Hydraulic excavator attachments can fit the mounting bracket and still work poorly when the carrier supplies the wrong flow, return arrangement or control mode. A breaker that slows as the oil warms, a shear that closes reluctantly and a rotating tool that overheats require different checks. Before ordering, the useful question is whether the complete carrier circuit can supply the chosen attachment continuously through the installed hoses and couplings.
Start with the excavator model, auxiliary circuit specification and intended tool. Then compare operating flow, pressure, return restrictions, attachment mass and the functions used together. This guide follows that compatibility check from the machine records to a practical acceptance test. It helps a buyer request a defined installation package rather than discover missing pipework after delivery.
Identify The Circuit Before Choosing The Attachment
A single-direction breaker circuit and a reversible cylinder circuit do different jobs. Breakers generally require the supply and return arrangement specified by their manufacturer. A shear needs controlled opening and closing, while a rotating attachment may require a separate rotation circuit or an approved switching arrangement. Two hoses on the boom do not establish that every function is available.
Ask for the excavator’s auxiliary hydraulic diagram and the actual installed options. Record whether flow is adjustable, which operating mode controls it and whether the return passes through a valve, filter or cooler. A case drain, where the attachment requires one, has a separate purpose and cannot automatically share an ordinary return connection. Have the supplier identify each required connection before comparing prices.
Read Flow And Pressure As A Matched Operating Point
Flow largely governs actuator speed or the available operating cycle, while pressure supports the load the mechanism can overcome. Both must stay within the attachment’s specified operating range. A high excavator pump rating is insufficient evidence because other machine functions, engine speed and control settings affect what reaches the auxiliary outlet.
For a preliminary hydraulic-power calculation, pressure difference in bar multiplied by flow in litres per minute and divided by 600 gives kilowatts. This is hydraulic power before mechanical losses. Use the pressure difference across the attachment, not a relief setting copied from the excavator brochure. The calculation is a comparison tool; it does not authorize increasing pressure or flow beyond either manufacturer’s limits.
Compare values at the same oil temperature and operating condition. The installed circuit may deliver acceptable flow with no load but fall short when resistance rises. Conversely, excess flow can produce heat or operating speeds the attachment cannot tolerate. Request a measured flow-and-pressure result for the intended mode, with the return condition recorded alongside it.
Send the excavator model and auxiliary circuit specification so YG can compare the available operating range with your intended tool.
YG Breaker Parameters As A Matching Example
The following selected rows from the published YG hydraulic breaker machine range show why carrier tonnage alone cannot complete selection. They are model references for breakers, not universal settings for all hydraulic excavator attachments. The pressure unit below retains the source’s kilogram-force per square centimetre convention; confirm the exact equipment specification before commissioning.
| Model | Chisel diameter | Carrier range | Main body mass | Operating pressure, kgf/cm² | Oil flow |
| YG530 | 53 mm | 2.5–4.5 t | 85 kg | 90–120 | 25–50 L/min |
| YG680 | 68 mm | 4–7 t | 152 kg | 110–140 | 40–70 L/min |
| YG850 | 85 mm | 7–14 t | 278 kg | 130–160 | 60–100 L/min |
| YG1350 | 135 mm | 16–26 t | 846 kg | 160–180 | 130–150 L/min |
| YG1750 | 175 mm | 35–40 t | 1,929 kg | 180–200 | 210–290 L/min |
Notice that overlapping carrier ranges do not make models interchangeable. Confirm the complete installed mass, bracket, tool and operating geometry against the excavator’s permitted attachment loading. Main body mass is only one component. A shortlisted model must pass both the mechanical installation check and the hydraulic check before its impact performance is considered.
Return Resistance And Heat During Continuous Work
Return Path Restrictions
Oil must leave the attachment through the approved path. Small fittings, long hoses, partially connected couplers and restrictive valves can raise return pressure. This reduces the usable pressure difference and may affect seals or operation. Ask for the attachment’s permitted back pressure and how it will be measured on the installed machine; do not substitute a generic limit.
