GMC 2010 T-Series Owner's Manual page 260

Replace the air compressor filter element, mounted
on the cab rear bridge. For remote air compressor
intake service, refer to engine air cleaner filter
replacement.
Remove, disassemble, clean, and inspect the
safety valve, service brake chambers, quick
release valve, quick release/double check valve
combination, parking brake control valve, double
check valve, pressure protection valve, and ether
injector.
Remove, disassemble, and clean the application
valve; replace parts showing wear.
Remove, disassemble, clean, and inspect the
spring brake control valve; replace rubber parts.
(27) = Clean and lubricate air brake automatic slack
adjuster. Check pushrod travel and auto adjustment
operation. Have serviced if needed.
(28) = Air brake chamber service: Check operation,
mounting clamps, and air lines and check for leaks.
(29) = Trailer brake hand control valve service: Check
operation; lubricate cam and follower.
6-22
(30) = Tighten the wheel stud nuts to the specified
torque values at 160 km (100 miles). Thereafter, tighten
them 1 600 km (1,000 miles) after each time the wheel is
removed. See Tightening the Wheel Nuts on page 5 63.
(31) = Inspect and clean any accumulated dirt, gravel,
or other foreign objects from the valves and valve boots
as needed. Using light oil, lubricate brake pedal to
brake application valve linkage components. Check any
rubber boots for cracks, holes, or deterioration and
replace if necessary.
(32) = Check for filter ash, sensor adjustment, and
sensor hose restriction. Clean as needed. This service
can be complex; you should have your dealer/retailer
perform this service.
(33) = If the vehicle is used primarily for long trip,
highway service, change the engine oil and filter every
28 800 km (18,000 miles), or every 12 months, or every
750 hours of engine operation, whichever occurs first.
(34) = Make sure any safety belt reminder light and
safety belt assemblies are working properly. Look for
any other loose or damaged safety belt system parts.
If you see anything that might keep a safety belt system
from doing its job, have it repaired. Have any torn or
frayed safety belts replaced.