F 250 2WD Pickup V8-351 5.8L (1982)
Wheels: All Technical Service Bulletins
Brakes - Shudder While Braking
Article No. 83-7-19
SHUDDER DURING BRAKING - SEMI-FLOAT REAR AXLE
LIGHT TRUCKS 1981-83 F-250/350
A brake shudder condition may be caused by the wheels warping the brake drums as well as brake system causal factors. The following procedure will
assist in determining the probable cause and appropriate service actions.
Verify the condition by road test.
^
Make sure tires are warm to eliminate "cold flat spots".
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Drive vehicle on smooth road at varying speeds between 30 mph and 55 mph. Determine whether a vehicle shudder condition exists during this
evaluation.
^
If a shudder condition exists during vehicle operation without brake application, service should be handled per Section 18-01 of the Light Truck
Shop Manual. If shudder exists only during brake application, the following diagnostic procedure should be continued.
^
Apply brakes at varying brake pressure at speeds between 30 mph and 55 mph. Determine whether a shudder condition exists.
^
Using parking brake only, apply the parking brake at varying intensity between 30 mph and 55 mph. Determine whether a shudder condition
exists.
NOTE:
The parking brake release should be held in the "release" position to permit modulation of the parking brake pedal.
^
If the condition occurs during service brake application, but not during parking brake application, this condition is isolated to the front brake area.
^
If the condition occurs during both service brake and parking brake application, the condition is isolated to the rear brake area.
After verifying that a shudder condition exists during brake application, perform the following operations in sequence:
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Inspect tires for any obvious damage.
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Inspect wheel lug nuts for looseness. Correct torque is 85-115 ft.lbs. (nominal - 105 ft.lbs.) for the F-250 (under 8500 GVW) and 115-175 ft.lbs.
(nominal - 145 ft.lbs.) for the F-250 HD (over
8500 GVW) and F-350 (single rear). Torque wheel lug nuts to specification if necessary and retest vehicle. If condition is still evident, proceed to next
step.
^
Remove all wheel/tire assemblies and apply light coat of paint to the surface of each front rotor/rear drum that contacts the wheel, Re-install the
original tire/wheel assemblies and torque each wheel lug nut to 85 ft.lbs.
^
Remove tire/wheel assemblies and inspect for evidence of contact between wheel and front rotor/rear brake drum at all wheel lug locations. This is
done by observing the pattern on the paint applied above.
^
If the wheels make full contact with the rotor/rear brake drum at all lug locations, proceed to section "A" if the condition is isolated to the front
brakes or to section "B" if the condition is isolated to the rear brakes.
^
If the above procedure indicates wheel does not make contact at all lugs, locate another similar vehicle that does not exhibit this condition and
switch the tire/wheel assemblies between the two vehicles. Repeat the above paint procedure to the front rotors and rear brake drums. Check each
wheel to rotor/brake drum contact pattern at all lug locations.
^
Road test vehicle.
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If the shudder condition has been eliminated, the original vehicle wheels should be replaced with the following wheels which incorporate
improved uniformity discs.
NOTE:
Reinstall the tires from the original customer unit:
Original
Replacement
16 x 6K
16 x 6K: E3TZ-1015-S
16.5 x 6
16.5 x 6.75: D5TZ-1007-F
16.5 x 6.75
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If the wheels make full contact and the shudder condition has not been corrected by the above tire/wheel replacement, refer to Section A for the
front brakes and Section B for the rear brakes.
Section A
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Check front wheel bearing end play. If excessive, reset per Section 11-10 of the Truck Shop Manual, and retest the vehicle for shudder.
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If not excessive, or if the shudder still exists, remove the front brake calipers.
^
Sliding surfaces of caliper and spindle caliper support should be wire brushed to remove all scale, rust, and foreign material. A light uniform
coating of lubricant D7AZ-19590-A should be applied to both sliding surfaces.
^
Inspect brake linings and if excessively worn, replace.
