Product Overview
The WIX 51551 Heavy Duty Spin-On Hydraulic Filter is designed to effectively remove particle contaminants from hydraulic fluid systems. This ensures the longevity and optimal performance of hydraulic components by providing a clean fluid path, reducing wear, corrosion, and abrasion.

Image: The WIX 51551 Heavy Duty Spin-On Hydraulic Filter, showing its light blue casing with the WIX logo, "FILTERS", "51551", and "FLUID POWER FILTER" printed on it. The top of the filter, where it spins on, is visible.
Setup and Installation
Proper installation is crucial for the filter's performance and system integrity. Always refer to your equipment's service manual for specific instructions and safety precautions before beginning installation.
- Preparation: Ensure the hydraulic system is depressurized and cooled. Place a drain pan beneath the filter to catch any fluid spills.
- Removal of Old Filter: Carefully unscrew the old hydraulic filter. Dispose of the old filter and any collected fluid according to local environmental regulations.
- Gasket Lubrication: Apply a thin film of clean hydraulic fluid to the new filter's gasket. This helps ensure a proper seal and prevents the gasket from tearing during installation.
- Installation of New Filter: Thread the new WIX 51551 filter onto the filter head. Hand-tighten until the gasket makes contact with the sealing surface. Then, tighten an additional 1/2 to 3/4 turn, or as specified by your equipment manufacturer. Do not overtighten.
- System Priming and Check: Refill the hydraulic reservoir to the appropriate level with the recommended hydraulic fluid. Start the equipment and check for any leaks around the new filter. Operate the system briefly to circulate fluid, then recheck the fluid level and top off if necessary.
Operating Principles
The WIX 51551 hydraulic filter operates by filtering contaminants from the hydraulic fluid as it passes through the filter media. Its design provides a linear path for low flow restriction, ensuring efficient fluid circulation while effectively trapping harmful particles. This continuous filtration process is vital for maintaining the cleanliness of the hydraulic system, which in turn protects pumps, valves, and cylinders from premature wear and failure.
Maintenance
Regular maintenance, primarily filter replacement, is essential for the longevity and efficiency of your hydraulic system. The frequency of replacement depends on the operating conditions, fluid contamination levels, and the equipment manufacturer's recommendations.
- Replacement Schedule: Consult your equipment's service manual for the recommended hydraulic filter change interval. In demanding applications or dusty environments, more frequent changes may be necessary.
- Visual Inspection: Periodically inspect the filter and surrounding area for signs of leaks or damage.
- Fluid Analysis: For critical systems, fluid analysis can help determine the optimal filter change interval by monitoring fluid cleanliness and degradation.
Troubleshooting
If you experience issues with your hydraulic system, consider the filter as a potential factor. Always consult a qualified technician for complex issues.
- Reduced Hydraulic Flow/Pressure: A clogged or restricted hydraulic filter can lead to reduced flow or pressure in the system. This indicates the filter needs immediate replacement.
- Unusual Noises: A severely restricted filter can cause the hydraulic pump to cavitate, leading to unusual noises.
- Fluid Contamination: If the hydraulic fluid appears cloudy, discolored, or contains visible particles shortly after a filter change, it may indicate an issue with the filter's sealing, an incorrect filter, or severe system contamination.
- Leaks Around Filter: Check that the filter is properly tightened and the gasket is not damaged. Ensure the sealing surface on the filter head is clean and free of debris.
Specifications
| Brand | Wix |
| Model Number | 51551 |
| Material | Paper |
| Product Grade | Performance Part |
| Item Dimensions (L x W x H) | 3.9 x 3.9 x 5.3 inches |
| Thread Size | 3/4-16 |
| Item Weight | 8 ounces |
| UPC | 765809515512 |
Warranty and Support
For specific warranty information regarding the WIX 51551 Hydraulic Filter, please refer to the official WIX Filters website or contact their customer support directly. Warranty terms and conditions may vary based on region and purchase location.
For technical support or further assistance, it is recommended to contact WIX Filters customer service or consult with a certified automotive or hydraulic system technician.