Changing only the supply hose may leave the restriction untouched. Review the complete route, including the coupler passage and return valve position. When the tool is rotated or curled, check that hoses do not flatten, rub or tighten. These physical checks are particularly useful when a problem appears only at one boom position.
Heat Under The Intended Duty Cycle
A brief cold test cannot show whether the machine can sustain continuous attachment work. Oil temperature changes viscosity, and throttling or excessive pressure loss adds heat. Cooling condition, ambient temperature and simultaneous boom functions therefore belong in the trial. Cleaning cooler fins may resolve a maintenance issue, but it cannot correct an incorrectly specified circuit.
Have the installer record temperature trends during representative operation and use the manufacturer’s limits. If performance declines as the system warms, investigate the cause before increasing settings. Keeping a comparable test record helps distinguish an attachment problem from inadequate cooling, restrictions or carrier wear.
Share the planned operating hours, return arrangement and measured temperature trend. YG can identify which installation details need confirmation.
Couplings, Brackets And Additional Functions
Hydraulic compatibility must be checked alongside pin diameter, ear spacing, bracket width and quick-hitch geometry. The hydraulic quick hitch determines how the attachment mounts, but its locking circuit does not necessarily supply the working tool. List the hitch, main tool and rotation functions separately so the quotation covers every required connection.
A hydraulic shear also changes the selection question from repeated impact to cylinder force, opening, closing and possible rotation. Confirm the controls available to the operator and which functions can operate together. Document fittings, hose lengths, protective routing and any required valves as part of the supplied scope, rather than leaving them as unspecified site accessories.
Provide bracket measurements and the required working functions so the complete connection package can be checked before shipment.
An Acceptance Test That Can Be Repeated
Begin with installation inspection, correct fluid and manufacturer-approved settings. A qualified technician should verify the auxiliary circuit using suitable measurement equipment. Record carrier identity, tool model, operating mode, oil temperature, flow, pressure and return conditions. Then demonstrate the tool on representative material, using the intended boom positions and normal operating sequence.
Retain both the settings and the observed result. Record cycle behaviour, interruptions, temperature trend and any leakage or abnormal noise. A test that simply shows the attachment moving cannot establish productive operation. Where results differ from the proposal, isolate one variable at a time and repeat the same task so the comparison remains meaningful.
Diagnosing A Mismatch Before Ordering Parts
| Observed problem | Checks to prioritize |
| Tool moves slowly under load | Delivered flow at working pressure; control mode; restriction |
| Performance falls as oil warms | Cooling condition; temperature trend; carrier and circuit condition |
| Trouble occurs at one boom position | Hose routing, bend radius and coupler strain |
| Rotation works but the main tool does not | Separate circuit functions and valve arrangement |
Treat these as starting points for diagnosis, not proof that a particular part has failed. An accurate quotation should identify the chosen attachment, mounting parts, hoses, controls and any carrier modifications. Include the acceptance conditions and responsibility for commissioning, especially when the excavator and attachment come from different suppliers.
Send the completed circuit measurements and mounting details. YG can prepare a model-specific attachment and installation scope.
Hydraulic Attachment Buyer FAQ
Match hydraulic excavator attachments by the complete operating circuit and mounting arrangement. With those facts established, the supplier can identify a compatible model and a clear installation scope, and the site team can verify the result against the same record.
Use the flow available to the auxiliary circuit at the required operating pressure. Total pump capacity may serve several functions and does not establish attachment delivery.
No. It establishes a mounting arrangement. Working flow, pressure, return routing and control functions still need separate checks.
Identify the cause first. Flow, restriction, controls and mechanical load can cause slow operation; settings must remain within approved limits.
Provide excavator model, intended attachment, circuit data, mounting measurements, material and working hours. Include measured results when an existing installation has problems.
