Hydraulic leaks can have both direct and indirect costs. In this article, we address the main consequences to be aware of, how to diagnose a hydraulic fluid leak, and strategies you can adopt to avoid them.
Why Do Hydraulic Systems Leak?
Wear-and-tear created by accidental hydraulic aeration (i.e. unexpected exterior air intake causing internal fluid ‘cavities’) is the root of most hydraulic leaks. Air bubbles inside caveated oil cause rapid pressure and heat changes due to intense, unbalanced kinetic motion. Wasted energy is transferred differentially into kinetic impact force, creating microscopic fissures in the fluid reservoir, allowing liquid to escape.
Aeration isn’t the only breach risk that could affect your hydraulics. Other causes of leaks include:
- Chamber flooding
- Component collisions
- Corrosion, melting, and rust
- Dust, fluid, and detritus ingress
- Erratic pump performance
- Human error (e.g. Collisions, drops, impacts, scrapes)
- Faulty, badly fitting, under-tightened, overtightened, or misaligned connectors (e.g. O-rings)
- Internal operating temperatures exceeding 82 °c
- Motor, piston, and ram failure
- Natural ageing – no component lasts forever!
- Jams and clogs
- Seam misalignment
- System overpressurisation
What Are The Costs?
Hydraulic leaks in a major system are often environmentally and financially damaging. You may suffer from:
- Excess oil bleed – Microleaks slowly drain the system’s hydraulic oil supply. Reservoir top-ups inflate costs.
- Hydraulic collapse – Sudden cascade depressurisation is often rapid and catastrophic.
- Increased wear-and-tear – Cumulative damage quickly wears out pipes, motors, servos, and gauges.
- Problematic pressure – Aerated, leaking hydraulic fluid is less effective at transferring raw power from pumps.
- Toxic spillover – Escaped oil is a green nightmare – water-soluble, hard-to-contain, and highly poisonous.
How Can I Detect A Hydraulic Leak?
Hydraulic leaks can start microscopic and are often tricky to spot as they develop and worsen. Watch out carefully for these early warning signs:
- Higher than expected internal temperature
- ‘Puddling’ – small pools of hydraulic fluid collecting directly under components.
- ‘Low fluid’ warnings or alarms – check the reservoir and component gauges.
- Machinery failing to start or stop promptly
- Unexpected hissing noise – can indicate rapid fluid expulsion.
- Oil staining and vertical ‘slicks’ – the result of a leaky joint, seal, or join.
- Slow or sub-par operation
- Sudden shifts, stalls, or stutters
- Repetitive ‘banging’ noises – a tell-tale symptom of fluid cavitation.
- Vibrating connectors and fastenings.
If you can detect leaks quickly, small-scale replacements or readjustments will often save you from the cost and downtime of a persistent hydraulic leak.
How Can I Avoid Hydraulic Leaks?
Airtight insulation is the best way to minimise the risk of hydraulic leaks. Sealing your loop, connectors, reservoir, and pump tightly will prevent oil aeration from exceeding a safe 9% baseline. Investing money in quality, protected components, pipelines, seals, and transfer connectors pays for itself.
You can also set up regular maintenance schedules and place alarm sensors to double-check that nothing’s worn thin. Routine calibration, condition, and performance checks are your best safeguard against leaks.
Do not operate, touch, or power on a leaking hydraulic system. If you detect or suspect a leak, halt immediately and isolate the machinery from humans and animals. It is dangerous and counterproductive to continue working with or around broken hydraulic equipment. Contact a trained technician for advice if you’re ever unsure.
Hydraulic Engineering Services From Hydrastar
Hydrastar provide hydraulic design services and catalogue component orders to customers across the UK. Please call 01353 721 704 today to find out more.
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