Replacing Fuel Pump In '99 Ford Mustang: Step-By-Step Guide

Replacing the fuel pump on a 1999 Ford Mustang is a complex process that requires a range of tools and safety precautions. The procedure involves jacking up the car, disconnecting the battery, and removing the fuel tank. It is important to clean the top of the pump assembly and to be cautious when removing the old pump to avoid knocking gunk into the tank. The replacement pump assembly can then be installed, followed by reconnecting the fuel lines and electrical connections. While the process is challenging, online forums and video tutorials provide detailed instructions and tips for a successful fuel pump replacement in a 99 Ford Mustang.

Disconnect the negative battery cable

Disconnecting the negative battery cable is an important first step when replacing the fuel pump on a 1999 Ford Mustang. This is because it ensures that there is no power flowing to the vehicle's electrical systems during the repair process, which is essential for safety.

To disconnect the negative battery cable, you will need to locate the battery in the engine bay. The negative cable is usually black and smaller than the red, positive cable. Once you have identified the negative cable, you will need to unhook it from the negative terminal on the battery. This can be done by loosening the clamp that holds the cable in place, usually with a wrench or socket. Be sure to wear protective gloves and eyewear during this process, as battery acid can be dangerous.

It is generally recommended to disconnect the negative cable before the positive cable to prevent any accidental shorts. Additionally, when replacing the battery cable, it is important to ensure that the new cable is the correct length and extends to the battery post without any extensions. This will ensure a proper connection and help prevent corrosion.

After completing the fuel pump replacement, you can reconnect the negative battery cable by simply attaching it to the negative terminal and tightening the clamp. Once the cable is secure, you can turn the key to the "On" position to check that the pump is working correctly.

Remove the filler neck

To remove the filler neck of a 99 Ford Mustang, you will need a long 3/8 drive extension, a new fuel filler neck gasket/seal (which should look like a rubber doughnut and costs $30 at the dealership), and some motor oil.

First, jack up your car as high as you can and put it on jack stands. Disconnect the negative battery cable. Open the fuel filler door and remove the three screws/bolts that hold the filler neck into the door. Pop the trunk and take off the right-side trunk cover. You'll then be able to see the filler neck. Once the three bolts are removed from behind the fuel door, grab a 1/2 inch socket and a few extensions, and crawl under the car. Loosen the driver's side strap at the front of the car. For the passenger side, there is a bolt at the front and the back. Loosen the back bolt first, and then the front. Now your tank is ready to be lowered.

At this point, you will need a partner. Lower the jack slowly while the other person guides the tank down. The tank will drop almost all the way. The filler neck goes into the side of the tank. Lower the tank quite a bit, then push the tank and pull the filler neck out of the tank (if you have over a 1/2 tank of gas, some will spill out). Once you pop the filler neck out of the tank, you can lower the tank all the way to the ground.

Prepare to drop the tank

To prepare to drop the tank of your 99 Ford Mustang, start by making sure the tank is empty, as this makes the tank much lighter. Jack up the car as high as you can and put it on jack stands. Disconnect the negative battery cable.

Open the fuel filler door and remove the bolts that hold the filler neck into the door. Pop the trunk and take off the right side trunk cover. You'll then be able to see the filler neck. Loosen the straps at the front of the car, on both the driver and passenger sides. You can then jack up the tank to take the weight off the straps and remove the bolts.

Now you are ready to drop the tank. This is easier with a partner. Slowly lower the jack while the other person guides the tank down. It will drop almost all the way. The filler neck goes into the side of the tank, so you will need to drop the tank quite a bit, then push the tank and pull the filler neck out. If the tank is more than half full, some fuel will spill out.

Once you pop the filler neck out, you can lower the tank all the way to the ground. The fuel lines on top have plenty of room to get it lowered. Set the tank on the ground and unhook one electrical connection by the rear bumper. Now, the tank is ready to be slid out from under the car.

Clean the pump assembly

To clean the pump assembly of your 1999 Ford Mustang, you will need to first remove the fuel pump. This will involve jacking up your car, disconnecting the negative battery cable, and removing bolts and straps. Once the fuel tank is lowered, you can disconnect the fuel lines and electrical connections.

Now, to clean the pump assembly:

Take a screwdriver and a shop-vac, and clean the top of the pump assembly thoroughly. It is important to remove any dirt, debris, or residue to prevent it from falling into the fuel tank. Use a hammer to gently tap the lock ring on top counter-clockwise until it pops loose. You can apply some WD40 to make this process easier. Once the lock ring is off, carefully slide out the pump assembly. Be cautious not to knock any debris or gunk into the tank.

Inspect the assembly and clean it with appropriate tools and solutions. Ensure that all dirt, residue, and gunk are removed. You can use a brush or a soft cloth to wipe down the assembly, removing any remaining residue. Rinse the assembly with a suitable cleaning solution if necessary. Ensure that the assembly is completely dry before reinstallation.

After cleaning, carefully slide the pump assembly back into the fuel tank. Reinstall the lock ring and ensure it is securely tightened. Reattach the fuel lines and electrical connections. Finally, reconnect the negative battery cable and turn the key to the "On" position to check if the pump is working correctly.

Refer to the Mustang service manual or seek professional guidance if you are unsure about any steps or procedures.

Reinstall the new pump

To reinstall the new fuel pump, you will need to follow the instructions in the kit. The process is quite straightforward.

First, you will need to remove the four screws that hold the bracket on the old pump. Then, disconnect the electrical connection and the hose clamp before pulling off the old pump. Next, simply put the new pump in place, making sure to line up the bracket and connections correctly.

Once the new pump is in position, you can tighten the screws, hose clamp, and electrical connection. It is important to be careful and not over-tighten these connections, as this could damage the pump or the surrounding components.

After the new pump is secured, you can slide the tank back under the car and reconnect the fuel lines and electrical connections. Reconnect the negative battery cable and turn the key to the "On" position to check if the pump is working correctly.

Listen for the sound of the pump to ensure it is functioning properly. If you hear the pump running, this indicates a successful installation.

Finally, you can lower your car back down and take it for a test drive.

Frequently asked questions