Chevrolet T-Series Owner's Manual page 271

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)
Thermostatically controlled engine cooling fan
service. (3) (17)
Shields and underhood insulation
service. (3) (4) (18)
22,500 Miles (36 000 km)
Check fluid levels (or every 3 months,
whichever occurs first). (1) (5)
Chassis lubrication service (or every 6 months,
whichever occurs first). (10)
Inspect door hinge pins and bushings and
replace as necessary.
Cooling system service. Clean the cooling
system filter cap with clean water, clean
the core, pressure test the cap and the system
for proper pressure capability, and inspect
the condition of cooling and heater hoses and
clamps. Replace hoses if cracked, swollen,
or damaged.
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)
Air brake system valve service (or every
3 months, or every 900 hours, whichever
occurs first). (31)
Air intake system service (or every 24 months,
whichever occurs first). (3) (4) (20)
Rear axle air shift motor service. (9)
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