Identifying a hydraulic cylinder is crucial for proper maintenance, repair, or replacement.

This blog post will guide you through two reliable methods: decoding the part number and taking accurate measurements.

By mastering these techniques, you’ll be equipped to efficiently locate the right cylinder for your application, saving you time and ensuring optimal performance.

hydraulic cylinder part number lookup

Hydraulic cylinder manufacturers often use part numbers that contain important information about the cylinder’s specifications and features. While the exact format varies between manufacturers, there are some common elements that are typically represented in cylinder part numbers.

One of the most important pieces of information included in a part number is the cylinder bore size. This is usually represented by a number that corresponds to the bore diameter in inches or millimeters. For example, a cylinder with a 4″ bore might have “4” or “100” (for 100mm) somewhere in the part number.

The part number may also indicate the cylinder’s stroke length, which is the maximum distance the piston can travel. This is often listed directly after the bore size, such as “4×24″ for a 4″ bore cylinder with a 24” stroke.

Other common information that may be included in a part number includes:

  • Action type (single-acting or double-acting)
  • Rod end style (threaded, clevis, tang, etc.)
  • Mounting style (fixed, pivot, flange, trunnion, etc.)
  • Seal material (nitrile, viton, polyurethane, etc.)
  • Pressure rating
  • Rod diameter
  • Port type and location

The arrangement and meaning of these elements in the part number is usually specific to each manufacturer. For instance, a part number from one major manufacturer might be structured as follows:

2H34x24 FT S 3.0 N

Breaking this down, we can determine:

  • 2H: The cylinder series (in this case, a heavy-duty hydraulic tie-rod cylinder)
  • 34: The bore size in inches (3.25″)
  • x24: The stroke length in inches (24″)
  • FT: The rod end style (female threaded)
  • S: The mounting style code (side-mounted trunnion)
  • 3.0: The rod diameter in inches
  • N: The seal material (nitrile rubber)

Another manufacturer might use a different format, such as:


In this case:

  • CHD2: The cylinder series
  • 4.5: The bore size in inches
  • MF: The mounting style (fixed rear clevis mount)
  • 6: The stroke length in inches

As you can see, the exact structure and codes used in part numbers are not entirely consistent between manufacturers. However, most cylinder part numbers will include at least the bore size, stroke length, and some information about the mounting and end styles.

Referring to the manufacturer’s hydraulic cylinder cross reference documentation or speaking with their technical sales representatives can help clarify what each part of the number represents for that specific company’s products.

Types of Hydraulic Cylinders Identification

By examining the number of hydraulic ports, the presence or absence of retraction mechanisms, and the overall cylinder design, you can easily distinguish between single-acting and double-acting hydraulic cylinders.

Single-Acting Hydraulic Cylinders

  • A single hydraulic port on the cylinder body
  • No hydraulic port on the opposite end of the cylinder
  • Possible presence of a spring or other mechanical means to retract the piston rod

Double-Acting Hydraulic Cylinders:

  • Two hydraulic ports, one at each end of the cylinder body
  • Absence of external springs or mechanical means to retract the piston rod Hoses or pipes connected to both ends of the cylinder

Other factors to consider when identifying hydraulic cylinders include

  • Mounting style (e.g., clevis, trunnion, or pin-eye mounts)
  • Cylinder body construction (e.g., tie-rod, welded, or threaded)
  • Presence of additional features such as cushioning or position sensing

Key Measurements for Specifying a Cylinder

Bore diameter

This is the inside diameter of the cylinder barrel. It determines the force output of the cylinder. Standard bore sizes typically range from 1.5 to 5 inches in 0.5 inch increments, but can be larger.

If the cylinder is disassembled, measure the bore directly.

If assembled, measure the outside barrel diameter and subtract the wall thickness to estimate the bore.

Rod diameter

This is the outside diameter of the cylinder rod that moves in and out. A larger rod increases strength but reduces the effective force area on the rod side. Measure the rod diameter with calipers. Common rod sizes are 0.5 to 2.5 inches depending on the bore.

Stroke length

The stroke is the distance the rod travels from fully retracted to fully extended. Measure from the center of the rod eye or mount to the same point when extended. Standard strokes are in 2 inch increments from 4 to 24 inches, and larger increments above that.

Retracted and extended lengths

Measure the overall length of the cylinder from mount to mount when fully collapsed and fully extended. The difference between these is the stroke. Typical cylinders have a consistent retracted length for a given stroke.

Mounting style and dimensions

Cylinders have a variety of mounting options on the cap end and rod end, such as clevis mounts, cross tube mounts, side lug mounts, etc. Note the mount types and measure key dimensions like mount width, pin hole diameters, and pin-to-pin distances in the retracted position.

Port thread type and size

Hydraulic ports are female threaded holes that accept fittings to connect hoses. Note the thread type, such as NPT, NPTF, SAE, or BSPP. Measure the thread diameter and count threads per inch to determine the size, such as 1/4″-18 NPTF. Tapered thread types like NPT are measured on the third thread.


Where Is the Serial Number on an Old Hydraulic Cylinder

The serial number on an old hydraulic cylinder is typically engraved on the cylinder shell or stamped on a plate attached to the cylinder.

How Do You Identify a Pneumatic Cylinder and Hydraulic Cylinder

To identify a pneumatic cylinder, look for a cylinder that uses compressed air or gas to generate force.

To identify a hydraulic cylinder, look for a cylinder that uses pressurized liquid like oil to generate force.


Identifying a hydraulic cylinder is crucial for maintenance and replacement. Always check for a part number, usually stamped or engraved on the cylinder, and measure dimensions if necessary.

For further guidance or to explore more about hydraulic cylinders, click here to learn more!

Post time: May-10-2024