F 350 4WD Pickup V8-7.3L DSL (1988)
NOTE:
VEHICLES BUILT AFTER MAY 1990 ARE EQUIPPED WITH GREASABLE STEEL SOCKET STEERING LINKAGE.
Diagnostic Procedure # 6 - Brake Imbalance
DIAGNOSTIC PROCEDURE # 6 - BRAKE IMBALANCE
1.
Spin the front tires to make sure the front hubs are unlocked. If the hubs are unlocked, the axle shaft will not rotate with the wheels (4X4 models
only).
2.
Check for front wheel rotational drag with warm/hot brakes.
a.
Make a series of 10 stops from speeds of 30 mph (48 km/h).
b.
Make the 10 stops with no more than 30 second intervals between stops. This generally will induce a maximum pull if there is a drift/pull
concern.
c.
Raise the front end of the truck so that both tires are off the ground.
d.
Rotate the front wheels by hand.
NOTE:
FOR ALL 4 WHEEL DRIVE TRUCKS, MAKE SURE THE HUBS ARE DISENGAGED.
Both tires should rotate about the same amount, with little brake drag occuring. Some brake drag will naturally be present for each size of truck.
3.
If the truck has excess brake drag, proceed as follows:
a.
Open the bleed screw on the affected wheel to check for residual pressure in the brake lines. If there is a squirt of brake fluid out the bleeder
screw and the drag is reduced or eliminated, the master cylinder may not be allowing the brake fluid to return to the reservoir.
b.
Check the master cylinder push rod adjustment. Refer to the appropriate Truck Shop Manual, Section 12-30 for service details.
c.
Check the brake pedal to determine if it is fully returning.
4.
Remove both calipers and check piston retraction using a "C" clamp and wooden block. The piston should easily move back into the bore under
the force of the clamp. Re-build or replace as needed.
5.
If Steps 1 through 4 have not determined the concern, swap rotors and linings from side to side.
