Repair And Fix it

The Ford F-Series is a family of full-size pickup trucks in continuous production since 1948. The F150 pickup has a rated carrying capacity of 3/4 ton, although modern versions of this truck can carry much more than that. The braking system on late-model F150s includes an anti-lock braking system, or ABS, as standard equipment. This feature allows a vehicle to stop during an emergency without locking the wheels. The brake controller on an F150 is also known as the hydraulic control unit, or HCU.

Instructions

1

Remove the negative cable from the battery with a socket wrench to ensure the engine doesnt start during the procedure. Disconnect the air cleaner assembly.

2

Disconnect the four fittings that connect the brake lines to the HCU with a socket wrench, and detach the brake lines from the HCU. Remove the three bolts that attach the HCU bracket to the vehicle frame, and disconnect the HCU bracket.

3

Remove the two nuts that attach the HCU to its bracket with a socket wrench, and disconnect the HCU from its bracket. Detach the ABS module from the HCU.

4

Attach the ABS module to the new HCU. Install the HCU to its bracket, and tighten its retaining nuts to 80 inch-pounds with a torque wrench. Connect the HCU bracket to the vehicle frame, and tighten the mounting bolts to 18 foot-pounds. Attach the brake lines to the HCU, and tighten the fittings to 13 foot-pounds.

5

Connect diagnostic tool Worldwide Diagnostic System 418-F224 to the vehicles data link connector. Bleed the ABS, and use the diagnostic tool to clear any ABS faults. A qualified mechanic typically performs this step.

A faulty brake magnet can severely impact the stopping power of a trailer. While some magnet problems will be apparent upon visual inspection, there may also be electrical problems that can impact performance. A compromised brake magnet can lead to weak or surging brakes, or cause the brakes to pull to one side. It is important to inspect and test the magnets each time the brakes are worked on to ensure maximum effectiveness.

Instructions

1

Jack the trailer up high enough that each wheel turns freely. Secure the trailer with blocks under the frame at each end and on both sides to reduce the danger of the trailer falling on you should the jacks fail.

2

Remove the lug nuts and pull the tires and rims off of each axle.

3

Take off the grease cap and remove the cotter pin and castle nut. If there is a spindle washer, remove this too. Gently remove the outer bearing, drum, seal and inner bearing.

4

Locate the brake magnet. Take a straight edge tool and lay it across the top of the magnet. The edge of the magnet should be parallel to the straight edge all the way across. Any pitting or changes in the magnets surface indicate abnormal wear and the magnet should be replaced.

5

Check the center of the magnet for copper coil. If any coil can be seen, the magnet is worn out and should be replaced.

6

Visually inspect the magnet for grease or oil residue. If any is found, replace the magnet.

7

Check the magnet for short circuits. Disconnect the leads and the strain relief so that you can pull the leads through the backing plate. Unclip the leads from the lever arm and disconnect the magnet. Connect the positive battery terminal to one end of the ammeter lead and the other end to one of the magnet wires. Use a piece of 16-gauge wire and connect the magnet housing to the negative battery terminal. The ammeter should not show a current reading. If it does, a short exists and the magnet should be replaced.

8

Keeping the magnet wire connected to the ammeter lead, take the other magnet wire and attach it to the negative battery terminal. Take the other ammeter lead and attach it to the positive terminal. An amp reading of 3.2 or more at 12 volts means there is a short circuit in the coil and the magnet should be replaced.

9

Check the brake lining, shoes and repack the bearings if needed while the wheel assembly is apart. Put the parts back on the axle in the opposite order of how you removed them.

Hydraulic motors utilize fluid pressure in the operation of the mechanical loads. (See Reference 1) Hydraulic motors are unable to function separately from a circuit, pump, valves, filters, hoses, metal tubing and other hydraulic components. There are three major types of hydraulic motors that each operate within this same capacity but are unique in their own respects.

Gear motors

Gear motors come in two types, internal and external. Internal gear motors generally are constructed of an output shaft and an inner-outer gear set. (See Reference 2) The outer gear has an additional tooth compared to the inner gear, and the shape of these teeth makes it so the two gears are constantly in contact with one another. Motor housings for the motors have kidney-shaped inlet and outlet ports. In addition, the center rotations of both gears are separated by a predetermined amount called the eccentricity. In this design, the center of the output shaft and the inner gear are located in the same place. (see Reference 2) In contrast to the internal design, external gear motors are constructed of matched gears contained within a single housing. A similar tooth formation is seen in both gears and propelled by fluid pressure, with one gear connected to an output shaft and the other an idler. The force of the pressure fluid creates the rotation of the gears along the outside of the housing, and the fluid flows at a low pressure from the other side of the motor. (See Reference 2)

Vane motors

Vane motors are constructed of a slotted rotor affixed to the drive shaft, which is then operated through the rotor. (See Reference 2) The vanes move in a radial direction to seal the cam ring. This ring, with dual major and minor sections, is connected by transitional ramps or sections. Grooves and holes in the vanes are used to provide balance to the radial forces throughout the operation of the motor. (See Reference 2)

Piston

There are two types of piston motors, axial and radial piston motors. With the axial piston motor, the cylinders are in a 360-degree circle and are parallel to one another. (See Reference 1) Each individual cylinder contains a piston that "reciprocates with one end of the piston pushing against an eccentric swash-plate located at one end of the bank of cylinders." (See Reference 1) Through this arrangement of cylinders, the plate is connected to an output shaft that is "axially aligned with the cylinders." (See Reference 1) Generally seen in cylindrical hydraulic motors, axial piston motors are largely meant for compact designs. Radial piston motors are defined by the arrangement of the pistons on cams alongside the camshaft that is then attached to the output shaft. Using a reciprocal movement, the pistons create a rotary motion to the variant shafts to create power. Radial piston hydraulic motors are often seen in vehicle and airplane engines but are additionally useful in large equipment such as forklifts.

Oil pressure in an engine is critical to proper operation and to avoiding irreparable damage to internal engine parts. Electric oil pressure gauges sense the oil pressure inside the engine, then transmit the pressure information to the gauge inside the vehicle. A malfunctioning oil pressure sensor may send erroneous information to the gauge. Test the sensor before you replace the gauge. The sensor screws into the engine block, which connects to the gauge by a wire that is routed through the firewall to the gauge on the dashboard.

Instructions

1

Find the oil pressure specification for your model vehicle and engine size in your owners manual or a vehicle service manual for your car. Find the voltage and resistance parameters for the oil pressure sensing unit in your vehicles service manual.

2

Disconnect the wires that attach to the oil pressure sensing unit. Its usually located on the bottom of the engine near the oil filter. Attach the multimeter that leads to the sensor and then start the vehicle. Check the multimeter and note the voltage and resistance reported by the multimeter.

3

Turn off the vehicle and disconnect the multimeter. Connect the potentiometer to the oil pressure sensing unit by connecting one lead to the blue and white wire on the sensor and the other potentiometer connection to the ground connection on the frame.

4

Set the potentiometer to the resistance (in ohms) as specified by your owners or service manual. Start the vehicle. Check the reading on the potentiometer and note the resistance. Turn off the vehicle, disconnect the potentiometer and reconnect the leads to the oil pressure sensor.

5

Replace an oil pressure sending unit that returns values outside the acceptable range for your model vehicle. Replace the electronic oil pressure gauge if the sending unit tested within acceptable ranges.