stop the machine on level ground, set the parking brake valve lever to the PARKING position, then check that
the other brakes are not applied before starting inspection.
2. Remove plug (1) from the rear brake and install the disc wear
measurement gauge.
When doing this, tighten the nipple fully and pull the rod of the
disc wear measurement gauge out fully. If it is not pulled out,
there is danger that the rod may fly out under hydraulic
pressure when the retarder lever is pulled.
Part number for gauge: 561-98-61122
3. Turn the starting switch to the ON position and check that the
air pressure gauge is in the green range.
4. If the air pressure is low, start the engine and run the engine at
2,000 rpm until the air pressure gauge enters the green range.
When it enters the green range, turn the starting switch OFF.
5. Operate the retarder control lever slowly over approx. 10 seconds to apply the brake.
In this condition, push the gauge rod in slowly until it contacts the piston.
6. If mark (A) of the disc wear measurement gauge goes in
beyond the end face of the case, this means that the disc has
reached the wear limit.
If this happens, please contact your Komatsu distributor for
inspection and maintenance.
If the rod is released suddenly after measurement, there is
great danger that the rod may fly out under hydraulic pressure.
Keep the rod held down and let it back slowly. When it reaches
the end of its stroke, release it.
7. Return the retarder control lever.
8. Remove the disc wear measurement gauge and install plug (1).
9. Bleed all the air from the circuit. For details, see "BLEED AIR FROM REAR BRAKE (PAGE 4-28)".
CHECK TIGHTENING PARTS OF TURBOCHARGER
Contact your Komatsu distributor to have the tightening portions checked.
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