Accurate measurements are essential when replacing an excavator bucket pin. Two pins may share the same basic diameter and length while using different shoulders, retaining systems, grease passages, or usable lengths. Ordering by machine brand alone can also lead to fitment problems because excavators within the same model family may use different pins depending on serial number, attachment type, and pin location.
Before ordering a replacement, remove and measure the original pin whenever possible. Also record the machine model, serial number, original part number, and the exact joint where the pin is installed.
1. Measure the Pin Diameter
Measure across the widest round section of the pin using a caliper or micrometer. The diameter is commonly listed in millimeters, such as 80 mm, 90 mm, or 100 mm.
Measure the pin in several places because a worn pin may no longer be perfectly round. Heavy wear can create flat spots or reduce the measured diameter. When possible, measure an unworn section near the end of the pin.
2. Measure the Overall Length
Overall length is the complete end-to-end measurement of the pin. For example, a pin described as 100 mm x 750 mm normally has a 100 mm diameter and an overall length of approximately 750 mm.
Do not assume overall length and usable length are the same. A head, shoulder, retaining plate, threaded end, or drilled section may reduce the portion that actually passes through the joint.
3. Measure the Usable Length
Usable length is the section of the pin that passes through the bucket ears, linkage, stick, boom, or bushings. Measure between shoulders, heads, retaining surfaces, or other features that stop the pin from moving farther through the assembly.
A pin can have the correct overall length but still be unusable if the effective working section is too short or too long.
4. Record the Pin End Style
Excavator pins can use several end configurations, including:
- Plain round ends
- Flanged or headed ends
- Threaded ends
- Cross-drilled retaining holes
- Bolt-on keeper plates
- Snap-ring grooves
- Welded retaining tabs
The replacement pin must use a compatible retention method. A pin with the correct diameter and length may still not fit if the keeper or retaining-hole location is different.
5. Check for Grease Holes and Internal Passages
Some bucket pins are solid, while others contain internal grease passages that distribute lubricant to the bushings. Record the number and location of grease holes, grease fittings, and internal channels.
Replacing a lubricated pin with a solid pin may prevent grease from reaching the joint properly.
6. Identify the Exact Pin Location
An excavator can use multiple pins with similar dimensions. Identify whether the pin connects the:
- Bucket to the linkage
- Bucket to the stick
- Linkage to the stick
- Boom to the stick
- Boom to the machine frame
- Hydraulic cylinder to the linkage
- Quick coupler to an attachment
Pin location matters because the same machine may use several pins with different dimensions and retaining systems.
7. Check the Bushings and Pin Bores
Before installing a new pin, inspect the bushings and pin bores for excessive wear. A new pin installed into worn, oval, or damaged bushings may remain loose and wear out quickly.
Signs of bushing or bore wear include:
- Side-to-side bucket movement
- Clunking during operation
- Uneven wear on the old pin
- Visible gaps around the pin
- Oval-shaped bores
Excavator Bucket Pin Measurement Checklist
- Pin diameter
- Overall length
- Usable length
- Shoulder dimensions
- Head or flange dimensions
- Retaining-hole location
- Keeper or retainer style
- Grease-hole location
- Pin location on the machine
- Original part number
- Machine model and serial number
Confirm Fitment Before Ordering
Northline Parts carries aftermarket excavator bucket pins for selected CAT, Caterpillar, John Deere, Komatsu, and other heavy-equipment applications. A listed size such as 100 mm x 750 mm is an important starting point, but it does not confirm fitment by itself.
Compare the complete physical configuration of the original pin and verify the machine model, serial number, pin location, and original part number before purchase.