Light Duty and Medium Duty Dump Kit Installation Overview

Install Guide

Dump Kits · 8 min read · 3 videos

Install Guide

This guide walks you through installing the Pierce light duty dump bed kit on a Chevrolet cab and chassis with a 60-inch cab-to-axle measurement. The installation uses a custom 10 ft bed to accommodate the rear hinges — slightly longer than the standard 9 ft bed for this truck size.

Dump Kits · 8 min read · 3 videos

⚠ Expert installation required. This kit requires welding, mechanical, and electrical skills. If you lack the tools or experience, consult a licensed converter. Modifications vary by truck make and model. Call us at 800-658-6301 for support.

Part 1: Pre-Installation and Measurements

Part 1 — Pre-installation measurements, chassis prep, and hinge placement

Shortening the Chassis

To maximize bed overhang for enhanced lifting strength, shorten the chassis frame as follows:

Remove taillights and inspect the chassis rear.
Cut the frame near the rearmost cross member at a 45° angle. This allows pin clearance while providing metal for welding or bolting the rear hinge.
Weld the rear hinge to the frame. Avoid welds forward of the rear frame hanger to prevent cracks or weak spots. Bolt the front of the frame hanger to the chassis.

Rear Hinge Placement

Position the rear hinge in the slot between the outer frame and the cross member.
Ensure sufficient clearance for hinge pins and secure the hinge to the chassis.

Scissor Assembly Placement

Measure 5 ft 8 in to 6 ft 6 in from the rear hinge to the scissor assembly's cross member pin.
For this build, place the scissor assembly at 5 ft 11.5 in due to clearance issues with the front fuel tank filler hose on the Chevrolet.
Bolt L-brackets to the frame using existing overload spring perch bolt holes. Sandwich them with longer bolts to secure the scissor assembly.

Bed Height Considerations

Account for the fuel filler hose thickness. This is specific to Chevrolet — Ford and Dodge may allow lower bed placement.
Maintain a 2 in gap between the bed sill and chassis frame to ensure clearance for the fuel filler hose in the lowered position.

Cross Member Modifications

Trim the cross member to fit the 34 in frame width, allowing room to weld it to the L-brackets without damaging the truck frame.
Use existing bolt holes to secure the L-brackets, preserving chassis integrity.

Front Frame Hinges

Add spacers if needed to achieve proper clearance between the chassis frame and bed sill.
Trim the sill support to fit inside the bed's main runner for optimal alignment.

Verifying Measurements

Component	Dimension
Bed sill	4 in
Cross member	3 in
Bed deck to chassis	7 in total
Rear hinge spacer	2.5 in
Overall height	9.5–10 in
Fuel tank vent clearance	1–1.5 in

Adjust the scissor assembly position if needed, noting constraints like fuel tank placement.

Part 2: Wiring Connections

Part 2 — Pump wiring, battery connections, and cab switch installation

Wiring Kit Components

Positive (red) and negative (black) battery cables for direct battery connection
Hydraulic hose, switch, wiring, and hardware for pump mounting

Pump Installation

Fabricate a bracket to mount the pump in a safe location — inside or outside the frame, behind the seat, or in a weather-protected area.
Use Teflon paste or suitable pipe sealant for the 90° fitting. Remove the control valve solenoid coil (the black plastic square) to install the fitting. Make sure the hose avoids contact with the muffler, tailpipe, or moving parts.
Reattach the solenoid coil after securing the fitting.

Wire Color Reference

	Yellow — Coil (down function)
	Green — Motor solenoid small post
	Red — Power supply post on solenoid
	Black — Ground post on motor

The brown wire is not used in this installation. The customer requested operation only when ignition is on for safety.

Battery Connections

Connect the red positive cable to a 150 amp breaker, then to the battery.
Secure the negative cable directly to the battery for a reliable ground.
Use the included #4 welding cables. Secure them every 12–15 in to prevent wear from wind or debris.

Cab Controls

Drill a 1/2 in hole in the cab to install the momentary on/off switch (spring-loaded to center).
Connect the green wire to the bottom screw and the yellow wire to the top screw on the switch.
Reroute the brown wire to the vehicle's fuse box (ignition-powered position) for key-activated operation.

Part 3: Dump Bed Installation

Part 3 — Hinge installation, tack welding, frame brackets, and final assembly

Hinge and Frame Assembly

Use two hinge pins (or one large pin for added strength) to secure the rear hinges.
Tack weld all components to ensure proper alignment before final welding.
Bolt L-brackets to the frame behind the overload spring bracket using pre-drilled holes and grade 8, 1/2 in bolts with self-locking nuts.
Trim the cross member slightly short to facilitate welding to the L-brackets.

Scissor and Sill Support

Build a bracket to support the scissor assembly in the lowered position. This prevents long-term sagging.
Slide sill supports into the 4 in channel iron under the bed. Secure with two 1/2 in grade 8 bolts per side.

Bed Guides

Fabricate a cross member in front of the scissor assembly. Weld guides to it and bolt it to the frame using existing holes.
Countersink bolts to prevent interference with the bed in the lowered position.

Under-Bed Modifications

Perform a dry fit to check clearance for cross members or rear hitches. Trim rear hinges if needed — especially for non-standard bed lengths like a 10 ft bed on a 60 in cab-to-axle truck.
Mark and pre-drill holes for sill supports and tie-down brackets before final installation.

Drilling and Final Fit

Mark hole locations with a paint marker and pre-drill to avoid working under a raised bed.
Trim one or two under-bed cross members to accommodate the scissor assembly in the lowered position.
Ensure the bed contacts all four corners with rear hinges flush against the bed sill and proper front-to-rear alignment.
Weld the rear hinges and bolt the front cross member for secure attachment.