Excavator Hydraulic Pressure in India: Bar, MPa and Pump Flow by Class

Indian excavators run their main digging circuit between 147 and 380 bar, which is the same thing as 14.7 to 38 MPa. Their main pumps push 40 to 8,000 litres of oil a minute. Of those two numbers, flow is the one that grows with machine size. Pressure barely moves.

That surprises most first-time buyers, and it is worth getting straight before you compare two machines. A 21-tonne excavator and a 74-tonne excavator work at almost the same pressure. The big one is big because it moves far more oil, and because its cylinders are fatter.

Three words used throughout this page. Pressure is how hard the oil pushes, measured in bar or MPa. Flow is how much oil the pump sends, measured in litres per minute (L/min). A circuit is one loop of that oil: tank, pump, control valve, cylinder or motor, and back to tank.

Every excavator hydraulic pressure figure below comes from the published specifications of the 294 excavators listed on DesiMachines. Of those, 288 publish a pump flow figure and 287 publish a working-circuit pressure, so this is a reading of the actual catalogue rather than a general rule copied from a textbook.

What do MPa, bar and kg/cm² mean on a spec sheet?

They are three ways of writing the same thing, and Indian spec sheets use all three.

MPa stands for megapascal and is what most excavator spec sheets print. Bar is the unit most mechanics and hose shops actually speak in. kg/cm² is the older unit you still hear around older machines and in smaller workshops. The conversions are easy enough to do in your head:

So a spec sheet printing 34.3 MPa and a mechanic saying “three fifty” are describing the same machine. If a figure looks ten times too small or too large, check which unit it is written in before you decide the machine is weak.

One number is worth committing to memory: 350 bar. That is roughly where the whole industry has settled for the main working circuit on a full-size machine, and the reason is in the section after next.

How much hydraulic pressure and flow does each size of excavator run?

Here is the whole listed range, grouped by the size class each machine is sold in. The pressure column is the implement circuit, meaning the circuit that drives the boom, arm and bucket. That is the one doing your digging.

Specifications as per the current Sep 2026 listings. These five classes hold 268 of the 294 machines. The rest carry a different tag rather than a weight tag: 12 are long reach machines, 13 are electric, and one is a wheeled excavator. Those are a second way of sorting the same catalogue, so they are not a sixth row.

Read the two middle columns against each other and the pattern is hard to miss. Flow climbs from 77 to 1,024 litres a minute, about thirteen times over. Pressure climbs from 230 to 343 bar and then stops. Medium and Large machines sit at exactly the same 343 bar median, and the biggest class reads slightly lower at 320 bar.

Meanwhile the machines themselves go from 1,800 kg to 825,000 kg. That is a 458-fold jump in weight against a 1.5-fold jump in pressure.

Why doesn’t a bigger excavator run higher pressure?

Because pressure is limited by what the parts can hold, and force is bought a different way.

The push a cylinder produces is its oil pressure multiplied by the area of its piston. A designer who wants twice the digging force has two options. Double the pressure, which means every hose, seal, pump, valve and cylinder wall on the machine has to be built to hold it. Or fit a fatter cylinder, which costs steel and nothing else. The second option is cheaper and safer, so that is the one the industry takes.

Speed works the same way. A fatter cylinder needs more oil to fill it, and a bigger machine has a longer boom to move. Both are paid for in litres per minute, not in bar. The pump gets bigger and the pressure stays where it was.

This is why a 350 bar reading tells you very little on its own. The JCB NXT 150 at 14,700 kg runs 330 bar. The CAT 374 at 74,000 kg runs 370 bar. The CAT is five times the machine on a pressure figure only 12 per cent higher, and the real difference sits in the flow: 240 L/min against 896 L/min.

One caution on the biggest class. Its 320 bar median is genuinely lower than the Medium and Large classes above it, but that group mixes 51-tonne site machines with 800-tonne mining shovels built to a different brief, so it reads better as a mixed group than as a trend. Very few Indian contractors will ever buy one. If your work is in that range, compare the mining-class excavators individually rather than by class average.

What are the four hydraulic circuits on an excavator?

Your machine does not have one hydraulic pressure. It has four, and they are deliberately different.

The four circuits and what each one runs at

The swing circuit sits lower on almost every machine, and that is deliberate. Turning the upper body is lighter work than dragging 22 tonnes uphill, and a softer swing circuit is what stops the machine snapping round and throwing a full bucket.

