Tractor Power Steering Cylinder | 63mm Bore 40mm Rod 285mm Stroke

Tractor Power Steering Cylinder — 63 mm Bore × 285 mm Stroke Heavy-Rod Long-Travel Hydraulic Steering Ram

Bore Diameter	63 mm
Rod Diameter	40 mm
Stroke	285 mm
Mounting Distance (C-C)	730 mm
Cylinder Type	Double-Acting, Single Body
応用	Large Agricultural Tractor Front Axle
Seal Material	PU Primary + NBR Backup

Request Pricing — Large-Platform Steering Cylinder

63 mm bore · 40 mm rod · 285 mm stroke · 730 mm C-C · FOB Ningbo

Engineering Overview: 63 mm Bore 40 mm Rod 285 mm Stroke — The Longest-Travel Heavy-Rod Tractor Power Steering Cylinder in This Range

This Tractor Power Steering Cylinder carries the most demanding dimensional specification in the entire twelve-product series: the longest stroke (285 mm), the longest C-C mounting distance (730 mm), and the thickest rod (40 mm) among all single-body cylinders reviewed here. It shares its 63 mm bore with the QJ904.31.019 (Product 10) but diverges significantly in every other parameter. The 40 mm rod in a 63 mm bore produces a bore-to-rod area ratio of 2.49:1—close to the ratio seen in mid-range cylinders—but the structural intention is different: rather than optimising retract force balance, the 40 mm rod is specified primarily to achieve a high buckling safety factor at the extreme 285 mm stroke length.

Under fixed-pinned end conditions, the 40 mm rod at 285 mm effective stroke has an Euler buckling load of approximately 210 kN—a 5.6× safety factor over the 37.4 kN rated extension force at 12 MPa. This is the highest buckling safety margin in the series, reflecting a conservative engineering approach for a cylinder that will be fitted to large tractors operating in applications with high lateral shock loads: deep subsoiling, heavy disc harrowing on stony ground, and primary cultivation in heavy clay soils where front axle impact loads are unpredictable and potentially severe. The 730 mm C-C is the longest bracket span in the series and is consistent with the wide front axle beam sections used on large-platform tractors where the front beam must span the full tyre width with structural clearance on both sides.

Unlike Products 8–11, this cylinder carries no OEM-specific model prefix in its product title, indicating it is supplied as a universal-fit replacement part serving several large-tractor chassis that share the 63 mm bore / 40 mm rod / 285 mm stroke / 730 mm C-C specification across different OEM part numbering systems. This makes the dimensional verification process even more critical: without a single authoritative OEM part number to cross-reference, procurement decisions must be based entirely on confirmed dimensional data rather than part number lookup.

Hydraulic Specifications: Force Output, Maximum Stroke Volume, Pump Demand, and Seal Kit for the 63 mm × 285 mm Heavy-Rod Tractor Steering Cylinder

Bore area is 3,117 mm²; rod area is 1,257 mm² (40 mm rod). At 12 MPa, extension force is 37.4 kN and retract force is 22.3 kN—a retract-to-extend ratio of 60%. Full extension displaces 888 cm³, the highest single-body stroke volume in this series. For a 2.0-second lock time, the minimum required pump flow is 26.7 L/min. This demand level confirms that this cylinder is intended for large-platform tractors with high-capacity hydraulic systems; fitting it to a machine with a pump output below 22 L/min will produce noticeably slow lock times that compromise operational efficiency during headland turns. The 40 mm rod reduces the retract side annular area to 1,860 mm² (bore area minus rod area), producing a retract force of 22.3 kN—lower than the QJ1254’s 27.6 kN retract force despite sharing the same 63 mm bore, because the thicker 40 mm rod displaces more of the rod-side hydraulic area. Operators should confirm that the tractor’s steering circuit includes an adequately sized return-side accumulator or flow control to manage the asymmetric extend/retract flow rates without inducing circuit pressure spikes.

