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Hydraulics Doctor

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Do you have a problem to do with hydraulics?

Contact our Hydraulics Doctor for prompt, free, no-obligation advice.

This page also answers the questions we are most frequently asked about hydraulics. At Armada, we’re more than happy to offer the benefit of our expertise.

From superyacht systems to military defence installations and large-scale shipping contracts, Armada exists to help its clients achieve trouble-free hydraulic systems that go on working reliably. We also provide consultancy and training in the operation of hydraulic systems

How often do I need to renew the oil within my hydraulic system?

This is dependent on the oil temperature, the application, work cycle and level of filtration installed within the hydraulic circuit. To discuss in further detail, please contact our specialist team.

Why do my hydraulic hoses keep bursting?

The most common reasons for hose bursts is the wrong application, corrosion of the ferrules, high pressure pulsing of the hydraulic installation, incorrect bend radius of the installed hose and out of date hoses.

For more assistance and to discuss your hose requirements please contact us.

How hot should my hydraulic system be getting?

The temperature of a hydraulic system relates to the oil that is used within the system. Most hydraulic systems use mineral based hydraulic oil. Dependent on its centistokes viscosity, you can determine how hot the hydraulic system should be getting from the oil manufacturers data sheet. As a guideline, you have to consider the ambient temperature and the work cycle of your hydraulic system and the original designer’s allowance for heat transference. General figures for a temperate climate (Northern Europe) use 32 grade oil. For higher ambient temperatures use 46 grade oil to give more stability under these conditions.

What’s the best way of collecting spilt hydraulic oil?

Whenever breaking into any hydraulic system, you must first consider these safety measures:

  1. Is the system live?
  2. Does the system have an inherent pressure i.e. accumulators or systems underload
  3. Also consider gravity

Isolate, if possible, using ball valves or steel caps. If oil has been spilt, you can use granules, filter pads and boom pads. To ensure you have these on hand, visit or call our sales team on 01326 375566.

How often should I change my hydraulic filters?

You must always refer to the original manufacturer’s official information. However most hydraulic systems will have a return filter that either has a visual clogged indicator or an electrical clogging indicator for your observation.

What grade of hydraulic oil should I use?

You should firstly consult your operators’ manual for their recommendations. As a guide, small yacht steering systems would use 15 grade mineral based oil. Hydraulic systems in temperate conditions (northern hemisphere) use 32 grade. In tropical conditions, use 46 grade oil. There are occasions where flame retardant oil would be required. In these cases a synthetic oil should be used. Caution is required with these oils as they are toxic. When using any hydraulic oil or lubricant, you must observe COSH information.

Is hydraulic oil safe for my skin?

As with all oils, protective clothing should be worn and COSH information will be available from the oil supplier.

To purchase protective clothing, visit or call our sales team on 01326 375566.

What are the advantages of stainless steel fittings over steel plated?

Stainless steel fittings and couplings are widely used in marine & chemical environments. The corrosion resistance of stainless steel offers great advantages for the future removal and is aesthetically pleasing. However, when installing stainless steel components, care must be taken to ensure a suitable anti-gawling paste, as stainless steel will lock up the coupling and cause the user problems.

Steel plated fittings offer minimal corrosion resistance and therefore, when used within the marine industry, rust and cause the end user problems when dismantling. Steel plated fittings have cost advantages and used in a non-marine environment are both cost effective and practical.

Where can I get hydraulic fittings/parts?

All your hydraulic component needs are catered for at where we offer over 70,000 products combined with next day delivery. If you prefer, or need assistance with your order, you can contact our expert sales team on 01326 375566

What is the difference between 2 wire & 4 wire hydraulic hoses?

Marked on all hydraulic hoses is the following information:

  • Date of manufacture
  • Manufacturer’s name
  • Working pressures
  • DIN specification

In brief, the wire reinforcement integrated in the hose assembly denotes its strength relative to working pressure. The more wire reinforcement, the higher the pressure relative to the bore of the hose.

For example

SAE100R2AT 2 wire 4SP Multispiral 4 wire
3/8” bore 330 bar wp 3/8” bore 460 bar wp
1⁄2” bore SAE100R2AT 275 bar wp 1⁄2” bore 440 bar wp
3⁄4” bore SAE100R2AT 215 bar wp 3⁄4” bore 380 bar wp
1” bore SAE100R2AT 165 bar wp 1” bore 320 bar wp
1 1/4” bore SAE100R2AT 125 bar wp 1 1/4” bore 240 bar wp

Please note when selecting a hose, care must be taken as hydraulic systems can vary with the pulsing and spikes generated within the system. Professional advice should be sought.

Please contact us regarding the selection of hoses as this is only a small sample of the products available to satisfy your requirements.

Can hydraulic hoses be fireproof?

Yes. However, fireproofing of hoses is a complicated matter. We offer a range of MSHA approved hoses which are flame resistant to US MSHA Approval IC-188. To cover the hydraulic range, please contact us for the full range and related data sheets.

How can I test my hydraulic system for faults?

The basic components to any hydraulic system are as follows:

  1. The prime mover (engine, electric motor etc)
  2. Hydraulic pump pressure & flow
  3. Control gear
  4. Relief valve system pressure
  5. Motor or cylinder etc

With any fault finding, if you break the system down into manageable areas as above, you can identify the location of the fault. To progress further, please contact us to discuss your exact requirements and we will advise the best way to proceed.

Why are there different pump and motor designs in the market place?

Basically, the pumps and motors available in the marketplace relate to a number of design factors:

  • Working pressures
  • Applications
  • Selection of hydraulic fluid
  • Noise level
  • Available horse power
  • Flexibility i.e. hydraulic pressure & flow control which includes electrical control.
  • Cost

We offer a design and consultancy facility which offers full computer aided design. Contact us for further information.

When starting a system from new or repair, what precautions do I need to take?

Firstly, you must consult the originator’s equipment manual for starting procedures. However, we do not recommend any person without knowledge to start a system, as damage to the equipment, yourself and others may result. If you would like advice, we would be pleased to help. Just give us a call.


The Hydraulics Doctor is designed to offer guideline advice for people within the industry. It is not designed to provide comprehensive advice and we would always recommend contacting us to discuss your requirements before proceeding.

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