説明
The QY350.59.003 is a 63 mm bore tractor hydraulic lift cylinder with a 35 mm rod, 140 mm stroke, and 300 mm mounting distance. It is the longest-stroke cylinder in the 300 mm mounting subgroup — sharing its bore, rod, and mounting distance with the TEQ300.59.001A (120 mm stroke) and the YC504D.55.501 (100 mm stroke), while providing 40 mm more travel than the shortest and 20 mm more than the mid-stroke model.
For a buyer replacing an existing cylinder, the stroke distinction is the critical decision point. All three cylinders in this subgroup will bolt into the same bracket spacing. The QY350.59.003 will install and retract identically to the other two — but at full extension it reaches 20 mm further than the TEQ300.59.001A and 40 mm further than the YC504D.55.501. Whether the machine was designed for that full 140 mm of travel determines whether this is the correct replacement.
Ever-Power supplies the QY350.59.003 as an aftermarket replacement cylinder for agricultural tractor hydraulic lift systems. Confirm the stroke of your existing cylinder before ordering.
QY350.59.003 — Technical Specifications
| パラメータ | Value | Notes |
|---|---|---|
| Bore Diameter | 63 mm | Same bore as all 63 mm group cylinders in this range |
| Rod Diameter | 35 mm | Shared with YC504D.55.501 and TEQ300.59.001A in the 300 mm subgroup |
| Stroke | 140 mm | Longest stroke in the 300 mm mounting subgroup; 20 mm more than TEQ300.59.001A |
| Mounting Distance | 300 mm | Pin-center to pin-center, fully retracted; shared with YC504D.55.501 and TEQ300.59.001A |
| 応用 | Agricultural tractor hydraulic lift systems | Verify stroke of existing cylinder before ordering |
| Supplier | Ever-Power | OEM and aftermarket supply; custom specifications on inquiry |
The 300 mm Subgroup: Why Stroke Is the Only Remaining Variable
Three cylinders in this product range share a 63 mm bore, 35 mm rod, and 300 mm mounting distance. Because all three dimensions are identical across the subgroup, measuring bore, rod, and mounting distance will not distinguish one from another. The stroke — and only the stroke — separates them.
| Model | Stroke | Extended Length (pin–pin) | Position in subgroup |
|---|---|---|---|
| YC504D.55.501 | 100 mm | 400 mm | Shortest stroke |
| TEQ300.59.001A | 120 mm | 420 mm | Mid stroke |
| QY350.59.003 | 140 mm | 440 mm | Longest stroke |
All three cylinders mount identically — same bracket spacing, same rod-end and base-end pin diameters (assuming rod diameter and end connection geometry are consistent across the subgroup). In the retracted position, they are dimensionally the same installation. The difference only becomes apparent when the lift control is operated: the QY350.59.003 pushes the lift arm 20 mm further than the TEQ300 and 40 mm further than the YC504D, producing a correspondingly greater range of implement position.
What 140 mm of Stroke Actually Does in a Tractor Lift System
Stroke translates directly into available implement travel range, scaled by the mechanical linkage ratio of the specific machine. If the tractor’s lift arm geometry converts cylinder travel into implement vertical movement at roughly a 3:1 ratio — which varies by machine design — then 140 mm of stroke produces approximately 420 mm of implement height change between fully lowered and fully raised positions. A 120 mm stroke cylinder in the same machine would yield roughly 360 mm of vertical travel: 60 mm less range.
That difference in height range matters for some applications more than others. For implements that need to clear significant ground obstacles, or where precise positioning across a wide vertical range is important, the additional 20 mm of stroke translates to measurable operational flexibility. For simpler applications where only a modest lift range is needed, the shorter-stroke cylinder may be perfectly adequate — and fitting the QY350.59.003 into a system designed for 120 mm of travel creates the risk of over-extending the linkage.
Over-travel: what happens when stroke exceeds the linkage design
When a replacement cylinder has more stroke than the original, the lift arm reaches its mechanical end stop while the cylinder is still pressurized and extending. At that point, the system pressure spikes against a dead end — the cylinder continues to push against an arm that cannot move further. Repeated operation in this condition loads the cylinder end caps, the pivot pins, and the lift arm mounting points beyond their designed operating range. The immediate consequence is accelerated wear; the longer-term risk is fatigue damage to the linkage structure. A cylinder with 20 mm of excess stroke does not immediately destroy the machine, but it does mean every full-raise operation ends with the hydraulic system pushing against a mechanical stop rather than the cylinder reaching its own internal limit first.
The correct approach is straightforward: match the replacement stroke to the stroke of the original cylinder. If the machine was designed for 140 mm, the QY350.59.003 is the correct selection within this subgroup. If it was designed for 120 mm, the TEQ300.59.001A is. The mounting distance is the same either way — the brackets do not change. Only the stroke determines which one is right.
