Why Does a Snow Plow Need a Double Acting Point-End Cylinder When Angling Under Load?

Moving a snow plow blade from side to side is relatively easy when the blade is unloaded. The real challenge begins after the blade has already entered wet snow, compacted snow, or a heavy roadside snowbank and still needs to change the discharge direction.

Under these conditions, one side of the blade may experience significantly more resistance than the other. Ice, road grit, and deicing salt may also accumulate around the blade pivot. The hydraulic cylinder must not only rotate the blade but also overcome offset loading, mechanical friction, and the effects of low-temperature hydraulic oil.

A Double Acting Point-End Cylinder uses hydraulic pressure to power both extension and retraction. This gives the snow plow controllable force in both directions. Its purpose is not simply to make the blade move, but to help the blade change direction, hold its position, and return to center while operating under changing loads.

Changing from Straight Pushing to Side Discharge

At the beginning of snow-clearing work, the blade may be positioned close to the center so that it pushes loose snow forward. As more snow collects in front of the blade, resistance increases. The operator then needs to angle the blade to the left or right so that the snow is discharged toward one side of the road.

During this movement, the cylinder extends to move the blade in one direction and actively retracts to move it in the opposite direction. The double acting structure allows the operator to control both movements directly instead of relying on snow pressure, gravity, or a return spring.

This two-way hydraulic control becomes especially important when:

• Wet, heavy snow is already pressing against the blade
• One side of the blade is close to a curb or snowbank
• Ice or debris has collected around the pivot
• The vehicle must change the discharge direction in a confined area
• The blade needs to return from its working angle to the transport position

If the retracting side cannot produce enough force, the blade may return smoothly when unloaded but move slowly or fail to return once snow resistance is applied.

A Moving Blade Does Not Always Mean the System Is Correctly Matched

A snow plow that can angle left and right has only demonstrated basic movement. It does not necessarily mean that the hydraulic system is properly matched to the real working conditions.

If the cylinder bore is too small, the system may appear normal during an unloaded test. Once the blade enters heavy snow, however, the cylinder may no longer provide sufficient force. Hydraulic pressure rises, but the blade moves slowly or stops before reaching the required angle.

Simply installing a larger cylinder is not always the correct answer. A larger piston area increases output force, but it also requires more hydraulic flow. If the existing pump and valve cannot supply enough flow, blade movement may become noticeably slower. Excessive cylinder force can also increase stress on the blade frame, pivot, and mounting brackets.

A snow plow cylinder must therefore balance several factors:

The objective is not to produce the maximum possible force at all times. The cylinder should move the blade smoothly under real snow resistance without placing unnecessary loads on the surrounding structure.

How Does the Point-End Connection Follow the Blade’s Movement?

When a snow plow changes angle, the blade rotates around its central pivot. The cylinder mounting points also move as the blade turns. As a result, the cylinder does not extend and retract along one perfectly fixed line. It must pivot slightly throughout the movement.

A point-end pin connection provides the freedom needed to accommodate this changing angle. As the cylinder moves, its end rotates around the mounting pin, allowing the cylinder body to follow the blade’s movement naturally.

This compact connection is suitable for snow plows with limited space behind the blade. However, the mounting brackets must provide enough movement. If the bracket spacing is too narrow, the pin is misaligned, or the cylinder body contacts the frame at a certain angle, the piston rod may be forced to operate under continuous side loading.

Side loading may not stop the cylinder immediately, but it can gradually cause:

• Uneven wear between the piston rod and guide
• One-sided compression of the seals
• Scratches on the rod surface
• Increasing clearance around the pin holes
• Jerky movement during extension or retraction
• Premature leakage around the sealing area

After installation, the cylinder should not be checked only with the blade in the center position. The blade should also be moved fully left and fully right to confirm that adequate clearance remains around the cylinder, the hoses do not become tight, and the rod remains properly aligned.

The Blade Must Remain Stable After Reaching Its Working Angle

Once the snow plow has turned to one side, the hydraulic operation is not finished. During snow clearing, the blade surface continues to experience uneven pressure from the accumulated snow.

This pressure may try to push the blade back toward the center or force it farther toward one side. The hydraulic cylinder and control valve must work together to hold the selected blade position.

If the valve has internal leakage or the piston seals allow oil to pass internally, the blade may gradually change angle during operation. At first, only a slight change in the snow discharge direction may be noticed. Over time, the operator may need to readjust the blade frequently.

