{"id":1475,"date":"2026-08-26T05:21:55","date_gmt":"2026-08-26T05:21:55","guid":{"rendered":"https:\/\/ever-powers.com\/?post_type=product&p=1475"},"modified":"2026-08-26T05:23:43","modified_gmt":"2026-08-26T05:23:43","slug":"ym4p-83k-05-corn-harvester-steering-cylinder","status":"publish","type":"product","link":"https:\/\/ever-powers.com\/fr\/product\/ym4p-83k-05-corn-harvester-steering-cylinder\/","title":{"rendered":"Corn Harvester Steering Cylinder YM4P.83K.05 \u2013 40mm Bore, 190mm Stroke"},"content":{"rendered":"
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YM4P.83K.05 \u00b7 Corn Harvester Series<\/p>\n

Corn Harvester Steering Cylinder<\/h2>\n

Double-acting, high-cycle steering actuator for the rear-axle power steering system of 4-row self-propelled corn harvesters \u2014 engineered for symmetrical response, zero drift, and 10,000+ cycle seasonal durability.<\/p>\n

Bore 40 mm<\/span>
\nRod 25 mm<\/span>
\nStroke 190 mm<\/span>
\nC\/C 387 mm<\/span>
\nPart No. YM4P.83K.05<\/span><\/div>\n<\/div>\n
\"YM4P.83K.05<\/div>\n<\/div>\n

<\/p>\n

Full Specification at a Glance<\/p>\n

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Bore Diameter<\/p>\n

40 mm<\/span><\/p>\n

Push force \u2248 20.1 kN @ 160 bar \u2014 sufficient for full rear-axle steering load<\/p>\n<\/div>\n

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Rod Diameter<\/p>\n

25 mm<\/span><\/p>\n

Rod\/bore ratio 0.625 \u2014 near-symmetric push\/pull for equal left\/right steering response<\/p>\n<\/div>\n

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Stroke<\/p>\n

190 mm<\/span><\/p>\n

Full lock-to-lock rear axle travel on 4-row platform geometry<\/p>\n<\/div>\n

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Mounting Distance<\/p>\n

387 mm<\/span><\/p>\n

C\/C retracted. Extended: 577 mm. Governs rear axle bracket geometry.<\/p>\n<\/div>\n

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Rated Pressure<\/p>\n

160 bar<\/span><\/p>\n

Continuous working pressure \u2014 shared steering\/hydraulic circuit<\/p>\n<\/div>\n

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Surge Pressure<\/p>\n

220 bar<\/span><\/p>\n

Kerb-strike and hard-lock shock rated \u2014 proof tested per unit<\/p>\n<\/div>\n

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Cycle Rating<\/p>\n

10,000+<\/p>\n

Full lock-to-lock cycles before seal service \u2014 lab endurance verified<\/p>\n<\/div>\n

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Internal Leakage<\/p>\n

\u2264 2 cc\/min<\/span><\/p>\n

Tightest spec in this cylinder family \u2014 steering drift is a safety issue<\/p>\n<\/div>\n

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Rod Chrome<\/p>\n

25\u201330 \u00b5m<\/span><\/p>\n

Hard chrome HV 800+. Rear axle position \u2014 mudpack and stone chip exposure<\/p>\n<\/div>\n

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Mounting Style<\/p>\n

Clevis \u00d7 2<\/p>\n

\u00d818 mm pin bore both ends \u2014 smaller pin reflects lower bending moment on short-stroke steering linkage<\/p>\n<\/div>\n<\/div>\n

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Push Force (Left Lock)<\/p>\n

20.1 kN<\/p>\n

F = 160 bar \u00d7 \u03c0\/4 \u00d7 40\u00b2<\/p>\n<\/div>\n

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Pull Force (Right Lock)<\/p>\n

15.2 kN<\/p>\n

F = 160 bar \u00d7 \u03c0\/4 \u00d7 (40\u00b2\u221225\u00b2)<\/p>\n<\/div>\n

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Force Asymmetry<\/p>\n

1.32 : 1<\/p>\n

The tightest push\/pull ratio in this cylinder family \u2014 essential for equal left and right steering feel<\/p>\n<\/div>\n

