Used Motor Graders: It's All About the Blade and the Tandem Drive

May 21st, Nansha inspection yard. A 2016 XCMG motor grader, GR165, sold to a Zambian customer, going through one more inspection before shipping.

This customer maintains mining-area roads. He's bought two road rollers from me, but this is his first grader. On the video call he asked how a grader differs from a bulldozer. I told him: a bulldozer does rough work; a grader does embroidery.

Excavator operators look down on grading, calling it low-skill work. Wrong. A grader does precision work — the last three centimeters of a roadbed are all shaved by it. Slightly off condition and the surface comes out wavy, and asphalt won't hide it.

Grader inspection comes down to two things: the blade and the tandem drive. This piece lays it all out.

Graders are a niche and few people know how to inspect them — and precisely because it's a niche, the market is full of dressed-up junk. The year before last I bought one showing 6,000 hours; the blade was worn to the root and the tandem drive oil was black as soy sauce — real hours at least double. Since then I've written a standalone grader inspection process, more detailed than the excavator one.

Measure Blade Wear First

The blade is a consumable, but it's also a mirror that shows the truth. A new blade is 150 mm wide; down to 110 mm, it's due for replacement.

This grader's blade measured 104 mm — past the line. Measuring is simple: caliper at the middle, then both ends. The middle wearing faster than the ends is normal, but a gap over 8 mm means the moldboard angle was never adjusted right — or the operator was too lazy to adjust it.

A domestic blade set costs RMB 1,800 — cheap. But a blade worn this far and still in service tells you the last owner skimped on maintenance. On a poorly maintained machine, look at everything else twice as carefully.

Circle and Drawbar

The moldboard rides on a big rotating circle; the circle turns, the blade angle changes. The check: rotate the circle through the full 360 degrees, listen for binding, look at gear ring wear.

This grader gave a dull thud around 180 degrees. Opened up, half the circle's brass bushings had shattered, and brass chips had fallen into the teeth. A bushing set is RMB 650 — but chips in the gear ring had scored the tooth faces, and that damage can't be repaired. The whole circle has to be replaced: RMB 12,000.

Shake the drawbar ball joint too. With too much play, the blade wanders and the graded surface comes out alternating deep and shallow.

After the static checks, test the actual grading. Level a 30-meter stretch in the yard, drop the blade, run two passes, then walk the graded surface. Flat means a good machine; ridges mean go back to the circle and ball joint. This grader cut flat, ridge deviation within 3 mm — pass.

Plenty of inspectors skip the grading test — too much trouble. A grader that never touches dirt hasn't been inspected. Same as buying a used car without driving it: idling in place tells you nothing real.

The Tandem Drive Is a Grader's Life

A grader's rear axle is a tandem drive with chain drive on both sides — a completely different animal from a truck axle. Loose chains and pointed sprocket teeth mean the blade shudders the moment it bites hard soil.

The check: jack up the rear, neutral, spin the wheels by hand and feel the chain slack. Then drive slowly a short stretch, get under, and listen. A healthy tandem hums; clicking means the sprockets have worn to points.

This grader had a faint click on the right side. Opened the oil sump: glitter in the oil. Lao Li said it's good for another 5,000 hours, but the price had to move. We eventually took RMB 9,000 off.

On that glitter — many sellers won't let you open the sump. If they won't, better to walk away from the machine.

Articulation and Tires

A grader articulates in the middle, up to twenty degrees. A worn articulation bearing makes even driving straight a chore. The check: swing the articulation full left and full right in place, look for seepage at the joint, listen for bearing noise.

Six tires, 1400 size, RMB 3,200 each. This grader's two rear tires had 30% tread left; I replaced them before shipping and didn't charge the customer. Tire money isn't where you save — replacing them in Zambia, the freight would cost more than the tires.

I listened to the engine in passing. Fired on the first crank from cold, steady idle, no blue smoke from the stack. The last owner skimped on maintenance, but not on the engine — oil changes were frequent and the sump was clean.

Checked the cab too. Half the seat foam had collapsed, and two dash lights were out — one dead bulb, one loose wire. Minor stuff: listed in the report, fixed before shipping, RMB 160.

Before Shipping

The grader shipped June 2nd. In the report I attached photos of the bushings, sprockets, and tires, plus the repair record for the circle replacement.

Shipping day, the customer watched the loading over video. The machine drove into a 40-foot flat rack, wedged fore and aft with chocks, blade dropped to the floor. When it was done he said: "Your inspection is more thorough than the supervisor I hired." I like hearing that — but I'd rather he come back for another machine next year.

Graders are a niche and few inspect them. All the more reason to write the rules down plainly. When you inspect a grader, remember the order: blade, circle, tandem drive, articulation, tires. One by one. Don't skip.