Motor Grader Parts and Components Explained for India

A motor grader is built from six part groups: the engine and driveline, the main frame with its articulation joint, the circle and drawbar that hang under the front frame, the moldboard with its cutting edge and end bits, the front axle, and the tandem housings that drive the rear wheels. Of all those parts, only a handful actually wear out and get ordered again — the cutting edge, the end bits, the circle wear inserts, the tyres, the filters and the oils.

This guide names every part the way a dealer’s parts counter names it, tells you which ones wear first on Indian road work, and gives the cutting edge sizes actually fitted to the 42 motor graders listed here. Knowing the correct name and size is most of the job: a parts order that says “blade” gets you a question back, and a parts order that says “152 x 16 mm cutting edge, 8 holes” gets you a price.

What are the main parts of a motor grader?

A grader looks complicated because everything hangs below the frame instead of sitting on top of it. Broken into groups it is straightforward.

Moldboard is the proper name for the blade — the curved steel plate that does the cutting. Most operators just say blade, and so does this guide where it reads better. For how these groups work together while grading, read how motor graders work.

What is the circle on a motor grader?

The circle is a large toothed steel ring bolted under the front frame, and the blade hangs from it. A small hydraulic motor drives a pinion gear against those teeth, and that is how the blade swings to any angle you want — right round to 90 degrees for bank cutting on some machines.

The circle sits inside a drawbar, the A-shaped or T-shaped frame that pulls the whole assembly along, and the two are held apart by replaceable wear inserts (some brands call them wear strips or shoes). Those inserts are sacrificial: they are cheap, soft steel meant to be worn away instead of the circle teeth, and replacing them on time is the single biggest thing you can do to keep a grader’s repair bill down. A worn-out circle is a very expensive repair; a set of wear inserts is not.

On many machines the circle drive gearbox holds its own small oil bath, listed on spec sheets as the circle reverse housing. It is a genuinely small reservoir — 1.5 to 27.5 litres across the machines listed here, most falling between 2 and 10 litres — and it is easy to forget at service time. Capacities for each machine are set out in the motor grader fuel and oil capacities reference.

The yoke is the ball-and-socket joint at the front of the drawbar where it attaches to the frame. It takes every bit of push the blade generates, so its ball and socket wear, and on older machines that wear shows up as a blade that will not hold a straight line.

What size cutting edge does a motor grader take?

The cutting edge is the replaceable steel strip bolted along the bottom of the blade. It is the part that actually touches the ground, and it is the part you will buy most often. It is sold by width and thickness in millimetres, and by the number and spacing of bolt holes.

Across the 42 motor graders listed on DesiMachines, 22 publish a cutting edge size, and they fall into just four widths.

Specifications are as listed on the machine pages at the time of writing. A few machines publish only the width — the Cat 120, 120 GC and 140 GC list a 152 mm edge without stating thickness — and the CASE 845B, 845C, 865B and 865C list two interchangeable edges rather than a size, which means the edge can be turned around and used a second time before it is scrapped.

Two practical points. First, width is not a choice, thickness sometimes is: the width and bolt pattern must match your blade, but many dealers stock a thicker edge in the same width for rocky work. Second, a curved or serrated edge is a different part from the flat one, and serrated edges are for breaking hard or frozen ground, not for a finish pass.

The moldboard plate behind the edge is a different figure again, running from 16 mm on the lighter machines to 50 mm on the largest listed, and it is not a wear part in normal use. If the plate itself is worn thin rather than the edge, the machine has been run with a finished edge for far too long.

What are end bits, and why do they wear faster?

End bits are the short, thicker pieces bolted at each end of the cutting edge, covering the corners of the blade. They wear faster than the edge between them for a simple reason: when you windrow soil, the material rolls off the leading corner, so that one corner does a lot more cutting than the middle of the blade.

Most operators change end bits roughly twice for every cutting edge, and the left and right bits are usually different parts, not a mirrored pair you can swap. If you let an end bit wear through, the damage moves into the moldboard corner itself — and that is welding and plate work, not a bolt-on replacement.

Order end bits in pairs, and order the bolts and nuts with them. Plough bolts have a countersunk head that sits flush so the head does not get ground off in the first hour, and the old ones are normally not worth refitting.

What is inside a tandem housing?

The tandem housings are the two long boxes carrying the four rear wheels, one each side. Inside each one is a heavy chain or a gear train running in an oil bath, driving both wheels on that side from a single output. That design is what lets the rear wheels climb over a bump one at a time while the frame — and so the blade — stays level. It is the reason a grader can leave a flat surface behind on ground that is not flat.

The distance between the two axles in a housing is the tandem wheelbase, quoted on most spec sheets. A longer tandem rides bumps better; a shorter one turns in a tighter space.

