Ford F-650 Owner's Manual page 185

Periodic checking of push rod travel or brake adjustment is essential for
effective braking. Check push rod travel every service interval to determine
if adjustment is correct. Brake chamber push rods on original equipment
chambers now incorporate an orange paint marker near the base of the
push rod as a stroke indicator to aid in adjustment checks. If the push rod
is clean and the brakes are out of adjustment, the orange marker can be
seen protruding from the chamber when the brakes are applied.
WARNING: Do not manually adjust the automatic slack
adjusters to correct excessive push rod stroke as it may result in
reduced brake effectiveness and a vehicle crash. Excessive push rod
stroke indicates that a problem exists with the automatic adjuster, with
the installation of the adjuster, or with foundation brake components
that manual adjustment does not remedy. Seek service from a qualified
facility for excessive push rod stroke.
Inspect the brake lining every maintenance interval. When brake lining or
blocks are worn to within 1/16 inch (1.6 mm) of rivets, replace the brake
linings. This inspection or adjustment should only be performed by a
qualified technician and must be in accordance with instructions
provided by the service manual.
Do not back off or disconnect the front brakes so that they are less
effective, letting the rear brakes do all the stopping of the vehicle. Do
not overlook the brakes on the trailer, either. Brake condition on the
trailer is just as important as the tractor. Proper brake balance on trucks
and tractor-trailers is essential for effective braking.
Once a year, the entire brake system must be inspected. Check the
following:
• Any rubber components for deterioration. These components should
be inspected by a qualified technician and replaced as necessary.
Replacement intervals vary according to the severity and length of
vehicle service.
• Condition of brake drums, brake chambers and slack adjusters.
• System for air leaks.
• Hose or pipes for rust, damage and deterioration.
• Operation of service and parking brakes.
Some parts such as air brake chamber diaphragm, air compressor and air
cleaner should be inspected periodically and replaced if considered
unserviceable.
2012 F-650/750 (f67)
Supplement, 2nd Printing
USA (fus)
Maintenance and Specifications
185