The pilot circuit is the one worth understanding properly. At 39 bar it runs at roughly one-ninth of the digging pressure. Your joysticks do not push oil to the boom. They send a small, gentle signal that tells the main control valve how far to open. That is why a heavy machine can be steered with two fingers, and it is also why a fault in one cheap pilot line can make a perfectly healthy 400-litre pump feel dead. The motors on the other end of the travel and swing circuits are covered in the guide to excavator swing and travel motors.

What does pump flow actually buy you on site?

Speed. Flow is cycle time, and cycle time is how many trucks you load before lunch.

Two machines at the same 343 bar will dig with similar force. The one with the bigger pump completes the dig, swing, dump and return faster, because every cylinder on it fills quicker. Over a shift that difference is trips, not seconds. Working out what it means for your own site is covered in how to calculate excavator productivity.

Flow also decides what attachments a machine can run, and this is where buyers get caught. A hydraulic rock breaker is sized to a flow window, not to a machine weight. Give a breaker less oil than it asks for and it hits softly and slowly. Give it a great deal more and you heat the oil and beat up the tool. This is the most common reason a breaker underperforms on a machine that is otherwise the right size.

So when you compare two machines in the same weight class, ask for the pump flow figure, not just the pressure. In the 15–25 tonne class the listed flow runs from 315 to 520 L/min, a 65 per cent spread inside one size class. Pressure across that same class only spans 279 to 373 bar.

Named machines, for reference

Specifications as per the current Sep 2026 listings. Where a machine does not publish a circuit figure, this table says so rather than borrowing one from a similar model.

Compare excavator models and prices across every size class, and speak to a dealer about which pump flow suits the attachments you plan to run.

How do you know when hydraulic pressure has dropped?

The machine gets weak before it gets noisy, and it usually gets weak in one circuit first.

Lost pressure on the implement circuit shows up as a bucket that stalls in hard soil while the engine holds its revs. Lost pressure on the swing circuit shows up as a machine that will not turn uphill with a full bucket. Lost travel pressure shows as one track crawling while the other pulls, so the machine tracks in a curve. A pilot circuit fault is different: the machine feels lazy or dead everywhere at once, even though the main pump is fine.

Two causes come before any pump diagnosis, and both are cheap. Hot oil loses pressure because thin oil slips past internal clearances, covered in excavator hydraulic oil temperature. A choked filter starves the pump, and the intervals are in the guide to excavator filters. Only after ruling both out is it worth reading what a hydraulic pump repair costs.

Actual pressure testing is a workshop job. The gauge has to go on the correct test port for the circuit being checked, with the engine at the rated rpm named in the machine’s manual, and a reading taken at the wrong rpm means nothing.

One safety warning belongs here. At 343 bar, oil escaping a pinhole in a hose comes out as a jet you cannot see, and it will pass through skin. A puncture that looks minor is a surgical emergency rather than a wound to wash and wrap, and hospitals treat it as one, as the medical summary of high-pressure injection injury explains. Never run a hand down a hose to find a leak. Use a piece of cardboard held at arm’s length, with someone else on the controls. Hose ratings and markings are in the guide to excavator hydraulic hose sizes and fittings, and the oil-and-filter routine that prevents most of this sits in hydraulic system maintenance.

What should a buyer actually check?

Ask for three numbers and you will have compared the hydraulics properly.

Ask for the implement circuit pressure, because that sets your digging force per square centimetre of piston. Ask for the main pump flow in L/min, because that is your cycle speed and your attachment compatibility. Ask for the pilot pressure if you are buying used, where a weak pilot circuit is a common fault and an easily hidden one.

Then read those against weight and reach rather than on their own. A machine at 343 bar with 315 L/min and a machine at 343 bar with 520 L/min sell in the same size class and will not do the same day’s work. Digging force figures are published separately and are worth reading beside this page, in excavator bucket and arm digging force. How the classes are defined in the first place is set out in excavator size classes in India, machine weights in excavator weight by class, and engine output in excavator engine power by size class. At the small end, the mini excavator guide covers the 0–6 tonne machines in full.

For a first machine the practical advice is short. Do not pay extra for a pressure figure. Two machines in the same class sit within a few per cent of each other, and marketing that leans on a bar number is selling you something every competitor also has. Pay attention to flow, to the attachments you intend to run, and to whether a dealer near you stocks pump and valve parts.

Browse the full range of excavators in India by size class, from mini and small machines through the 15–25 tonne and 25–50 tonne classes, and ask a dealer for the pump flow figure before you sign.

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.