Possible signs of internal leakage include:

• The blade moves after the angle has been set
• Holding performance differs between the left and right positions
• The angle changes even though no external oil leak is visible
• The hydraulic system repeatedly rebuilds pressure
• Movement in one direction is noticeably weaker than in the other

Blade drift is not always caused by the cylinder. The control valve, hydraulic connections, and system pressure should also be inspected.

The End of the Cylinder Stroke Should Not Replace a Mechanical Blade Stop

Snow plows normally have a maximum left and right working angle. If the piston is forced against the cylinder’s internal stroke limit every time the blade reaches either side, repeated hydraulic shocks will be transferred to the piston, cylinder head, mounting pins, and blade frame.

A more suitable design uses external mechanical stops on the blade structure to define the final working angle. The cylinder should approach the end of its stroke as the stop is reached, rather than absorbing the full stopping force internally during every cycle.

Stroke selection should include:

• Maximum left blade angle
• Maximum right blade angle
• Fully retracted cylinder length
• Fully extended cylinder length
• Change in distance between the mounting points
• Position where the external stops make contact

Matching only the stroke length of the original cylinder is not enough. If the new cylinder has a different body length, end structure, or retracted dimension, it may not fit correctly even when the stroke is identical.

The Piston Rod Surface Is Often the Most Overlooked Part in Winter

Snow plow cylinders are normally installed close to the ground. During operation, the exposed piston rod comes into contact with water, grit, deicing salt, and small ice particles.

When the rod retracts, these contaminants move toward the wiper. If the rod surface has already developed corrosion or scratches, the wiper may not remove the contamination completely. Fine particles can then reach the sealing area.

The condition of the piston rod directly affects the cylinder’s ability to remain sealed over time. Important inspection points include:

• Rust spots on the chrome-plated surface
• Impact marks or dents on the piston rod
• Salt and grit collected around the wiper
• Increasing oil film around the cylinder opening
• Long periods of storage with the rod fully exposed

Cleaning salt and dirt after operation and reducing the exposed rod length during storage can lower the risk of corrosion and seal wear.

How Can the WEITAI WDP Series Match Different Snow Plow Designs?

The WEITAI WDP Series is a range of Double Acting Point-End Cylinders with bore sizes from 40 mm to 80 mm. Depending on the cylinder bore, piston rod diameters range from 20 mm to 40 mm, while available stroke lengths generally extend from approximately 100 mm to 600 mm.

These configurations can be matched to compact snow plows, agricultural blades, wheel loader attachments, and other mobile equipment requiring powered push-and-pull movement.

WEITAI hydraulic cylinders undergo inspections covering raw materials, dimensions, welding, chrome-plated surfaces, and assembly quality. Completed cylinders are also pressure- and leakage-tested to confirm their performance during repeated outdoor operation.

Conclusion

The main challenge in a snow plow hydraulic system is not making the unloaded blade move from side to side. It is ensuring that the blade can still change direction accurately and hold the selected angle when snow resistance, low temperature, offset loads, and contamination occur at the same time.

A Double Acting Point-End Cylinder uses hydraulic pressure in both directions, allowing the blade to turn left, turn right, and return to center without depending on an external return force.

The point-end pin connection follows the curved movement of the blade, while the correct bore, stroke, piston rod, and mounting geometry determine whether the system can operate reliably over time.

The WEITAI WDP Series offers multiple bore, stroke, and port combinations for matching different snow plows and mobile machines. The final cylinder configuration should still be selected according to the blade geometry, operating pressure, available installation space, and actual winter working conditions.

Frequently Asked Questions

Why can a snow plow blade turn when unloaded but not when pushing snow?

Common causes include insufficient cylinder force, low system pressure, excessive pivot resistance, ice blocking the mechanism, or poor linkage geometry that produces an inadequate effective lever arm.

Why do point-end cylinder seals wear prematurely after installation?

If the mounting pins are not aligned, the brackets do not provide enough pivoting movement, or the cylinder contacts the frame, the piston rod may operate under side loading and cause uneven wear on the guide and seals.

Is a longer cylinder stroke always better for a snow plow?

No. Stroke must match the required blade angle and mounting-point movement. Excessive stroke can create conflicts with the mechanical stops and increase pressure shocks near the end of travel.

Which parameters are needed to select a WDP Series cylinder?

The main parameters include bore size, piston rod diameter, stroke, retracted length, mounting-pin dimensions, port standard, system pressure, blade angle, and available installation space.