GMC T-Series 2007 Owner's Manual page 299

❑ Parking brake service (or every 6 months,
whichever occurs first). (7)
❑ Air brake service (or every 6 months, whichever
occurs first). (26)
❑ Air brake automatic slack adjuster service
(or every 500 hours, whichever occurs first). (27)
❑ Check air brake relay valve operation and check
for leaks (or every month, or every 300 hours,
whichever occurs first).
❑ Clean air brake application valve (or every
3 months, or every 300 hours, whichever
occurs first). Lubricate linkage.
❑ Air brake chamber service (or every 2 months,
whichever occurs first). (28)
❑ Air compressor dry element pleated paper air
strainer service (or every 2 months, or every
800 hours, whichever occurs first).
❑ Thermostatically controlled engine cooling fan
service. (3) (17)
❑ Shields and underhood insulation
service. (3) (4) (18)
37,500 Miles (60 000 km)
❑ Check fluid levels (or every 3 months,
whichever occurs first). (1) (5)
❑ Chassis lubrication service (or every 6 months,
whichever occurs first). (10)
❑ Wheels and tires service. (13)
❑ Hydraulic brake service (or every 6 months,
whichever occurs first). (6) (30)
❑ Parking brake service (or every 6 months,
whichever occurs first). (7)
❑ Air brake service (or every 6 months, whichever
occurs first). (26)
❑ Air brake automatic slack adjuster service
(or every 500 hours, whichever occurs first). (27)
❑ Check air brake relay valve operation and check
for leaks (or every month, or every 300 hours,
whichever occurs first).
❑ Clean air brake application valve (or every
3 months, or every 300 hours, whichever
occurs first). Lubricate linkage.
❑ Air brake chamber service (or every 2 months,
whichever occurs first). (28)
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