Hydraulic Dump Bed Conversion for Kei Trucks

I've installed dump kits on two kei trucks now — my Hijet and a buddy's Carry. The first one took me six hours and a lot of swearing. The second took three hours. Here's everything I learned so you can skip the swearing part.

Why Add a Dump Bed

If you haul anything regularly — mulch, gravel, soil, firewood, feed — a dump bed changes your life. Instead of shoveling material out of the bed (which takes 20-30 minutes and destroys your back), you flip a switch and gravity does the work in 10 seconds.

For landscapers, farmers, and property owners, it's the single best kei truck mod. Period.

Kit Options

There are three types of dump kits that work on kei trucks:

Electric/Hydraulic Kits ($600-$900)

The most common and what I recommend for most people. These include:

• A 12V hydraulic pump that runs off your truck's battery
• A hydraulic cylinder
• Mounting brackets
• A wired remote switch
• Hydraulic fluid

You wire the pump to your battery, mount the cylinder between the frame and bed, and control it with a toggle switch. The bed tilts backward when activated.

Scissor Lift Kits ($800-$1,200)

Instead of a single cylinder, these use a scissor mechanism that lifts the bed straight up. Advantages: more lift height, more stable when fully raised. Disadvantages: more complex install, heavier, more expensive.

Manual/Mechanical Dump ($200-$400)

A simple pivot point with a latch. You manually push the bed up (or use a hand crank). No electrical or hydraulic components. Cheapest option but requires physical effort.

What I Recommend

For most kei truck owners: the electric/hydraulic kit in the $700-800 range. It's the sweet spot between cost, complexity, and capability. The cheap $400 kits on Amazon work but the pumps are louder and slower. The $800+ kits have better pumps that lift faster and quieter.

Installation Overview

I'm not going to write a full step-by-step here because every kit has its own instructions and every truck bed mounts slightly differently. But here's the general process:

Step 1: Remove the tailgate latch mechanism. The bed needs to be free to swing on the rear hinges. Most kei trucks use the rear of the bed as a hinge point — you're just adding the lift mechanism at the front.

Step 2: Mount the cylinder bracket to the frame. This is the hardest part. You need to find a solid frame point near the front-center of the bed. Drill through the frame, bolt the bracket. Use Grade 8 bolts — this is structural.

Step 3: Mount the upper bracket to the bed floor. Same deal — drill, bolt, reinforce. The bed floor is thin sheet metal, so you'll want a steel backing plate to distribute the load.

Step 4: Install the hydraulic pump. Mount it somewhere protected — under the bed, behind the cab, or in the engine bay. It needs to be accessible for maintenance but protected from road debris.

Step 5: Wire it up. Positive wire to the battery (with an inline fuse — 30A minimum). Ground to the frame. Switch in the cab, wherever you can reach it.

Step 6: Fill with hydraulic fluid and test. Cycle the bed up and down 10 times to bleed any air. Check all bolts after the first few uses.

Real-World Results

My Hijet dump bed has probably cycled 500+ times over two years. Here's what I can report:

• Lift time: About 8 seconds from flat to full dump angle
• Dump angle: Approximately 45 degrees — plenty for gravel, soil, mulch
• Battery draw: Noticeable but not problematic. The pump runs for less than 10 seconds per cycle.
• Maintenance: Check hydraulic fluid level every few months. Replace fluid annually. That's it.
• Issues: The pump gets slower in cold weather (below 20F). Thicker hydraulic fluid helps.

What to Watch Out For

1. Weight distribution when raised. A loaded bed at 45 degrees shifts a LOT of weight to the rear axle. Don't dump on a slope unless your wheels are chocked.

2. Bed flex. Kei truck beds are thin. Under heavy loads with the dump raised, the bed can flex. If you're dumping heavy material regularly, consider adding a steel cross-brace under the bed.

3. Clearance. Make sure nothing behind the cab interferes with the bed as it rises — light bars, rear window, exhaust stack.

4. Tailgate pins. Your tailgate needs to swing freely when dumping. Replace the fixed latches with quick-release pins so you can open the tailgate before activating the dump.

Cost Breakdown

Best $800 I've spent on any vehicle. If you haul anything, this pays for itself in saved time and back pain within a month.