Parking Brake Burnish Procedure; Air Suspension - GMC T-Series 2007 Owner's Manual

Parking Brake Burnish Procedure

All vehicles which have hydraulic brakes will have a
parking brake. It is recommended that the parking
brake be burnished as part of the new vehicle
break-in. The parking brake will work best after it
has been burnished following these instructions:
1. Making sure that there is no other traffic
around, get the vehicle speed up to 20 mph
(32 km/h) and pull up to apply the parking
brake. Let the vehicle come to a complete stop.
Apply the base brakes and disengage the
parking brake.
2. Repeat the burnishing procedure in Step 1 a
total of 10 times
3. Between stops, drive the vehicle about
2 1 ⁄ miles (4 km)
2
Notice: Driving with the parking brake on can
damage the transmission and brake system
parts. Verify that the parking brake is fully
released and the brake warning light is
off before driving.

Air Suspension

Your vehicle may have the Hendrickson
HAS Series single-axle air suspension which
is designed for a single-axle on-highway use.
This feature is available in 19,000 lb (8 613.3 kg),
21,000 lb (9 525.4 kg) and 23,000 lb (10 432.6 kg)
capacities.
Rear Air Suspension Dump Control
If your vehicle is equipped with the Hendrickson
HAS Series single-axle air suspension, you
may have this control. The air suspension dump
control allows the operator to lower the deck height
approximately 4.5 inches (11.5 cm) from the
normal frame height.
The switch to deflate
and inflate the air
suspension is located
on the instrument panel.
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