F-250 / F-350 / F-450 2017–2019 LoadLifter 5000 Helper Spring Kit | Air Lift 57399

Stop rear sag, trailer sway, and bottoming out on a 2017–2019 Super Duty. The Air Lift LoadLifter 5000 kit (part #57399) adds up to 5,000 lbs of adjustable rear load support so the truck stays level when towing a fifth-wheel, running a gooseneck, or hauling a heavy bed load. These helper air springs work with the factory leaf springs, not instead of them, so you keep a usable empty ride and add support only when loaded. Air pressure is fully adjustable from 5–100 PSI.

Key features

• Up to 5,000 lbs of load-leveling capacity (never exceed the truck’s GVWR)
• Adjustable from 5–100 PSI for empty, partial, or max-load conditions
• 2-ply fabric-reinforced rubber bellows built like a tire
• Exclusive upper and lower roll plates protect the bags and help increase capacity
• Corrosion-proof nylon composite end caps that are steel-strong, lighter, and rust-free
• Under-frame, no-drill installation on most applications
• Quick-connect polymer air fittings with included air line and Schrader valve
• Works with most side-mount fifth-wheel and factory in-bed hitch systems
• Fits both single rear wheel (SRW) and dual rear wheel (DRW)
• Limited lifetime warranty

Fitment

• 2017–2019 Ford F-250 Super Duty 4WD
• 2017–2019 Ford F-350 Super Duty 4WD
• 2017–2019 Ford F-450 Super Duty 4WD pickup
• Compatible with 6.7 Powerstroke diesel and gas engines
• Rear axle / factory leaf springs

Fits trucks with no fifth-wheel hitch and most side-mount fifth-wheel or factory in-bed hitch applications. Does not fit 2WD models or cab & chassis trucks.

What’s in the box

• Pair of LoadLifter 5000 air springs
• Upper and lower roll plates
• Vehicle-specific mounting brackets and hardware
• Air line, fittings, and Schrader fill valve
• Illustrated installation manual

Notes & specs

• Compressor, in-cab gauges, and wireless controllers are not included
• Pair this kit with an Air Lift WirelessONE, LoadController, or similar onboard air system if you want to adjust pressure from the cab
• Brand/part number: Air Lift LoadLifter 5000 57399
• UPC: 729199573996
• Position: rear
• Capacity: up to 5,000 lbs
• Pressure range: 5–100 PSI
• Mount: under-frame
• Drilling: typically none
• Install time: about 1–2 hours
• Replacement spring: Air Lift 50293
• Kit weight: about 34 lbs
• Warranty: limited lifetime

Most 57399 kits bolt on with no frame drilling and install in roughly 1–2 hours with basic hand tools. Route the included air line to a convenient fill point at the bumper, bed, or license-plate area. Always set pressure for the load you are carrying and do not exceed the vehicle manufacturer’s GVWR. If your 2017–2019 F-250, F-350, or F-450 4WD squats when you hook up a trailer or load the bed, the Air Lift 57399 LoadLifter 5000 kit adds 5,000 lbs of adjustable rear support.