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Lock-to-Lock Time<\/p>\n

\u2248 1.4 s<\/p>\n

At 8 L\/min dedicated steering circuit flow \u2014 responsive without being twitchy at field speeds<\/p>\n<\/div>\n<\/div>\n

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The YM4P.83K.05 corn harvester steering cylinder<\/strong> is the only cylinder in this six-unit set that is directly coupled to operator safety. Every other cylinder on this machine controls an agricultural function \u2014 header height, grain discharge, chopper gap. This one controls where the machine goes. A sticking engagement cylinder costs time; a compromised steering cylinder on a 10-tonne self-propelled harvester travelling a headland at 8 km\/h costs significantly more.<\/p>\n

That framing is not alarmist \u2014 it is the engineering justification for why the steering cylinder carries the tightest internal leakage specification (\u2264 2 cc\/min), the highest cycle-endurance rating (10,000+ full lock-to-lock), and the most conservative surge pressure rating (220 bar) of any cylinder on this harvester. It is also why the rod diameter of 25 mm \u2014 giving a push\/pull force ratio of just 1.32:1 \u2014 is selected specifically to minimise left-right steering force asymmetry rather than to maximise push force, as would be the design priority on a lift or dump cylinder.<\/p>\n

For OEM engineers and parts procurement managers: this cylinder is not interchangeable with a generic 40\/25 agricultural cylinder. The sealing system, cycle rating, and leakage specification are steering-duty specific. Understanding why each parameter is set as it is \u2014 and what degrades when it is not met \u2014 is the basis for making the correct sourcing decision.<\/p>\n

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\"Self-propelled<\/p>\n

Every headland turn and field-pass correction runs through the steering cylinder \u2014 cycle count accumulates faster than any other actuator on the machine<\/p>\n<\/div>\n

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Hydraulic Steering Cylinder for Self-Propelled Corn Harvester \u2014 Engineering Rationale Behind Each Specification<\/h2>\n

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Q<\/div>\n
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Why is the push\/pull ratio only 1.32:1 \u2014 far lower than the chopper cylinder’s 4.53:1 or the header lift’s 4.54:1?<\/p>\n

Steering cylinders are the one application in agricultural hydraulics where push\/pull force asymmetry translates directly into a driver experience problem. If the cylinder generates 20.1 kN turning left but only 8.7 kN turning right, the operator must apply noticeably different input force on the steering valve to achieve the same lock speed in each direction. On a joystick-steered or manually piloted harvester, this asymmetry is immediately felt and creates operator fatigue, imprecise headland alignment, and \u2014 on slopes \u2014 a tendency to drift toward the high-force direction when the operator relaxes input.<\/p>\n

The 25 mm rod on a 40 mm bore gives an annular area of 755 mm\u00b2 versus a full bore area of 1,257 mm\u00b2 \u2014 a ratio of 0.60. This produces 15.2 kN retract against 20.1 kN extend: a 1.32:1 ratio that is close enough to symmetric for the driver to feel no meaningful difference between left and right lock. Every millimetre added to the rod diameter beyond 25 mm would worsen this balance. The specification is a deliberate steering-feel decision, not a default.<\/p>\n<\/div>\n<\/div>\n

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Q<\/div>\n
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Why does the steering cylinder accumulate more cycles per season than any other actuator on the machine?<\/p>\n

Consider the operating pattern. A dump cylinder cycles once every 15\u201325 minutes of harvesting \u2014 perhaps 30\u201340 times per day. The header lift cylinder moves 10\u201320 times per hour as the operator raises and lowers for headland turns. The steering cylinder, by contrast, moves continuously: every row correction, every headland pivot, every obstacle avoidance input, every adjustment to cross-slope drift. On a 10-hour harvest day with 200 m rows and 90\u00b0 headland turns, a conservative estimate yields 400\u2013600 partial stroke steering inputs and 80\u2013120 full or near-full lock manoeuvres.<\/p>\n

