In the early years of automobiles, leverage and upper-body strength were required to crank the steering wheel when sitting at a stop. This meant that manufacturers had to make larger steering wheels to give drivers more leverage to compensate for lack of strength. As cars and engines became larger throughout the 1950s, 1960s and 1970s, a larger steering wheel simply became no longer an option. For this reason, manufacturers reached back to the early 1920s to an invention that used hydraulic power to turn the wheels. The 1999 F-250, as with most vehicles of its era, came standard with power steering. Replacing the power steering pump on a 1999 F-250 with a 7.3-liter requires some special tools and close attention to detail.
Look at the drive belt on the front of the engine and draw a diagram with paper and pen of the belt’s routing for correct installation later.
Connect a half-inch-drive ratchet to the square hole on the pulley end of the belt tensioner pulley assembly. Rotate the tensioner clockwise, if the F-250 has air conditioning, or counterclockwise, if it does not have air conditioning, to relieve the tension on the drive belt. Pull the drive belt off the power steering pulley only.
Trace the air cleaner outlet hose toward the engine until you find where two smaller hoses connect to the outlet hose. Label the two hoses with masking tape and a permanent marker, and pull the hoses from the outlet hose.
Press and hold the unlocking button on the intake air temperature sensor wiring harness and pull the harness from the IAT sensor.
Loosen the hose clamp on each end of the air cleaner outlet hose with a Phillips screwdriver, and pull the hose from the air cleaner box and engine. Set the air cleaner outlet hose in a secure area.
Slide a drain pan under the truck, directly under the power steering pump to catch fluid as it drains. Remove the power steering pump pulley, using a power steering pump pulley removal tool. The exact process varies, depending on the type of remover used, so refer to the tool’s instructions for specifics. Never use a generic jawed puller to remove the pulley, as it can break or bend the pulley.
Squeeze the ears on the clamp on the end of the power steering return hose — the hose on top of the power steering pump — with slip-joint pliers. Slide the clamp up the return hose about 3 inches. Pull the return hose off the power steering pump and allow all of the fluid to drain from it into the drain pan.
Loosen the power steering pressure line — the metal line — with a line wrench and pull the pressure line from the pump.
Remove the three power steering pump retaining bolts with a ratchet and socket, and pull the power steering pump from its bracket just enough to access the lower most hose: the power steering-to-oil cooler return hose.
Squeeze the ears on the power steering-to-oil cooler return hose’s clamp with slip-joint pliers, and slide the clip up the hose about 3 inches. Pull the hose from the pump with a slight twisting motion. Remove the power steering pump from the engine compartment.
Press the power-steering-to-oil-cooler return hose onto the lower-most input on the power steering pump. Slide the hose clamp to the end of the hose with slip-joint pliers to secure it. Set the new power steering pump on the bracket and hand-thread its retaining bolts. Tighten the power steering pump retaining bolts to 60 foot-pounds with a torque wrench and socket.
Line up the power steering pump pulley with the power steering pump’s input shaft. Press the power steering pump pulley onto the shaft as far as possible. Hand-tighten the power steering pump pulley installer into the threaded end of the power steering pump’s input shaft. Hold the end of the installer steady with a combination wrench and turn the driver part of the installer counterclockwise with another combination wrench until the pulley seats fully on the power steering pump’s input shaft. Unscrew the power steering pump pulley installer from the power steering pump shaft.
Hand-thread the pressure hose into the threaded receptacle near the middle of the power steering pump. Tighten the pressure hose with a line wrench. Press the return hose onto the uppermost input on the power steering pump, and slide the hose clamp to the end of the hose with slip-joint pliers to secure the hose in place.
Look at the serpentine belt and check that it is still routed in the same way as in your diagram, as you may have disturbed it while removing the pump. Reroute the belt as needed using your diagram as a reference, but skipping the power steering pump.
Rotate the belt tensioner clockwise if the F-250 has air conditioning or counterclockwise if it does not, using a half-inch-drive ratchet. Route the drive belt over the power steering pulley and allow the belt tensioner to rotate back toward the belt until it engages the belt and holds tension on it. Remove the ratchet.
Unscrew the cap from the power steering pump, and add Mercon transmission fluid to the reservoir until the level reaches the crosshatched area on the reservoir dipstick. Tighten the cap onto the reservoir.
Install the air cleaner outlet hose onto the input on the engine and the outlet on the air filter box. Tighten the air outlet hose clamps with a Phillips screwdriver. Plug the two smaller hoses into the air filter outlet hose, using your labels as a reference. Pull the labels off the hoses. Plug the IAT sensor wiring harness into the IAT sensor.
Open the under-hood fuse block and remove the injector driver module relay — the third relay from the right rear of the fuse block — by pulling upward with a slight wiggling motion. This prevents the truck from starting while you circulate the power steering fluid.
Raise the front of the truck off the ground with a floor jack and slide jack stands under the frame rails. Lower the F-250 onto the jack stands.
Crank the engine for 10 to 15 seconds as you turn the wheel left to right, from stop-to-stop. Never crank the engine for longer than 15 seconds. Allow the vehicle to set for 1 minute. Repeat this step two times.
Raise the truck off the jack stands with a floor jack and remove the jack stands. Lower the F-250 to the ground.
Open the reservoir and refill the power steering pump reservoir with Mercon ATF until it reaches the crosshatched area on the dipstick. Tighten the dipstick into the reservoir.
Unscrew the cap from the auxiliary power steering pump reservoir — located on the driver’s side of the firewall — and add Mercon ATF until the fluid level is between the “Min” and “Max” lines.
Press the injector driver module relay back into its receptacle in the under-hood fuse block and close the fuse block’s lid.
Take the old fluid in the drain pan to a local used automotive fluid recycling center. Some auto parts stores take used fluids free of charge.