63 mm Bore: Force Considerations
At 63 mm bore, piston face area is approximately 3,117 mm² (π × 31.5²). At a reference pressure of 160 bar, the theoretical extension force is in the order of 49.9 kN. This is identical to the other two cylinders in the 300 mm subgroup — bore is shared, so force potential is shared. The QY350.59.003 does not generate more force than the TEQ300.59.001A or the YC504D.55.501 at the same pressure; it simply delivers that force across a greater travel distance.
Engineering Reference Note: Force figures are theoretical, based on bore geometry and a reference pressure. They are not rated specifications for the QY350.59.003. Actual output depends on the hydraulic system’s operating pressure and circuit conditions. No rated pressure has been confirmed by Ever-Power for publication here.
One point worth stating clearly: tractor hitch lifting capacity — the figure published in brochures — is not derivable from cylinder bore and pressure alone. It depends on the geometry of the lift arm, the linkage ratio, where the cylinder acts on the pivot, and other machine-specific design factors. Hydraulic cylinder force is an input to the lifting system. Rated hitch capacity is the output of the complete machine, established through standardized testing. The two figures are related, but they are not the same number.
Selecting Between the Three 300 mm Mounting Cylinders
If your existing cylinder has a 300 mm mounting distance and 63 mm bore, the selection process within this subgroup comes down to one measurement. Measure the stroke of the existing cylinder and match it to the table below.
| If your stroke measures… | The correct model is… |
|---|---|
| 100 mm | YC504D.55.501 |
| 120 mm | TEQ300.59.001A |
| 140 mm | QY350.59.003 |
If the existing cylinder is damaged beyond measurement, the machine’s service documentation is the next best source. If neither is available, the visible rod travel when the lift operates — from the retracted position to the point where the lift arm contacts its end stop — gives an approximation, scaled by the linkage geometry. For any uncertainty about which model to order, include clear photographs and whatever partial measurements are available in the inquiry — that allows a technical assessment before committing to a part.
Rod Diameter: 35 mm at 140 mm Stroke
At 140 mm stroke, the rod is extended 40 mm further than on the YC504D.55.501 (100 mm stroke) at maximum extension. The 35 mm rod diameter provides adequate stiffness for this stroke length in a well-aligned installation. Buckling resistance is not a concern at 140 mm of extension for a 35 mm rod in a normal agricultural lift application — the unsupported rod length at full extension is short relative to the rod diameter, well within standard engineering practice.
Side loading is a more common concern in practice than buckling at this stroke length. If the cylinder mounting is not aligned with the direction of the lift arm travel — if there is an angular offset between the cylinder axis and the direction of push — lateral forces develop on the rod. Over time, these cause uneven seal wear on one side of the rod seal, and in severe cases, rod bending. Misalignment is an installation geometry problem, not a cylinder deficiency, but it is worth checking if the replacement is being fitted into a system with a history of premature rod seal failure.
Measuring the Existing Cylinder for Replacement
The measurement priority for this subgroup is stroke. Everything else — bore, rod, mounting distance — is shared across three models. Stroke alone identifies which one you need.
| Measurement | QY350.59.003 Target | Method |
|---|---|---|
| Stroke ← most critical | 140 mm | Extended pin-pin distance (440 mm) minus retracted (300 mm) |
| Mounting Distance | 300 mm | Pin-center to pin-center, fully retracted |
| Bore | 63 mm | Inside barrel diameter or calculated from OD minus wall |
| Rod Diameter | 35 mm | Calipers on clean rod surface |
| Pin Diameters | To be measured | Both ends independently; may differ |
| End Connection Type | To be confirmed | Clevis, eye, or other; both ends |
| Port Specification | To be confirmed | Thread type and size, number of ports, port location |
Stroke measurement method when cylinder can be extended: With the cylinder safely supported and hydraulic pressure available, extend the rod fully. Measure pin-center to pin-center in the fully extended position (should be 440 mm for QY350.59.003). Retracted pin-center measurement should be 300 mm. Subtract: 440 − 300 = 140 mm stroke. If the cylinder cannot be extended due to damage or seizure, check the machine’s service documentation or contact us with photographs and whatever dimensions are accessible.
Common Lift System Symptoms and Their Likely Sources
Hydraulic lift problems are rarely straightforward cylinder failures. Most symptoms have multiple possible sources, and jumping to cylinder replacement without circuit isolation is a common and expensive mistake. The three most frequently misattributed symptoms:
Implement drifts down under load
The rate of drift matters for diagnosis. Fast, load-dependent drift — where a heavier implement drifts faster than a light one — is consistent with internal cylinder bypass through a worn piston seal. Drift that is slow and consistent regardless of load weight is more characteristic of control valve bypass. Test by capping the cylinder ports: if drift stops, the cylinder is holding and the leak is elsewhere in the circuit.