Inside, the wear parts are the chain (or gears), the sprockets and the oil seals at each wheel end. Tandem oil is not a frequent change, but it is worth checking: a housing that has been run low is an expensive rebuild, and the first sign is usually oil weeping past a wheel-end seal onto the rim.

What does the front axle do on a grader?

A grader’s front axle does two jobs an ordinary axle does not. It oscillates, meaning it pivots at the centre so both front wheels stay on the ground over uneven surfaces, and on most machines the wheels also lean — they tilt sideways under hydraulic control.

Wheel lean matters because a blade at an angle pushes the front of the machine sideways, and leaning the wheels into that push keeps the grader tracking straight instead of crabbing. The wearing parts here are the kingpins and bushes, the lean links and the tie rod ends. Loose kingpins show up as a grader that wanders, and a finish surface with a slight waviness in it.

Which motor grader parts wear out first in Indian conditions?

On Indian road and site work, in the order you will meet them:

Dust is the thread running through most of that list. A grader works in the dustiest air on site because it drags loose material along the ground in front of itself, and on dry ground in summer an air filter can load up in a fraction of its rated life. Check it daily, and do not blow a paper element out with the compressor — it damages the media and lets fine dust through to the engine.

The other thread is greasing. Pins and bushes at the drawbar, the yoke and the lean links carry heavy loads in gritty conditions, and they are the cheapest parts to look after and among the dearer ones to replace. The greasing points, grades and intervals guide covers what goes where.

How often should each part be checked or changed?

Machine service runs on hours, not months, because a grader that works 10 hours a day reaches its service far sooner than one that works two. The schedule below is the general pattern for construction equipment in India; your own machine’s operator manual is the final word, and it varies by brand.

Cutting edges and end bits do not fit that table, because they wear by material and hours of ground contact rather than engine hours. Inspect them daily and change them when the wear reaches the bolt holes — waiting past that point risks the bolts pulling through and the blade plate taking the damage.

A motor grader has more separate oil systems than most machines on a site: engine oil, hydraulic oil, transmission oil, final drives, tandem housings and, on many machines, the circle reverse housing. The full hour-by-hour breakdown is in the construction equipment service schedule.

What does a motor grader part cost?

Part prices are not published as a list, and any figure quoted without your machine’s details is a guess. Prices move with the brand, the part’s origin, the size of the machine and how many you order, and the same cutting edge can differ substantially between a genuine and an aftermarket supply. We quote parts against a specific machine rather than a price list — tell us the model and what you need and we come back with a price and a delivery time.

What is worth understanding is the choice you are making. Wear parts like cutting edges and end bits are commonly bought from good aftermarket suppliers, where the sensible test is the steel and the bolt pattern rather than the badge. Parts sealed inside a system — seals, pump parts, injectors, electronics — are where genuine or OEM supply earns its money, because a cheap part failing inside a hydraulic system takes far more than itself with it. The difference between genuine, OEM and aftermarket parts is set out in full separately.

When you order, have three things ready: the exact part name, the machine model and its serial number, and the quantity. The serial number is what separates two machines that look identical but took different parts in different production years.

Parts and servicing are part of what a grader costs to own, alongside the purchase itself. If you are weighing buying against hiring, the motor grader rental guide covers hire, and equipment finance options cover the purchase.

How do you check these parts before buying a used grader?

Two of the parts above carry real money on a used machine. Measure how much blade is left, and check the circle for play by swinging it and watching for movement against the drawbar — a tired circle group is the repair that turns a cheap grader into an expensive one. After that, look for neglect rather than age: weeping tandem seals, a rounded-off blade corner, missing grease nipples, hose repairs done with clamps. The full pre-purchase list is in the used motor grader buying guide.

Motor grader parts: the short version

The blade is called a moldboard, the ring it hangs from is the circle, the frame that pulls it is the drawbar, and the boxes carrying the rear wheels are tandem housings. The parts you will actually buy again and again are the cutting edge and end bits, the circle wear inserts, filters, tyres and oils. Cutting edges on the machines listed here come in 152, 203, 254 and 330 mm widths and 16 to 29 mm thicknesses — match the width and bolt pattern to your blade, and keep the serial number handy when you order.

Read next: how motor graders work for the mechanism behind these parts, motor grader blade angles for what the circle lets the blade do, and the motor grader guide for types, brands and applications. For the same breakdown on the other road-building machines, see bulldozer parts and road roller parts, or the full parts and running costs section.

Prices, specifications and features are indicative, vary by variant, location and date, and should always be confirmed with the official OEM or authorised dealer before any purchase decision. DesiMachines is not liable for decisions taken on the basis of information that may have changed after publication. Specification figures in this guide are taken from our listings at the time of writing.