Short answer
To measure a hydraulic cylinder for replacement, record seven things: bore (barrel inside diameter), rod diameter, stroke, retracted pin-to-pin length, mounting style at each end, port type and size, and the working pressure. With those seven numbers plus a photo of the nameplate, a builder can reproduce or improve the cylinder even if the original part number is long gone.
What measurements do you need to replace a hydraulic cylinder?
Seven measurements define a replacement cylinder: bore (the inside diameter of the barrel), rod diameter, stroke (how far the rod travels), retracted length measured pin-to-pin or face-to-face, the mounting style at each end, the port type and thread size, and the maximum working pressure of the system. Get those seven right and the geometry, force, and fit are all locked in.
The bore and rod set the push and pull force; the stroke and retracted length set how the cylinder fits the machine; the mounts and ports set how it connects. A photo of the nameplate helps too, but nameplates fall off and part numbers go obsolete, so the measurements are what actually matter.
How do you measure cylinder bore and rod diameter?
Bore is the inside diameter of the barrel, not the outside. The most reliable way to get it without tearing the cylinder down is to measure the rod, then look up the standard bore that pairs with it, but if the cylinder is apart, caliper the barrel ID directly. Bore usually lands on a round figure — common sizes run from 1 inch up through 36 inches.
Rod diameter is easy: put a caliper across the chrome rod where it is clean and unscored. Measure in two places ninety degrees apart to catch any wear or bend. Rod sizes also tend to fall on standard fractions, so if you read 1.98 inches, the rod is almost certainly a 2-inch rod that has seen some wear.
How do you measure stroke and retracted length?
Stroke is the difference between the fully extended and fully retracted length — the distance the rod actually travels. If you can cycle the cylinder, measure the exposed rod fully extended, then fully retracted, and subtract. If you cannot cycle it, measure the extended and retracted pin-to-pin lengths and subtract those.
Retracted length is the collapsed dimension: on a pin-mounted cylinder, measure center-to-center between the two mounting pin holes with the rod fully in. On a flange or threaded mount, measure the equivalent face-to-face closed length. This is the number that decides whether the replacement physically fits the machine, so take it carefully. WestCraft builds strokes up to 360 inches, so long-travel telescoping and single-stage cylinders are both in range.
How do you identify the mounts and ports?
Note the mounting style at each end — clevis (a single pin eye), cross-tube (a tube through the cap), trunnion (pivot pins on the barrel), or flange (a bolt-up plate). Measure the pin bore diameter and the mounting width so the replacement drops onto the same pins and brackets.
For ports, identify the thread type (SAE straight-thread O-ring boss or NPT are the common two) and the size. The safest way to confirm a port thread is to compare the fitting that came out of it against a thread gauge rather than guessing from the hole.
What if you cannot read the nameplate or find the part number?
That is the normal case on older equipment, and it is not a problem. A cylinder is fully described by its measurements, so a builder can reverse-engineer a replacement from the seven dimensions above without ever knowing the original manufacturer or part number. Reverse engineering obsolete and unbranded cylinders is routine custom-cylinder work.
If the rod is bent, the barrel is scored, or a seal surface is damaged, measure the undamaged reference features and let the shop advise on what can be reused versus remade. A written teardown quote tells you exactly what the rebuild involves before any money is spent.