Replacing Fuel Filters: Step-By-Step Guide For Fass Systems

Changing the FASS fuel filter and water separator on a diesel truck can be a tricky process. There are a few methods to prime the FASS pump, including filling the filters, screwing them on, and running the pump, or wrapping the service port in rags and pushing the Schrader valve with a screwdriver. It is also important to consider the history of the vehicle and the quality of fuel when changing the filters.

Filling new canisters with old fuel

However, if you choose to fill new canisters with old fuel, there are a few things to keep in mind. Firstly, it is important to know the history of the vehicle and the fuel. If the fuel has been sitting in the old canisters for a long time, it may have degraded in quality and may not perform as well as fresh fuel. Additionally, if the old fuel is contaminated, it could damage the new canisters or the engine of the vehicle.

Another thing to consider is the amount of old fuel you have. If you do not have enough to fill the new canisters, you will need to add fresh fuel to top them up. Mixing old and new fuel is not ideal, but it is better than using all old fuel if its quality is questionable.

When filling the new canisters with old fuel, work in a well-ventilated area and take the necessary safety precautions. Wear proper safety gear, such as eye protection and gloves, to protect yourself from any spills or accidents.

• Place the new, empty canisters on a level surface to ensure stability.
• Attach any necessary stabiliser legs to the canisters.
• Weigh the old fuel in its current container to determine how much you have.
• Calculate how much fuel you need to fill the new canisters.
• Pour the old fuel into the new canisters, being careful not to overfill them.
• If you do not have enough old fuel, top up the new canisters with fresh fuel.
• Securely tighten the caps on the new canisters to prevent leaks.
• Label the new canisters with the date and any relevant information about the fuel.

Remember, it is always best to use fresh fuel when possible to ensure optimal performance and avoid any potential issues with your vehicle.

Pouring fresh fuel into new canisters

When changing the FASS fuel filter and water separator on a diesel truck, it is recommended to use fresh fuel to pour into the new canisters before screwing them in place. This is because you may not know the history of the vehicle, including how long the filters have been in place and the quality of the fuel. By using fresh fuel, you can avoid the risk of contaminating the new filter with old or poor-quality fuel.

To do this, first, make sure you have fresh, clean fuel ready. It is recommended to have diesel in a fuel can. Open the new canisters and gently pour in the fresh fuel. Do not fill them to the brim, just enough so that the filters are adequately soaked. Once this is done, screw the new canisters in place, following the manufacturer's instructions or a mechanic's advice.

It is important to note that simply pouring fuel from the old canisters into the new ones may not be advisable, as it could defeat the purpose of changing the filters in the first place. Additionally, pouring fuel out of the old canisters can be messy and counterproductive, especially when dealing with the water separator.

Remember to take appropriate safety measures when handling fuel, and it is always best to consult a professional mechanic or refer to the vehicle's manual for detailed instructions on changing the FASS fuel filters and canisters.

By following these steps and guidelines, you can ensure that your diesel truck's FASS fuel filters are properly maintained and that your vehicle runs efficiently.

Using contaminated fuel

When replacing the FASS fuel filter and water separator on a diesel truck, it is recommended to use fresh fuel when pouring into the new canisters before screwing them in place. This is because you may not know the history of the vehicle, including how long the filters have been in place and the quality of the fuel. Using contaminated fuel could lead to injector wear, reduced performance, and fuel system damage.

FASS Fuel Systems replacement filters are designed specifically for FASS fuel pumps to ensure optimal filtration and performance. These filters are crucial for maintaining the quality of diesel fuel as they help remove contaminants, water, and air that could otherwise cause issues.

To avoid these issues, it is important to use clean, fresh fuel when replacing the FASS fuel filters. It is also recommended to replace the filters regularly and to use high-quality fuel that meets the specifications of your vehicle. By following these practices, you can help ensure optimal fuel system performance and maintain the health of your engine.

Preventing air in the system

When changing FASS fuel filters, it is important to take steps to prevent air from entering the system. This is because air in the fuel system can cause issues with starting your vehicle and keeping it running. Here are some tips to prevent air in the system when changing FASS fuel filters:

• Fill both filters before screwing them on and then run the pump. This will help to bleed the air out of the system.
• Crack the front filter (not the water separator) so that fuel leaks/sprays out. Then, tighten the filter when a steady flow and sound come from the pump. This method can be messy, so it is recommended to have a bucket handy.
• Make sure you have at least 5 gallons of fuel in the tank. If you do not have enough fuel, you may see small air bubbles constantly.
• Wrap the service port with a rag or two and push the Schrader valve with a screwdriver while pumping. This method can help prevent a mess and any hesitation to start.
• Use fresh fuel to fill the canisters before screwing them in place. This ensures that you are not pouring contaminated or poor-quality fuel into the new filter.
• Check your owner's manual for information on filter replacement intervals and follow the recommended schedule.
• Be sure to release fuel system pressure before replacing the filter. This can be done by pulling the fuel pump fuse and running the engine until it shuts off. Always exercise caution when working with gasoline and have a fire extinguisher nearby.

Bleeding with the factory primer

When bleeding with the factory primer, it is recommended to replace all filters without pre-filling any of them. Wrap the service port with a rag or two, then push the Schrader valve with a screwdriver while pumping. This method is mess-free and will not cause any hesitation to start.

Alternatively, you can fill both filters, screw them on, and run the pump. Then, crack the front filter on the FASS (not the water separator) so that fuel leaks or sprays out. Tighten the filter when a steady flow and sound come from the pump. This method is messier and requires a bucket, but it ensures that all air is bled out of the FASS, making it run as quietly as possible.

If you are using a FASS 150 pump/filter, you can simply turn the ignition to the second (pre-start) position and let the pump prime the filter for you. Just remember to crack the bleeder to remove the air until fuel comes out.

Another option is to use a fuel primer such as the Reverso FP-301. This device pumps diesel fuel from the tank through the fuel lines, pushing air from the main feeding line, primary filters, secondary filters, and engine. It includes integrated pressure relief valves to protect fuel system components and can be installed by simply splitting a fuel line and connecting each end to the unit.

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