Follow along with Wade as he installs the S&S Diesel LPK Plus on a 2022 Ford 6.7L Power Stroke, or use the step-by-step instructions below to complete the installation.

The factory under-hood fuel filter on a 2017-2026 Ford 6.7L Power Stroke uses a plastic housing that can become brittle over time. If that housing or one of its plastic connections fails, you can end up with a diesel fuel leak under the hood.

The S&S Diesel Motorsport Fuel Leak Prevention Kit, or LPK, replaces that factory filter assembly with a machined aluminum filter head and a metal Donaldson spin-on fuel filter. The kit also replaces the factory injector return connection with S&S Diesel’s aluminum Leak Prevention Fitting.

Shop S&S Diesel LPK and LPK Plus kits at Thoroughbred Diesel to compare the available options for your truck.

For trucks that still use the factory chassis-mounted fuel filtration system, the LPK Plus version also includes the replacement under-bed fuel filter so you can service both filters at the same time.

This guide covers installation on 2017-2026 Ford Super Duty trucks equipped with the 6.7L Power Stroke, using a 2022 truck as the example.

What Comes in the S&S Diesel LPK Plus?

The heart of the system is S&S Diesel’s machined aluminum filter head, which accepts a Donaldson P584171 spin-on fuel filter.

The kit also includes:

  • S&S aluminum fuel filter head
  • Donaldson P584171 spin-on fuel filter
  • S&S Leak Prevention injector return fitting
  • Fuel injection clamp
  • Mounting posts and mounting foot
  • New filter-head mounting hardware
  • Required O-rings and fittings

The 6.7F17-LPK-PLUS for 2017-2026 trucks also includes a Donaldson P585405 chassis-mounted panel fuel filter.

One of the benefits of converting to the S&S LPK is easier future fuel filter service. Once the conversion is installed, you can replace the engine-mounted spin-on filter instead of replacing the complete factory-style plastic filter assembly. Thoroughbred Diesel carries the S&S Diesel replacement LPK engine-mounted spin-on fuel filter for 2011-2026 6.7L Power Stroke trucks.

Important Torque Specs

Keep these specifications handy during the installation:

  • S&S short mounting post: 89 lb-in (10 Nm)
  • Mounting foot/OEM mounting bolts: 89 lb-in (10 Nm)
  • Filter-head mounting bolts: 89 lb-in (10 Nm)
  • Injector return hose clamp: 9 lb-in (1 Nm)
  • 2017-2026 chassis filter housing bolts: 44 lb-in (5 Nm)

Important: Do not confuse inch-pounds with foot-pounds. Most of the fasteners used during this installation require relatively little torque.

Before You Begin

Park the truck on a level surface and allow the engine to cool.

S&S recommends disconnecting the negative battery cables from both batteries before beginning the installation.

Place shop towels underneath the engine-mounted fuel filter before disconnecting anything. Residual diesel fuel will remain inside the filter and fuel lines, so some leakage is normal when the connections are removed.

It is also a good idea to have a catch container available before servicing the chassis-mounted filter.

Step 1: Disconnect the Factory Fuel Lines

Start with the engine-mounted fuel filter under the hood.

On 2017-2026 trucks, three fuel connections attach to the factory filter.

Tank Supply Line

The white locking clip on the tank supply connection has three positions:

  1. Locked
  2. Middle
  3. Fully unlocked

Pinch the two white tabs together and move the clip completely into the unlocked position before pulling the line from the filter.

Expect some residual fuel to drain from the line.

Fuel Supply Line

Release the safety connector on the middle fuel line and carefully pull the connection away from the filter.

These factory lines contain plastic components, so avoid pulling, twisting, or forcing them unnecessarily.

Injector Return Line

Release the green locking mechanism on the injector return line.

A small pick can help lift the lock if necessary, but be careful not to damage the connector or hose.

Once all three connections are released, move them aside.

Step 2: Remove the Factory Fuel Filter

Rotate the factory filter assembly counterclockwise.

Once it reaches its release position, lift the filter upward and out of the factory mounting bowl.

Set the filter aside and keep shop towels underneath the area to catch any remaining diesel fuel.

Step 3: Remove the Factory Filter Bowl

The factory filter bowl is secured by four bolts.

Two of these bolts will be reused with the S&S mounting system, so keep track of them during removal.

One of the more difficult bolts is located underneath the metal fuel supply line.

Instead of pulling aggressively on the line for access, remove the bolt retaining the factory fuel line isolator and gently rotate the metal line upward. This provides enough room to access the bolt underneath it.

Remove all four mounting bolts and lift the factory filter bowl from the engine.

Step 4: Modify the Injector Return Line

One of the biggest improvements in the S&S kit is the replacement of the factory plastic injector return connection.

Remove enough of the protective sheathing to expose the hose near the factory connector.