Over a 30-day season, this accumulates to 12,000\u201318,000 steering events \u2014 ranging from minor directional corrections (5\u201320% stroke) to full lock-to-lock turns. The 10,000+ full-cycle laboratory endurance rating corresponds to this real-world seasonal load. A cylinder with a lower cycle rating \u2014 or, more commonly, one that meets cycle count targets only in a clean laboratory environment without the road grit, mud, and chaff contamination of rear-axle duty \u2014 will begin showing rod seal weep within 1\u20132 seasons.<\/p>\n<\/div>\n<\/div>\n

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Q<\/div>\n
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Internal leakage is specified at \u2264 2 cc\/min \u2014 tighter than any other cylinder in this set. What goes wrong at higher leakage rates?<\/p>\n

On a lift or dump cylinder, internal piston seal leakage manifests as slow position drift \u2014 annoying, but correctable by the operator. On a steering cylinder, internal bypass has a qualitatively different consequence: under sustained side loading \u2014 crosswind, side slope, or road camber \u2014 the cylinder will slowly drift toward the low-pressure side as oil bypasses the piston seal from the high-pressure port to the low-pressure port. The machine steers itself toward the ditch.<\/p>\n

Quantifying the threshold: at 5 cc\/min internal leakage (the spec limit for the grain tank lift cylinder), a steering cylinder under 80 bar sustained side load drifts approximately 2.5 mm\/min. Over 4 minutes of straight-ahead harvesting without active operator correction, that is 10 mm of cylinder travel \u2014 roughly 3\u20134\u00b0 of rear axle angular error, enough to walk the machine off-row by 0.3\u20130.5 m per field length. At \u2264 2 cc\/min, that error drops to under 1.5\u00b0 over the same period \u2014 within normal operator correction frequency. The \u2264 2 cc\/min limit is the engineering threshold below which passive drift is invisible to an attentive operator.<\/p>\n<\/div>\n<\/div>\n

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Q<\/div>\n
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What makes rear-axle steering the most hostile contamination environment for a cylinder on this machine?<\/p>\n

The steering cylinder lives in the most contaminated position on the harvester. Unlike the header, grain tank, or chopper cylinders \u2014 which are in the machine’s upper or mid structure \u2014 the rear-axle steering cylinder is at ground level, directly exposed to mud spray from the rear tyres, stone chip from turns on headland tracks, water from stream crossings, and the compacted soil paste that accumulates on rear axle components after a rain delay.<\/p>\n

This exposure pattern drives three specification decisions: (1) the double-lip wiper with a reinforced steel exclusion lip rather than a standard single-lip \u2014 the outer lip physically shears mud plugs from the rod on every retract stroke; (2) chrome depth of 25\u201330 \u00b5m rather than 18\u201320 \u00b5m typical of sheltered-position cylinders \u2014 thicker chrome survives stone chip impacts without exposing the steel substrate; (3) full external paint system with 80 \u00b5m minimum DFT and zinc phosphate conversion coating rather than bare phosphate \u2014 the rear axle environment routinely fails 240-hour salt spray test specimens that would pass comfortably in a mid-machine position.<\/p>\n<\/div>\n<\/div>\n

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Q<\/div>\n
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The surge pressure is 220 bar \u2014 what events generate surges in a steering cylinder that would not occur in a lift or dump cylinder?<\/p>\n

Two events are specific to steering duty. First: hard-lock impact. When the rear axle reaches full steering lock against the mechanical stop and the operator continues to hold steering input \u2014 a routine occurrence, particularly during tight headland turns \u2014 the full circuit pressure is applied to a stationary cylinder against a rigid stop. On a machine with a pressure-compensated steering circuit, this saturates at relief valve setting; on a fixed-displacement circuit, the pressure spike can briefly exceed 200 bar before the relief opens. The 220 bar surge rating ensures the cylinder tube and end-cap welds are not the weakest element in this event. Second: obstacle impact on the rear axle. Driving over a large stone or buried root at field speed transmits an impulsive lateral force through the rear steering linkage into the cylinder in the retract direction. This generates a rod-side pressure spike that bypasses the circuit relief valve on the timescale of the impact. The 220 bar rating covers the estimated peak of this event for the platform weight class this machine falls into.<\/p>\n<\/div>\n<\/div>\n

