GMC T-Series 1999, Owner'S Manual, Page: 288 / 344

Scheduled Maintenance (Except DURAMAX
t
DIESEL)
yellow blue
7-26
(31) = Check EGR system as described in the service
manual. See “Service and Owner Publications” in
the Index.
(32) = Inspect Electronic Vacuum Regulator Valve
(EVRV) filter for excessive contamination or plugging.
If needed, clean filter with solution of soap and water,
let dry and install.
(33) = Check the PCV system for proper operation and
clean PCV valve. Replace hoses as needed.
(34) = Replace PCV valve and blow out the PCV valve
hose with compressed air. Replace hoses 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. For Caterpillar
R
diesel engines, always
refer to the Caterpillar Diesel Engine Operation &
Maintenance Manual for coolant recommendations and
change intervals.
(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.