GMC 1993 Safari Owner's Manual page 320

Scheduled Maintenance Services
Parking brake and transmission P (Park) mechanism operation -
When you are doing this check, your vehicle could begin to move.
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You or others could be injured and property could be damaged.
Make sure there is room in front of your vehicle in case you begin
to roll. Be ready to apply the regular brake at once should the
vehicle begin to move.
Park on a fairly steep hill, with the vehicle facing downhill. Keeping your foot
on the regular brake, set the manual parking brake.
To check the parking brake: With the engine running and the
transmission in N (Neutral), slowly remove foot pressure from the regular
brake pedal. Do this until the vehicle is held by the parking brake only.
To check the P (Park) mechanism's holding ability: Apply the regular
brake and shift to P (Park). Release the manual parking brake, then
slowly release the regular brake.
Lap and shoulder belts condition and operation -Inspect belt system,
including: webbing, buckles, latch plates, retractors, guide loops and anchors.
Have a belt assembly replaced i f the webbing has been cut or otherwise
damaged.
Body Lubrication Service -Lubricate all body door hinges including the
tailgate, tailgate handle pivot points, and tailgate mounted spare tire carrier (if
equipped), lubricate the body hood, fuel door and rear compartment hinges,
latches, any locks and any moving seat hardware. Lubricate the hood safety
lever pivot and prop rod pivot. More frequent lubrication may be required
when exposed to a corrosive environment.
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