GMC T-Series 1999, Owner'S Manual

Page: 313 / 344

yellow blue
Scheduled Maintenance (DURAMAX
t
DIESEL)
7-51
Check fuel cap gasket for even filler neck imprint.
Replace parts as needed.
(35) = Drain, flush and refill cooling system. See
“Recommended Fluids and Lubricants” in the Index for
what to use. Inspect hoses. Clean radiator, condenser,
pressure cap and neck. Pressure test cooling system and
pressure cap.
(37) = Rear axle service: Change the lubricant. See
“Recommended Fluids and Lubricants” in the Index.
(38) = Front axle service: Re
-
pack upper kingpin
roller bearing.
(39) = Air brake service:
D Inspect brake lines and hoses for proper hook
-
up,
binding, leaks, cracks, chafing, etc. Inspect drum brake
linings for wear or cracks. Inspect other brake parts at
each wheel, including drums, wheel cylinders and
piston heat shields and boots. Check brake pedal for
excessive free play or travel (or every 6 months,
whichever occurs first) and have serviced if needed.
Check brakes more often if driving habits and
conditions result in frequent braking.
D Test air lines for leaks; tighten as needed. Replace
compressor filter.
D Inspect air parking brake chamber for leaks and
damage. Inspect lines and hoses for leaks, cracks,
chafing, etc. Also check all attachments for
tightness, wear or damage. Note: The spring brake
section of the rear brake diaphragms are
non
-
serviceable.
D Replace the air compressor filter element, mounted
on the air compressor. For remote air compressor
intake service, refer to air cleaner filter replacement.
(40) = Clean and lubricate air brake automatic slack
adjuster. Check pushrod travel and auto adjustment
operation. Have serviced if needed.
(41) = Air brake chamber service: Check operation,
mounting, clamps and air lines and check for leaks.
(42) = Trailer brake hand control valve service: Check
operation; lubricate cam and follower.