Hydro Gear Lip Seal 51161 & 50735 – Fits MTD, Cub Cadet, Craftsman (Replaces 51161, 50735)
This replacement lip seal is designed for Hydro-Gear hydraulic pumps on various riding lawn tractors and outdoor power equipment. It is specifically compatible with Hydro-Gear BDA, BDP-10A, PE, PG, PJ, and PK Series pumps, which are commonly found in equipment from MTD, Cub Cadet, Craftsman, Troy Bilt, Bolens, and White Outdoors.
This component directly replaces Hydro Gear part numbers 51161 and 50735, and Husqvarna part number 583039301.
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Seal Dimensions: 17 x 40 x 7 mm (Inner Diameter x Outer Diameter x Width)
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Primary Application: Seals hydraulic pump shafts to prevent fluid leaks.
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Installation Method: Direct replacement for the original OEM seal.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
| Hydro Gear |
51161 |
| Hydro Gear |
50735 |
| Husqvarna |
583039301 |
Compatible Equipment Models
Confirm your engine model/year in the table below.
Hydro-Gear Pumps
| Brand |
Model |
Equipment Type |
OEM Part No. |
| Hydro-Gear |
BDA Series |
Hydraulic Pumps |
51161, 50735 |
| Hydro-Gear |
BDP-10A Series |
Hydraulic Pumps |
51161, 50735 |
| Hydro-Gear |
PE Series |
Hydraulic Pumps |
51161, 50735 |
| Hydro-Gear |
PG Series |
Hydraulic Pumps |
51161, 50735 |
| Hydro-Gear |
PJ Series |
Hydraulic Pumps |
51161, 50735 |
| Hydro-Gear |
PK Series |
Hydraulic Pumps |
51161, 50735 |
Compatible Equipment Brands
| Brand |
Equipment Type |
OEM Part No. |
Notes |
| Husqvarna |
Various Models |
583039301 |
Cross-referenced part number |
Technical Specifications
| Specification |
Value |
| Product Type |
Hydraulic Lip Seal |
| Installation |
Direct replacement |
| Dimensions |
17 x 40 x 7 mm (Inner Diameter x Outer Diameter x Width) |
| Housing Material |
Polyethylene (PE) |
| Housing Color |
Black |
| Weight |
0.025 kg (0.88 oz) |
| Other Technical Attributes |
For hydraulic pump shaft sealing applications |
Package Contents
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2 x Hydro Gear Lip Seal (Replaces 51161, 50735)
Installation Guide
- Ensure the equipment is safely powered off and secured on a level surface.
- Thoroughly clean the area around the hydraulic pump to prevent debris from entering the system.
- Carefully relieve any residual pressure from the hydraulic system according to the manufacturer's service manual.
- Remove any components obstructing access to the pump shaft seal.
- Using a seal puller or a flat-head screwdriver, carefully pry out the old lip seal, taking care not to scratch the shaft or housing.
- Inspect the pump shaft and the housing bore for any scoring, burrs, or damage. Clean the surfaces thoroughly.
- Lightly lubricate the inner lip of the new seal and the pump shaft with fresh hydraulic fluid.
- Position the new seal squarely over the housing bore. Gently and evenly press it into place using a seal driver or a socket with a matching outer diameter until it is fully seated.
- Reassemble all previously removed components.
- Refill the hydraulic system with the correct type of fluid and bleed any air from the system as per the equipment's service guide.
Troubleshooting & FAQ
Q: How do I know if this lip seal will fit my lawn tractor?
A: This seal is designed for Hydro-Gear BDA, BDP-10A, and PE, PG, PJ, and PK series pumps. It fits many riding mowers from MTD, Cub Cadet, Craftsman, and others using these pumps. Please verify your pump model and the part numbers 51161 or 50735. The seal dimensions are 17 x 40 x 7 mm.
Q: What are the signs that my hydro pump seal needs replacement?
A: Common signs include visible hydraulic fluid leaks around the pump shaft, a gradual loss of drive power, or a whining noise from the transmission, which can indicate fluid loss or air entering the system.
Q: Do I need any special tools for installation?
A: While standard mechanic's tools are often sufficient, a seal puller can make removing the old seal easier, and a seal driver (or a socket of the correct diameter) is recommended to install the new seal without damaging it.
Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.
Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.
Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.
Important Notes
- Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
- This product is an aftermarket replacement part and is not an OEM component.
- Professional installation is recommended to ensure safety and optimal performance.
Why Choose JLM MARINE?
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Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.