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Agricultural Power Steering Cylinder \u2014 Construction and Material Standards for Rear-Axle Duty<\/h2>\n
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Cylinder Tube<\/p>\n

E355 cold-drawn seamless, 40 mm bore \u00d7 7 mm wall. Honed Ra \u2264 0.4 \u00b5m. External: zinc phosphate conversion coat + two-coat PU topcoat, 80 \u00b5m minimum DFT. Salt-spray tested 500+ hours. All external machined faces passivated before painting.<\/p>\n<\/div>\n

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Chrome Rod<\/p>\n

Ck45 steel, ground Ra \u2264 0.2 \u00b5m. Hard chrome 25\u201330 \u00b5m, HV 800+. Post-chrome ground to h6. Stone-chip resistance is a primary selection criterion at 25 mm diameter \u2014 chrome adhesion spec requires \u2265 35 N\/mm\u00b2 bond strength, verified by scratch test on production batches.<\/p>\n<\/div>\n

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Wiper \/ Seal Pack<\/p>\n

Double-lip wiper: reinforced steel exclusion outer lip + PU inner lip. Inner rod seal: dual-lip PU rated to 10,000 full-stroke cycles. Piston: quad-ring PU + PTFE backup. Bronze guide ring with widened contact face for lateral load management in side-loaded steering duty.<\/p>\n<\/div>\n

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End Fixings<\/p>\n

Clevis both ends, \u00d818 mm pin bore. Sintered bronze self-lubricating bush \u2014 no grease nipple required on standard spec (grease-nipple option available). Clevis eyes machined to H7 for pin fit. Locking: castellated gland nut with tab washer.<\/p>\n<\/div>\n

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QC Protocol<\/p>\n

Hydrostatic proof 220 bar \u00d7 60 s per unit. Full-stroke \u00d7 10 cycles (double the standard protocol \u2014 steering duty). Leakage both ports: \u2264 2 cc\/min verified at rated pressure. Dimensional audit: C\/C, stroke, pin bore. Records retained per batch.<\/p>\n<\/div>\n<\/div>\n

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\"Corn<\/p>\n

Straight-row tracking and precise headland turning both depend on the steering cylinder maintaining zero-drift position hold between active steering inputs<\/p>\n<\/div>\n

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Fitment Verification \u2014 Critical Dimensions for Replacement and Cross-Reference<\/h2>\n

Steering cylinder replacement is higher stakes than other cylinders on this machine: an incorrect C\/C or stroke dimension changes the maximum steering angle, which directly affects minimum turning radius and headland manoeuvrability. Verify all four dimensions before ordering.<\/p>\n

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C\/C Retracted<\/p>\n

387 mm<\/p>\n

Primary bracket dimension. A 10 mm error here changes the straight-ahead axle geometry.<\/p>\n<\/div>\n

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Stroke<\/p>\n

190 mm<\/p>\n

Determines full steering lock angle. Short-stroke substitute reduces turning circle.<\/p>\n<\/div>\n

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Pin Bore<\/p>\n

\u00d818 mm<\/p>\n

Both ends. Smaller than other cylinders in this set \u2014 confirm pin diameter on machine.<\/p>\n<\/div>\n

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Rod Diameter<\/p>\n

25 mm<\/p>\n

Do not substitute larger rod \u2014 changes force asymmetry and steering feel. See above.<\/p>\n<\/div>\n

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Port Thread<\/p>\n

BSP G3\/8″<\/p>\n

Steering circuit typically uses smaller port sizes than lift circuits. Confirm hose fittings before ordering.<\/p>\n<\/div>\n<\/div>\n

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OEM Corn Harvester Hydraulic Steering Actuator \u2014 Custom Specifications for Platform Integrators<\/h2>\n

Steering geometry varies more between machine platforms than any other hydraulic function \u2014 axle pivot positions, tie-rod lengths, and kingpin offsets all interact with cylinder stroke and C\/C to produce the target steering angle. Custom configurations are supported across the following parameters:<\/p>\n