Locate the lowest point of the molded plastic fitting and cut the injector return hose approximately 1/4 inch below the plastic connector.

It is better to leave the hose slightly too long than to cut it too short.

On 2020 trucks, S&S specifically warns against cutting more than approximately 1 inch below the factory connector, since this can leave the return hose too short.

Trim the protective sheathing as necessary so there is room for the supplied hose clamp.

Slide the S&S fuel injection clamp over the hose.

Next, remove the S&S Leak Prevention Fitting from the filter head by pulling the blue collar backward.

Apply a small amount of clean oil to the barbed portion of the fitting and push the fitting completely into the injector return hose.

Make sure the barb is fully seated before positioning the clamp.

Tighten the clamp until the two ears are approximately parallel. Very little clamping force is required.

S&S specifies approximately 9 lb-in (1 Nm) and recommends maintaining roughly a 1/8-inch gap between the inside edges of the clamp ears.

Do not overtighten the clamp.

Route the injector return hose inboard of the CCV hose and reposition the factory clips as necessary so the hose does not rub against surrounding components.

The upgraded connection is also available separately. If you need the fitting without purchasing the complete filter conversion, check out the S&S Diesel Fuel Leak Prevention Fitting for 2017-2026 Ford 6.7L Power Stroke trucks.

Step 5: Install the Rear S&S Mounting Post

Install the S&S short mounting post into the correct rear mounting boss where the factory filter bowl was previously mounted.

If the CCV assembly is removed, you may notice another threaded boss nearby. Do not use the adjacent boss.

Torque the short post to:

89 lb-in (10 Nm)

A 16mm or 5/8-inch socket can be used.

Step 6: Install the S&S Mounting Foot

Reinstall the difficult-to-access OEM bolt underneath the metal fuel supply line, but only start it a few threads.

Do not tighten it yet.

S&S designed the mounting foot with a slot specifically so you do not have to completely remove and reinstall this bolt while working underneath the fuel line.

Slide the slotted portion of the mounting foot underneath the bolt head.

Snug the bolt enough to hold the mounting foot while still allowing the bracket to rotate.

Rotate the mounting foot until the raised mounting pad lines up naturally with the factory fuel line bracket.

Before torquing anything, temporarily place the S&S filter head across the two mounting posts.

Verify that both filter-head mounting holes line up without forcing the assembly into position.

Once everything is aligned, torque the mounting foot bolt to:

89 lb-in (10 Nm)

Using a 1/4-inch wobble extension can make reaching this bolt much easier.

Step 7: Reattach the Fuel Line Bracket

Use the retained factory bolt to attach the OEM fuel line bracket to the raised pad on the S&S mounting foot.

Wade recommends initially leaving this bolt slightly loose so the fuel lines retain a little movement while you connect them to the new filter head.

This can help prevent unnecessary stress on the factory lines.

Once the lines and filter head are correctly positioned, torque the bolt to:

89 lb-in (10 Nm)

Step 8: Install the Donaldson Spin-On Filter

Lubricate the seal on the Donaldson P584171 spin-on fuel filter.

Thread the filter onto the S&S filter head until the seal barely contacts the filter head.

From that point, tighten the filter another:

1/2 to 3/4 turn

Do not overtighten the filter.

S&S specifically notes that tools should not normally be necessary for installation. Overtightening can make the filter significantly harder to remove during future service.

When it’s time for your next fuel filter service, you can order the S&S Diesel replacement LPK spin-on fuel filter individually from Thoroughbred Diesel.

Step 9: Mount the S&S Filter Head

Place the assembled filter head and spin-on filter onto the two S&S mounting posts.

Install the two supplied 10mm-head filter mounting bolts.

Torque both bolts to:

89 lb-in (10 Nm)

If the middle factory fuel line does not naturally align with the filter head, S&S notes that it may be easier to connect the fuel lines before completely tightening the filter head.

Do not force the connection at an angle. The connector contains O-rings that can be damaged if the line is installed incorrectly.

Step 10: Connect the Fuel Lines

Connect the factory fuel lines to the new S&S filter head.

Wade’s preferred sequence is to start with the middle connection.

Middle Fuel Line

Align the fitting straight with the port and push it completely into place.

Lock the safety clip.

Tank Supply Line

Place the white locking clip into its middle detent before installing the connector onto the new filter head.

Push the connection fully onto the port and lock the clip.

Avoid putting unnecessary tension on the plastic fuel line.

Injector Return Line

Make sure the blue collar on the S&S Leak Prevention Fitting is pulled backward toward the 90-degree bend.

Push the fitting onto the filter-head port until it clicks into place and the collar locks forward.

Give each fuel connection a light tug to verify that it is fully locked.