Cylinder does not reach full extension
Three possible causes: insufficient hydraulic pressure or flow (check pump output and system relief valve), the lift arm reaching a mechanical stop before the cylinder fully extends (check linkage geometry), or a wrong-specification cylinder with less stroke than the original was fitted at some previous service. If this problem appeared suddenly rather than gradually, pressure loss is more likely than a stroke mismatch.
Banging or jolting at full lift
A sharp impact at the top of the lift stroke usually means the cylinder is hitting its internal end stop with full hydraulic pressure still applied — which happens when the control valve does not neutralize quickly enough, or when the lift arm mechanical stop is not limiting travel before the cylinder reaches its internal stop. A correctly sized and installed cylinder in a well-designed system should not end its stroke with a hard impact.
Requesting a Quotation for QY350.59.003
Include the stroke measurement prominently in any inquiry — it is the key differentiator within this subgroup and allows immediate confirmation of the correct model.
- Reference number: QY350.59.003
- Confirmed stroke from measurement: 140 mm
- Confirmed bore (63 mm), rod (35 mm), mounting distance (300 mm)
- Pin diameters at both ends
- End connection type at both ends (clevis, eye, or other)
- Port thread type, size, number of ports, and port location
- Single-acting or double-acting (confirm from port count)
- Order quantity
- Machine model and year, if known
- Working pressure, if known from machine documentation
- Photos of existing cylinder: side view, both ends, port detail, any markings
Frequently Asked Questions — QY350.59.003
Can the QY350.59.003 replace the TEQ300.59.001A (120 mm stroke)?
Not as a direct replacement if the machine was designed for 120 mm of stroke. The QY350.59.003 installs identically — same mounting distance, bore, and rod — but extends 20 mm further at full stroke. On a machine designed for 120 mm, that means the cylinder reaches full extension after the lift arm has already contacted its mechanical end stop. The hydraulic system then holds pressure against a static load rather than through the cylinder’s internal stop — which is how the system is designed to work. Repeated operation in this condition stresses linkage pivot points and end caps. If your existing cylinder has a 120 mm stroke, the TEQ300.59.001A is the correct replacement.
Why do three cylinders share the same mounting distance but have different strokes?
Different tractor models — even within the same horsepower class — are designed with different lift linkage geometries. A machine that needs a wider implement position range needs a longer stroke cylinder. A machine with a more compact linkage needs a shorter stroke. The bracket spacing (mounting distance) may be standardized across a range of machines from the same manufacturer or family, while the stroke is tailored to the specific lift arm geometry of each model. That is why cylinders with the same 300 mm mounting distance exist in three stroke lengths — they fit the same bracket but serve machines with different travel requirements.
Does the 140 mm stroke provide more lifting force than shorter alternatives?
No. Force is a function of bore area and pressure, not stroke. All three cylinders in the 300 mm subgroup have the same 63 mm bore and will generate the same theoretical extension force at the same hydraulic pressure. Stroke only determines the distance over which that force is applied — the travel range. A 140 mm stroke cylinder does not push harder than a 100 mm stroke cylinder at the same bore and pressure; it pushes for 40 mm longer.
How do I measure stroke accurately on an installed cylinder?
With the machine safely supported and hydraulic pressure available, operate the lift control to fully retract the cylinder. Measure pin-center to pin-center — this is the mounting distance (should be 300 mm). Then extend the cylinder fully and measure pin-center to pin-center again. Subtract the retracted measurement from the extended measurement to get the stroke. For the QY350.59.003, extended length should be 440 mm: 440 − 300 = 140 mm stroke. Use a tape measure for pin-center distances; accuracy within 1–2 mm is sufficient to distinguish between the 100, 120, and 140 mm options in this subgroup.
My tractor implement slowly lowers on its own. Should I replace the cylinder?
Not before isolating where the leak is. Disconnect the hydraulic hoses from the cylinder and cap the cylinder’s ports using blanking plugs. Operate the lift to raise the implement, then release the control. If the implement holds position with ports capped, the cylinder is not the leak source — the problem is in the external circuit (control valve, check valve, or hose connections). If it still drifts with ports capped, the cylinder’s internal seals are a more likely candidate. This isolation test takes a few minutes and rules out an unnecessary cylinder replacement when the fault is actually in the valve circuit.
What information do I need before requesting a quote?
The most important detail for this subgroup is the confirmed stroke of 140 mm — without it, any of three cylinders could be correct. Also include: bore (63 mm), rod diameter (35 mm), mounting distance (300 mm), pin diameters at both ends, end connection type, port thread specification and number of ports, quantity, and machine model and year if known. Photos of the existing cylinder help confirm end connection geometry. If the cylinder is damaged and stroke cannot be directly measured, note that in the inquiry and include whatever partial measurements and documentation you have.
