There are two types of motor grader on the market, and from the operator’s standpoint, they couldn’t be more different.
The first is the modern type, which has been wired with a computer network that ‘talks’ to the various hydraulic valves to ensure that the machine’s operation is no more complicated than moving two electromechanical joysticks to sculpt the sand into beautiful shapes.
The other type, which is far more common in the Middle East, resembles a Victorian railway signal box, as it has a bank of about two-dozen spindly levers that need to be pulled gently and at a precise moment in order to achieve the desired grade.
It is without doubt the most difficult machine on site to operate, and this is one of the reasons why the purchaser has to be especially fussy about the condition of a unit’s hydraulic system.
If you are looking at a used motor grader in the Middle East, the chances are that it will have the word ‘Caterpillar’ written on it, and ‘14G’ somewhere alongside. If you just need a second grader and don’t want to pay too much for it, you might want to consider other brands as they can sell for under two thirds the price of an equivalent Cat machine.
Whatever model or spec you choose, the principles of inspection remain the same.
Firstly, ensure the machine is parked on the level. Next, walk around the back and look at the machine to see if it is leaning to one side. Take a tape measure and check the distance from the tandems to the frame for all rear wheels. These readings should be consistent.
The moldboard should also be examined carefully. All cutting edge bolts should be present – if any are missing it is a sign of patchy maintenance – and the board itself should have good edges, both on its top and its bottom.
According to auction house IronPlanet, the circle takes particularly heavy wear during grading, and needs to be inspected carefully. Pay attention to the teeth on the circle. Even very slight wear will affect the quality of fine grading work and can be very expensive to put right.
Get a colleague to move the circle through its full range of motion, and watch for excessive play on the circle turn cranks and linkages. Also, look for evidence of cracks and re-welds.
If possible, jack the front of the machine up so that the wheels are about 15cm in the air. They should spin freely and there should be no extra play in the radius arms. You can check the axle pivot point by pushing down hard on one of the wheels. It shouldn’t bounce around when it returns.
Finally, with the engine running, press the clutch pedal and turn the steering from side to side. If you feel a kick through the pedal as you do this, it’s a sure sign that the cushion valve is on its way out and will soon need to be replaced.
