Front brakes locked up 1964 Ford Fairlane

what would cause the front brakes to lock up

Being a 1964 I think it came with drum brakes on the front. Some of them where modified with and changed over to disc brakes. That being said it is difficult to tell without looking at it. The first thing would be to remove the wheels and examine the assembly.

Number one cause on a vehicle that old would be RUST in my opinion. 2nd would be part of the internal drum hardware has broken an lodged inside.

Front Drum Brakes

Drum brakes on all Fairlanes and Torinos employ single-anchor, internal-expanding, and self-adjusting brake assemblies. The automatic adjuster continuously maintains correct operating clearance between the linings and the drums by adjusting the brake in small increments in direct proportion to lining wear. When applying the brakes while backing up, the linings tend to follow the rotating drum counterclockwise, thus forcing the upper end of the primary shoe against the anchor pin. Simultaneously, the wheel cylinder pushes the upper end of the secondary shoe and cable guide outward, away from the anchor pin. This movement of the secondary shoe causes the cable to pull the adjusting lever upward and against the end of the tooth on the adjusting screw star wheel. As lining wear increases, the upward travel of the adjusting lever also increases. When the linings have worn sufficiently to allow the lever to move upward far enough, it passes over the end of the tooth and engages it. Upon release of the brakes, the adjusting spring pulls the adjuster lever downward, turning the star wheel and expanding the brakes.

Inspection

Raise the front of the car and support the car with safety stands. Make sure the parking brake is not on.
Remove the lug nuts that attach the wheels to the axle shaft and remove the tires and wheels from the car. Using a pair of pliers, remove the Tinnerman nuts from the wheel studs. Pull the brake drum off axle shaft. If the brakes are adjusted too tightly to remove the drum, see step four. If you can remove the drum, see step five.Self-adjusting drum brake assemblies

The front tire, wheel and brake drum can be removed as an assembly. Remove the hub cap, then either pry the dust cover off the spindle with a screwdriver or pull it off with a pair of channel-lock pliers. Remove the cotter pin from the spindle. Slide the nut lock off the adjusting nut, then loosen the adjusting nut until it reaches the end of the spindle. Do not remove the adjusting nut yet. Grab the tire and pull it out toward yourself, then push it back into position. This will free the outer wheel bearing from the drum hub. If the brakes are adjusted up too tightly to allow the drum to be pulled off them, go to step four and loosen up the brakes, then return here. Remove the adjusting nut, washer and outer bearing from the spindle. Pull the tire, wheel, and brake drum off the spindle.
If the brakes are too tight to remove the drum, get under the car (make sure you have safety stands under the car to support it) and remove the rubber plug from the bottom of the brake backing plate. Shine a flashlight into the slot in the plate. You will see the top of the adjusting screw star wheel and the adjusting lever for the automatic brake adjusting mechanism. To back off on the adjusting screw, you must first insert a small, thin screwdriver or a piece of firm wire (coat-hanger wire) into the adjusting slot and push the adjusting lever away from the adjusting screw. Then, insert a brake adjusting spoon into the slot and engage the top of the star wheel. Lift up on the bottom of the adjusting spoon to force the adjusting screw star wheel downward. Repeat this operation until the brake drum is free of the brake shoes and can be pulled off.
Clean the brake shoes and the inside of the brake drum. There must be at least ¹/₁₆ in. of brake lining above the heads of the brake shoe attaching rivets. The lining should not be cracked or contaminated with grease or brake fluid. If there is grease or brake fluid on the lining, it must be replaced and the source of the leak must be found and corrected. Brake fluid on the lining means leaking wheel cylinders. Grease on the brake lining means a leaking grease retainer. If the lining is slightly glazed but otherwise in good condition, it can be cleaned up with medium sandpaper. Lift up the bottom of the wheel cylinder boots and inspect the ends of the wheel cylinders. A small amount of fluid in the end of the cylinders should be considered normal. If fluid runs out of the cylinder when the boots are lifted, however, the wheel cylinder must be rebuilt or replaced. Examine the inside of the brake drum; it should have a smooth, dull finish. If excessive brake shoe wear caused grooves to wear in the drum it must be machined or replaced. If the inside of the drum is slightly glazed, but otherwise good, it can be cleaned up with medium sandpaper.
If no repairs are required, install the drum and wheel. If the brake adjustment was changed to remove the drum, adjust the brakes until the drum will just fit over the brakes. After the wheel is installed it will be necessary to complete the adjustment.Tighten the wheel bearing adjusting nut to 17–25 ft. lbs. while rotating the wheel. This will seat the bearing. Loosen the adjusting nut ¹/₂ turn, then retighten it to 10–15 in. lbs.

Adjustments

Raise the car and support it with safety stands.
Remove the rubber plug from the adjusting slot on the backing plate.
Insert a brake adjusting spoon into the slot and engage the lowest possible tooth on the star wheel. Move the end of the brake spoon downward to move the star wheel upward and expand the adjusting screw. Repeat this operation until the brakes lock the wheel.
Insert a small screwdriver or piece of firm wire (coat-hanger wire) into the adjusting slot and push the automatic adjuster lever out and free of the star wheel on the adjusting screw.
Holding the adjusting lever out of the way, engage the topmost tooth possible on the star wheel with a brake adjusting spoon. Move the end of the adjusting spoon upward to move the adjusting screw star wheel downward and contract the adjusting screw. Back off the adjusting screw star wheel until the wheel spins freely with a minimum of drag. Keep track of the number of turns the star wheel is backed off.
Repeat this operation for the other side. When backing off the brakes on the other side, the adjusting lever must be backed off the same number of turns to prevent side-to-side brake pull.
Repeat this operation on the other set of brakes.
When all four brakes are adjusted, make several stops, while backing the car, to equalize all of the wheels.
Road-test the car.