How to Identify a Faulty Hydraulic Pump Before It Wrecks Your Machine

RALPH COPE
May 6
5 min read

Don't wait until your excavator sounds like a dying walrus.

Let’s get one thing straight: your excavator’s hydraulic pump isn’t just a part—it’s the part. It’s the heart of the machine. Without it, your boom’s just a big, lazy arm and your bucket’s just a glorified cup. So when that hydraulic pump starts going dodgy, it doesn’t just slow you down—it threatens to turn your million-rand machine into a very expensive paperweight.

The good news? Hydraulic pumps don’t fail out of nowhere. They give you signs—grunts, groans, leaks, stutters—all the mechanical equivalents of a guy trying to say, “I’m not feeling too lekker, mate.”

This guide is your no-BS, grease-under-the-nails breakdown of how to spot a faulty hydraulic pump before it nukes your machine (and your bank account). Plus, we’ll tell you what to do about it—because we’re not just here to scare you.

First, What Does the Hydraulic Pump Actually Do?

Before we get into the signs of failure, let’s quickly clear something up.

Your excavator’s hydraulic pump is what powers everything—boom, arm, bucket, swing, travel—you name it. It draws hydraulic fluid from the reservoir and pressurises it to make things move. It’s basically the heartbeat of the hydraulic system.

So when it starts failing? You’re not just losing performance. You’re risking:

Massive downtime
Hydraulic system contamination
Blown hoses and valves
Seized motors
Wallet-crushing repairs

The 9 Signs Your Hydraulic Pump Is in Trouble (Pay Attention, Bru)

Let’s dig into the dirty signs your pump is crying out for help.

1. Strange Noises (Growls, Whines, or Screeches)

Your excavator shouldn’t sound like a dying animal. If the pump starts making high-pitched whining, loud screeching, or weird growling noises, it could mean:

Cavitation (air in the hydraulic fluid)
Damaged bearings or gears
Oil starvation

Translation: Bad juju. Shut it down and inspect it.

2. Loss of Power or Slow Movements

If your boom lifts like it's had one too many Castle Lagers the night before, something’s off. A failing pump can’t maintain the proper pressure, leading to sluggish or jerky movements.

Pay attention if:

Your bucket struggles to curl
You lose lifting power
Travel motors are weak

This isn’t just annoying—it’s dangerous.

3. Overheating

Hydraulic fluid getting hotter than it should? That could mean the pump is inefficient or internally damaged.

Symptoms include:

Scorching hot fluid or pump housing
Overheat alarms on your panel
System pressure drops

Pro tip: Check fluid temps with a thermal gun. Anything consistently above 80°C = bad news.

4. Leaking Hydraulic Fluid

Oil puddles under your machine are never a good sign. If it’s coming from the pump area, you could be dealing with:

Worn seals
Cracked housing
Loose fittings

And don’t think you can “top it up and keep going.” Leaks = contamination = eventual system death.

5. Inconsistent Pressure Readings

Hooked up a gauge and the readings are jumping like a springbok? Or worse—dead flat?

That’s your pump saying, “I’m done.” Pressure spikes, drops, or total loss = pump failure or bypassing happening internally.

6. Hydraulic Fluid Looks Dodgy

Pull the dipstick or check your sight glass. If your hydraulic oil is:

Milky (water contamination)
Dark brown/black (burnt oil)
Full of metal flakes (kill me now)

…you’re already halfway down the path to pump destruction.

7. Sudden Jerky Movements

A faulty pump will fail to deliver consistent pressure. That means jerky, unpredictable movements, like your machine's been hitting the Red Bull.

Could be a worn swash plate, broken internal components, or aerated fluid.

8. Excessive Vibration

Your pump should hum along, not shake like it's in a mosh pit. If it’s vibrating excessively, you might have:

Misaligned couplings
Worn bearings
Loose mountings

Vibration is more than annoying—it causes further wear across the system.

9. Alarms and Fault Codes

Modern excavators often throw fault codes related to:

Low system pressure
High temps
Poor flow rates

Don’t ignore these. They’re not just there to annoy you—they’re warning signs. Read the manual, or better yet, call us.

How NOT to Diagnose a Hydraulic Pump

Let’s clear up some common bush-mechanic myths.

“If it still moves, it’s fine.” Nope. Early-stage failure still causes damage elsewhere.
“Just change the filter and top up the oil.” That’s like putting a plaster on a gunshot wound.
“Ignore the leak, it’ll go away.” No, it’ll invite contamination and kill your whole system.

You can’t guess with hydraulics. You diagnose, pressure test, and confirm.

How to Properly Test a Suspect Hydraulic Pump

Here’s what the pros do (and what we do at Vikfin):

✅ Flow Testing

Measure how much fluid the pump is actually moving at full pressure. Low flow = worn pump.

✅ Pressure Testing

Attach a gauge and test output pressure at different RPMs. Fluctuating or low pressure is a bad sign.

✅ Case Drain Testing

Measures internal leakage from the pump back to the tank. High case drain flow = internal wear.

✅ Visual Inspection

Look for signs of wear, cracks, seal failures, or shaft play.

What Happens if You Ignore It?

Here’s what could go wrong if you don’t fix a faulty pump:

Catastrophic failure—shards of metal fly into your entire hydraulic system
Blown final drives or swing motors—from pressure spikes or dirty oil
Downtime that costs you contracts
A mechanic bill that makes you cry

Not worth it.

What to Do if You Suspect a Faulty Pump

Here’s your playbook:

Shut down the machine
Don’t keep running it “just to finish the job”
Call someone who knows what they’re doing (Hint: that’s us)
Have it tested properly
Replace or rebuild with a quality-tested pump

At Vikfin, we can test, supply, or rebuild your hydraulic pump—fast. We keep rebuilt and new aftermarket units on hand, already flow-tested and ready to go.

Should You Rebuild or Replace?

It depends on the damage. Here’s the rough guide:

✅ Rebuild if:

No major cracks or housing damage
Rotating group is still usable
You want to save cash

❌ Replace if:

Catastrophic failure with contamination
Pump is obsolete
Repair costs exceed 70% of replacement cost

We’ll give you an honest answer. If a rebuild won’t last, we’ll tell you. No fluff, no sales pitch.

Why South Africans Trust Vikfin for Hydraulic Pumps

We don’t just move boxes—we understand machines. Here’s what sets us apart:

All pumps are tested before leaving
We keep stock on hand
You get expert advice, not call centre drivel
We stand behind our parts with warranties
We actually give a damn about your uptime

We’ve helped everyone from solo operators to big construction fleets. If your pump’s shot, we’ll get you running again—no guesswork, no nonsense.

Wrap Up: Don’t Let a Pump Wreck Your Whole System

Hydraulic pumps rarely fail without warning. The trick is catching the signs early—and taking them seriously.If something feels off, check it. Because ignoring a dodgy pump is like ignoring chest pain on the job site: it’s not brave, it’s dumb.

If in doubt, call Vikfin. We’ll test it, replace it, or rebuild it—whatever gets you back in the dirt fastest and safest.

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Need a pump tested? Got a weird sound coming from your machine? Want to WhatsApp us a video with the caption “WTF is this noise?” Go for it.

Vikfin’s got your back. No fluff. Just parts that work—and advice that matters.