Step 11: Finalize the Under-Hood Installation

Before moving on, verify that:

  • Both filter-head bolts are torqued to 89 lb-in.
  • The S&S mounting post and mounting foot bolts are torqued to 89 lb-in.
  • The factory fuel line bracket is secured and torqued.
  • None of the fuel lines are kinked or under unnecessary tension.
  • The injector return hose is routed away from rubbing points.
  • All three quick-connect fittings are completely locked.

At this point, the engine-mounted portion of the S&S LPK installation is complete.

Installing the LPK Plus Chassis-Mounted Filter

If you purchased the S&S LPK Plus and your truck still uses the factory chassis-mounted fuel system, you can replace the under-bed filter while the fuel system is already being serviced.

The 2017-2026 LPK Plus kit includes the Donaldson P585405 panel filter.

If your truck already has an aftermarket fuel system that replaces the factory chassis filtration, such as an AirDog or FASS system, you may only need the standard LPK. You can compare S&S Diesel LPK options here.

Step 12: Prepare the Chassis Fuel Filter

Place a large drain pan underneath the fuel conditioning module.

S&S recommends performing this service with less than half a tank of fuel when possible to reduce the chance of fuel siphoning.

Disconnect the Water in Fuel sensor electrical connector and move the harness away from the area where diesel fuel will drain.

Step 13: Lower the Filter Housing Before Draining

This step is important.

The 2017-2026 filter assembly uses a check valve in the fuel conditioning module.

Do not simply open the water drain before lowering the filter housing.

Doing so can allow the fuel tank to siphon through the module.

Instead, use an 8mm socket to loosen the five captive bolts holding the filter cover.

Slowly lower the cover and filter assembly enough to disengage the filter from the internal check valve.

Once the check valve closes, the remaining fuel can drain safely from the housing.

Step 14: Replace the Panel Filter

Remove the cover and filter assembly.

The filter is retained by tabs inside the cover.

Slide the filter sideways toward the drain valve to release it while keeping the cover stationary.

Remove the old rubber seal from the cover.

Install the supplied new seal. Lubricating it lightly with clean engine oil or a suitable O-ring lubricant can make installation easier.

Install the new Donaldson P585405 filter by sliding it into the cover in the opposite direction from removal until it is properly retained.

Step 15: Reinstall the Chassis Filter Housing

Position the cover and filter assembly back onto the fuel conditioning module.

Tighten the five captive bolts evenly.

Torque them to:

44 lb-in (5 Nm)

Reconnect the Water in Fuel sensor.

Step 16: Prime the Fuel System

Do not immediately start the engine after replacing the filters.

The low-pressure fuel system must first be primed.

Turn the ignition to the ON position for approximately 30 seconds, but do not start the engine.

Repeat this process at least five times.

On trucks equipped with push-button start, press the start button without pressing the brake pedal. This powers the truck and allows the lift pump to run without cranking the engine.

While priming, inspect the entire installation for leaks.

Check:

  • The Donaldson spin-on filter seal
  • All three connections at the S&S filter head
  • The new injector return fitting
  • The chassis-mounted filter housing
  • The Water in Fuel sensor area

You may hear fuel and air moving through the system during the first several cycles. This is normal as the filters fill.

Step 17: Start the Engine and Check for Leaks

After completing at least five priming cycles, start the engine.

Allow it to idle while inspecting the entire fuel system again.

If the engine starts and immediately dies, repeat the complete five-cycle priming procedure before attempting to start it again.

If you hear persistent gurgling or cavitation from underneath the truck, shut the truck down and recheck the chassis-mounted filter. An improperly sealed chassis filter can allow air into the system without necessarily producing a visible fuel leak.

Once the truck runs normally and the system remains dry, the installation is complete.

Why Install the S&S LPK on a 6.7L Power Stroke?

The S&S Diesel Fuel Leak Prevention Kit addresses one of the more vulnerable components in the 6.7L Power Stroke fuel system.

Instead of relying on the factory plastic under-hood fuel filter assembly, the LPK gives you:

  • A machined aluminum S&S filter head
  • A metal Donaldson spin-on fuel filter
  • A more robust injector return connection
  • Easier future under-hood fuel filter changes
  • Factory-compatible filtration without the disposable plastic filter housing

For trucks still using the OEM chassis-mounted filtration system, the LPK Plus also gives you the proper standalone under-bed filter so both filters can be serviced without purchasing another factory-style two-filter package.

If you’re looking to eliminate the factory plastic engine-mounted fuel filter on your 2017-2026 Ford 6.7L Power Stroke, the S&S Diesel LPK is a straightforward upgrade that also makes future fuel filter service easier.

Ready to upgrade? Shop S&S Diesel LPK and LPK Plus kits at Thoroughbred Diesel.

Already have an LPK installed? Keep these replacement parts handy for future service:

For additional technical information, you can also review the official S&S Diesel LPK installation instructions.

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By: Wade