A pin is defined by its outside diameter, its length, its head or thrust arrangement, its grease groove pattern, and how it is retained in the bore. A bushing is defined by its outside diameter, inside diameter, length, and thrust face. Two pins of the same diameter but different length, or two bushings that differ only in thrust width, will fit badly and wear fast. Identification is a matter of five or six measurements taken from the worn part or the clean bore, not of matching a picture on a screen.
What each measurement decides
| Measurement | What it decides |
|---|---|
| Pin outside diameter | The fit in the bushing and the joint. Worn pins are undersize and must be measured at the unworn land. |
| Pin length and head arrangement | Whether the pin seats and retains correctly in that exact joint. |
| Grease groove pattern | Whether grease reaches the working surface. Different joints run different patterns. |
| Retention method | Bolt, plate, O-ring groove or tapped end. Wrong retention walks out of the bore. |
| Bushing OD, ID and length | Press fit in the bore and running clearance on the pin. |
| Thrust face width | Axial location. A narrow thrust face lets the assembly walk and eat the retainer. |
Parts you may need, by grade
| Part | Grades commonly quoted |
|---|---|
| Cylinder pins | Genuine; OEM-quality. Match diameter, length, grooves and retention to the joint. |
| Bushings | Genuine; OEM-quality. Pressed pair with the pin; thrust width matched to the linkage. |
| Retainer bolts and plates | Genuine; OEM-quality. Reused retainer bolts stretch and the pin walks. |
| Seals and O-rings for retained pins | Genuine; OEM-quality. The groove O-ring is what keeps the grease in and the grit out. |
Need the parts this covers?
Send the machine model, serial number and the part numbers you need. We confirm fitment before payment and state the grade of every line — genuine, OEM-quality or aftermarket.
Request a quoteFrequently asked
Can I measure a worn pin and order from that?
Not from the working surface, because wear has already taken the diameter below its catalog value and the result matches nothing. Measure the unworn land under the head or beside the groove, or better, measure the bushing bore and derive the required pin from the fit specification. When in doubt, send both the pin and the bushing dimensions plus the machine model and serial number, and let the supplier match the joint.
Why replace the bushing if only the pin is worn?
Because the pair wears into each other's shape. A new pin running in a bushing that is oval and oversize will polish itself to the same worn profile in a fraction of the normal life, and the joint play returns within months. Pins and bushings are matched assemblies and are replaced together, with the bore checked for ovality before the new bushing is pressed in.
Does it matter where the grease groove is on the pin?
Yes. The groove feeds grease from the entry point around the working surface, and the pattern is matched to how the joint loads and moves. A pin with the wrong pattern fits, runs, and then wears early because parts of the bushing never see grease. It is one of the quiet reasons a supposedly identical part underperforms, and it is why the groove pattern is part of the identification, not an afterthought.