How to Select an Equivalent Hydraulic Component

In most cases, a failed hydraulic component can be replaced. But “going with something similar” is a poor strategy: a mistake in mounting dimensions or in the specifications costs machine downtime and a second repair. Below is the process we follow ourselves.

Why equivalents are standard practice

Genuine components often have lead times of 8 to 20 weeks. For a machine that is on site, that is not acceptable. That is why the market has long used equivalents: parts of the same size from other manufacturers, or remanufactured units.

The key phrase here is the same size. An equivalent does not have to be “the same brand”; it has to be interchangeable in mounting dimensions and operating parameters.

Step 1. Collect the source data

Before you start looking, you need five things. Without them, any part matching is guesswork.

• Part number from the nameplate, the tag or the catalogue. Even a partially legible number helps.
• A photo of the component — an overall view plus a close-up of the nameplate, with the connections visible.
• Machine type and model — these often show which version was fitted at the factory.
• Operating pressure and flow — at least the nominal values from the machine manual.
• Reason for replacement — wear, failure, an operating error. This affects the choice.

Step 2. Check the mounting dimensions

This is the most common source of errors. Even when the operating parameters match, a component may not fit.

What to check	Why it matters
Mounting cavity (for cartridge valves)	Several standards exist, and they are not interchangeable. The cavity defines everything else.
Shaft diameter and type	Splined, keyed or tapered — plus the number of splines and the length.
Connection dimensions	Flanges, threads, metric or BSPP.
Port layout	Side, end or angled — this affects hose routing.
Overall dimensions and mounting	Especially for travel and swing motors.

Step 3. Compare the operating parameters

The rule here is simple: an equivalent’s ratings must be no lower than the original’s — not “roughly the same”.

• Nominal pressure — no lower than that of the original component.
• Peak pressure — with headroom, especially if the system sees pressure surges.
• Flow — the working range, not just the maximum.
• Rotational speed — for pumps and motors, both limits matter.
• Fluid type and temperature range — mineral oil, HLP/HM, viscosity.

Step 4. Check compatibility with the system

A component can be in good condition and fit dimensionally, yet still conflict with the rest of the hydraulics.

• Control method — mechanical, hydraulic, proportional or solenoid.
• Settings — if the system has a pressure relief valve, the equivalent’s settings must be matched to it.
• Fluid cleanliness — some components require finer filtration. If the filter is coarser, service life drops.
• Electrics — for proportional valves, the signal type and coil data matter.

Step 5. First start-up and running-in

Even a correctly matched component has to be brought into service carefully.

1. Flush the circuit or replace the filter before installation.
2. Check that there is no air in the system — bleed it.
3. First start-up at reduced pressure, monitoring temperature and noise.
4. After 10–20 operating hours, check the connections for leaks and retighten if necessary.

What we recommend to customers

If a component sits on a machine that works seasonally and downtime is expensive, keep one set of wear seals in stock. The cost of a seal kit does not compare with the cost of downtime.

If the item is unusual and the genuine part has a long lead time, it is worth discussing both options up front: an equivalent from stock and a genuine part to order. We usually offer both and show the difference in price and lead time, so that the customer makes the decision, not the supplier.