FASS HD Install Class 8

The FASS HD series designed for Class 8/Semis is available at Orange County Diesel in Huntington Beach, California. If you have any questions about any other FASS product, or if you need expert assistance installing your FASS HD, feel free to call and speak to a FASS service professional at 714-848-2170.

The FASS HD shares the same installation steps as the FASS Platinum for Class 8 applications. Please find the links to Part 3, Part 4, and Part 5 here.

Step 1: Installing electrical harness.
The installation of the electrical harness is done first, allowing power to be applied to the pump for lubrication purposes. Use of corrosion preventative spray and dielectric grease is recommended where electrical connection is made.

Select best location in firewall for passage of wiring harness from cab to engine compartment. Find or drill a 7/8” hole in firewall. Install RS-2684 grommet for ease of installation and protection of wire harness. Route red wire/ loom of the WH-1001 wire harness through the grommet in the fire-wall to the ignition or fuse panel.

Using a spade terminal, connect the "Red" lead to the "ON" terminal of the ignition switch on the circuit breaker board that is "hot" when the key is on.

Using a spade terminal, connect the green wire of the wire harness to the negative post of the battery or clean ground. Secure fuse out of the weather, then secure all electrical leads and harness.


The steps presented here in Part 2 are ONLY to be used as a guideline, as your application may be different.

Use thread tape or pipe sealant on ALL male pipe threads, do not use on male flared AN fittings.

Remove primary fuel and/or water separator. If primary filter is part of the fuel pump, ignore this step.

ONLY if a 90° fitting is to be used, follow these steps: Remove 4 bolts holding upside-down T Block pump assembly to the FASS filter base. Pay attention to the O-rings and ball. Remove fuel manifold and assemble 90° fitting directing it in the correct direction. Reassemble fuel manifold then pump assembly to FASS filter base, seating all O-rings & the ball in their proper place. Torque to 110 in./lbs.

Attach BR-2001 to back of system using the spacers and 1/4" bolts. Use the 2 shortest on the system base.

Position system where it will be mounted. Mark the 4 mounting points using the template located in the table of contents. Prior holes may be used. Drill these marked locations with a 13/32 bit.

Prior to installing pump, connect wire harness and turn on pump. Spray liberal amount of WD-40 or similar lube into water separator nipple. This wets the Gerotor and allows for easier initial priming. Assemble to frame using the (4) 3/8" bolts & flange nuts placing the RS-1001 between the frame and bracket.

Apply motor oil to O-rings located on filters. Attach to system and torque appropriately.