Barrel tube is 20# seamless precision steel, bore honed to Ra ≤ 0.4 µm. The 285 mm stroke is the longest honing run in this series, and bore taper control requires careful monitoring across the full length. Rod is 40Cr alloy steel (AISI 5140), heat-treated to 28–32 HRC, hard chrome plated to 30–35 µm—a step up from the 25–30 µm standard used on shorter-stroke cylinders, specified here because the 285 mm exposed rod length at full extension represents the largest corrosion-risk surface in the series and the additional plating thickness extends the chrome service life proportionally. Post-plating, the rod is precision-ground to h6 tolerance on the 40 mm diameter (±11 µm). Seal kit: PU piston U-ring rated to 20 MPa dynamic, NBR O-ring secondary, PU rod U-seal, and reinforced-fabric PU wiper seal sized for the 40 mm rod OD. The 40 mm wiper seal is a distinct size from the 35 mm and 36 mm wipers used on Products 10 and 11; ensure the correct wiper size is specified when ordering replacement seal kits.

Fitment Verification: Universal-Fit 730 mm C-C Identification, 40 mm Rod Clevis Pin Specification, and Cross-Platform Dimensional Matching for This Heavy-Rod Steering Cylinder

Without a single-brand OEM part number, the verification process for this cylinder relies entirely on dimensional confirmation. Measure the existing cylinder’s retracted C-C distance, bore diameter (from the port bore if the barrel is accessible), rod diameter with a micrometer, and clevis pin bore diameter. Clevis pin bores on this cylinder are 35 mm H7 at both ends—the largest clevis pin specification in this series—matching the 35f7 pin standard on the widest-platform front axle beam brackets. The five-parameter signature: 63 mm bore, 40 mm rod, 285 mm stroke, 730 mm C-C, 35 mm clevis pin. This combination is sufficiently distinctive that a correct five-parameter match has a very low probability of producing a false positive from an incompatible cylinder. For distributors maintaining an inventory of large-bore steering cylinders, the 35 mm clevis pin is the fastest single-point differentiator from adjacent products—the QJ1254 uses 34 mm, the QJ904 uses 32 mm, making the 35 mm pin a unique identifier for this model within the large-bore segment.

Installation, Flow Asymmetry Management, and Long-Stroke Maintenance Procedures for the 63 mm × 285 mm Heavy-Rod Tractor Power Steering Cylinder

Torque 35 mm clevis pin retention fasteners to 90–100 N·m. Port connections are M22×1.5; torque to 90–105 N·m with new bonded seals. Fill the hydraulic reservoir to maximum; expect a 2.0–2.5 litre absorption during initial cylinder fill and reservoir top-up after bleed. Bleed with ten full lock-to-lock cycles at low idle, followed by two cycles at normal operating RPM. After bleeding, check for consistent steering feel in both directions—the 37.4 kN vs. 22.3 kN extend/retract force asymmetry is more pronounced than in most other cylinders in this series; if the operator notices a notably heavier feel when steering in the retract direction under load, this is within the normal force differential for this rod-to-bore ratio and is not a cylinder fault. Confirm the existing steering circuit includes a flow control or counterbalance valve on the rod-side port if the original equipment did; removing or bypassing this valve during installation will expose the rod-side port to uncontrolled back-pressure that can damage the rod seal. Wiper seal inspection at 500-hour intervals; full seal kit replacement at 2,000 hours standard or 1,500 hours in stony-ground subsoiling applications.

Quality Assurance, 285 mm Stroke Bore Taper Protocol, and B2B Procurement for the 63 mm Heavy-Rod Long-Travel Tractor Steering Cylinder

Proof test at 21 MPa static produces approximately 65.5 kN on the test rig fixture. Test protocol: 5 minutes per stroke direction static; 20 dynamic cycles at rated pressure. Bore taper measurement at five axial positions (additional measurement points vs. standard three-point protocol, to account for the longer 285 mm bore length): 10 mm from each end, at one-quarter stroke, at mid-stroke, and at three-quarter stroke. Acceptance criterion: ≤0.015 mm diameter variation across all five positions. Internal leakage: ≤4 mL/min at the piston seal. Chrome rod sample testing: 240-hour ASTM B117 per batch at the 30–35 µm plating specification. Barrel exterior: two-component epoxy primer as standard; electroless nickel plating upgrade available for marine-adjacent or high-humidity storage environments. MOQ: 10 units; standard pallet: 20 units. Lead time: 12–18 working days FOB Ningbo (longer scheduling due to 285 mm long-stroke bore honing and 40 mm rod chrome plating lead time). Custom options: alternative port thread standards, FKM seals, heavy-chrome rod plating upgrade, modified C-C for non-standard axle variants. OEM white-label documentation available in English, Spanish, Portuguese, Korean, and Dutch.