Ford 2002 F650 Owner's Manual page 235

General Maintenance Information
Cam brakes - automatic slack adjusters
Inspect standard air brakes equipped with automatic slack adjusters for
proper brake adjustment every four months or 32 000 km (20 000 miles)
whichever occurs first.
However, more frequent inspection is required if your vehicle's brakes
are subjected to heavy use or adverse operating conditions such as:
• Frequent brake applications while fully loaded.
• Operation on hilly or mountainous terrain.
• Frequent operation on dirt, gravel or mud.
Some aftermarket brake linings also require more frequent inspections.
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