Detroit Diesel — Installation of High Pressure Fuel Line and Transfer Tube
Repair & overhaul
From a Detroit Diesel service manual — check it applies to your exact model before use.
Before you start
- Ensure the engine has been shut down for a minimum of 10 minutes before servicing any component within the high pressure circuit.
- Always discard and replace the old high pressure fuel line and transfer tube — one-time use components.
- Do NOT loosen any high pressure fuel injector line nuts for priming; use the priming port on the fuel filter housing.
- Do NOT re-torque high pressure fuel injector line nuts.
Procedure
- Apply a light coat of clean engine oil to the transfer tube O-ring and install transfer tube into the cylinder head.
- Using a 24 mm socket, torque the thrust nut to 45 N·m (33 lb·ft).
- Align the new high pressure fuel injector line fittings to the transfer tube and unit pump.
- Hand tighten the line nut at the unit pump first, then at the transfer tube.
- Draw a vertical line along the front edge of both nuts and up the fuel line.
- Using a 17 mm fuel line wrench, tighten the unit pump end nut through 120 degrees.
- Hold the transfer tube thrust nut; tighten the transfer tube end nut through 120 degrees.
- Install the damper clamp and mounting bracket; torque bracket bolts 25 N·m and damper clamp 12 N·m.
- Install the air intake manifold and cylinder head cover.
- Prime the fuel system and run the engine; check for leaks.
Tools required
- J-47483 17 mm fuel line wrench Amazon
- J-47484 24 mm fuel line wrench Amazon
- J-45063 24 mm fuel line wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Transfer-tube thrust nut 45 N·m (33 lb·ft)
- High pressure fuel line mounting bracket bolts 25 N·m (18 lb·ft)
- Damper clamp bolt and nut 12 N·m (9 lb·ft)
- Fuel line nut turn at each end 120 degrees
Source: Detroit Diesel service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.