UL125-0.375-250B is a loaded polyurethane U-Cup seal designed to help stop hydraulic leaks, restore cylinder performance, and reduce equipment downtime. The loaded design uses a polyurethane sealing body with a Buna-N O-Ring energizer to improve sealing force, especially where consistent lip loading matters.
UL125-0.375-250B is a 3/8" ID X 5/8" OD X 1/4" HT loaded polyurethane U-Cup seal for hydraulic rod or piston sealing applications.
This seal is a good choice for hydraulic repair shops, maintenance teams, and equipment owners who need a dependable replacement seal by size. Based on the UL Series naming shown in the uploaded reference, UL Series parts are loaded U-Cups with a polyurethane body and Buna-N O-Ring energizer.
Operating Temperature
Operating temperature: -40° to +230°F (-40° to +110°C)
Material & Performance Details
This loaded U-Cup seal uses a polyurethane body for wear resistance, abrasion resistance, and extrusion resistance in hydraulic cylinder service. The Buna-N O-Ring energizer helps maintain lip contact and sealing force, which can improve performance in worn or lower-pressure conditions.
The U-Cup profile is commonly used where hydraulic fluid pressure energizes the sealing lips against the rod or bore surface. The loaded design adds extra sealing support compared to an unloaded U-Cup.
- Excellent resistance to:
- Petroleum-based hydraulic oils
- Abrasion and wear
- Extrusion under pressure
- Repeated cylinder movement
- General hydraulic service conditions
- Limited capability with:
- Some synthetic fluids
- High-temperature fluids beyond the material rating
- Applications with aggressive chemicals
- Not compatible with:
- Fluids that are not suitable for polyurethane or Buna-N
- Unknown chemical service without review
Final compatibility should be verified against the hydraulic fluid, pressure, temperature, and equipment conditions.
Sizes & Measurements
- Dimensions: 3/8"ID X 5/8"OD X 1/4"HT
- Actual: 0.375"ID X 0.625"OD X 0.250"HT
- Metric: 9.53mm ID X 15.88mm OD X 6.35mm HT
- Part Number: UL125-0.375-250B
- Profile: Loaded U-Cup
- Seal Type: Hydraulic loaded U-Cup seal
- Rod Size: 3/8"
- Bore Size: 5/8"
- Cross Section: 1/8"
- Height: 1/4"
- Cross References: Not specified
Applications & Use Cases
UL125-0.375-250B is used in hydraulic cylinders where a compact loaded U-Cup seal is needed to control fluid leakage and keep equipment working. It may be used in rod sealing or piston sealing applications when the gland design matches the seal profile and dimensions.
Typical uses include hydraulic cylinders, mobile hydraulics, agricultural equipment, construction equipment, dump trailers, forklifts, log splitters, presses, pumps, valves, MRO work, and hydraulic repair shops.
The customer benefit is simple: better fit identification, fewer wrong-part orders, faster repairs, and less downtime when a cylinder needs to be resealed.
Key Specifications
- Material: Polyurethane body with Buna-N O-Ring energizer
- Durometer: Not specified
- Color: Not specified
- Seal Type: Loaded U-Cup seal
- Profile: UL Series loaded U-Cup
- Application: Hydraulic cylinder sealing
- Rod or Bore Use: Rod or piston use depending on gland design
- Temperature Range: -40° to +230°F (-40° to +110°C)
- Pressure Rating: Not specified
- Surface Speed: Not specified
- Fluid Compatibility: Petroleum-based hydraulic fluids, final compatibility must be verified
- Certifications: Not specified
- Country of Origin: Not specified
- Brand or Manufacturer: Not specified
Why Buy from The O-Ring Store LLC
Buying UL125-0.375-250B from The O-Ring Store LLC helps you get the right hydraulic seal faster and with less guesswork. We are ISO9001:2015 certified, stock hydraulic seals in the USA for fast delivery, and offer same-day shipping on in-stock items when order requirements are met. Our team helps identify seals by size, profile, material, and application, including custom and hard-to-find sizes. Lot traceability and documentation are available on request.
We make getting O-Rings and hydraulic seals easy.
3 Most Common FAQs
FAQ 1: How do I know if this hydraulic seal will fit my cylinder?
Match the seal ID, OD, and HT to the removed seal or gland. For this part, confirm 0.375"ID, 0.625"OD, and 0.250"HT. Also check rod size, bore size, groove width, groove depth, and the loaded U-Cup profile before ordering.
FAQ 2: Can this seal be used as both a rod seal and piston seal?
This loaded U-Cup may be used in rod or piston applications if the gland design supports the profile and pressure direction. Final use depends on the cylinder design, groove dimensions, and how the seal is energized in the application.
FAQ 3: What information should I provide before ordering?
Provide the seal dimensions, material, fluid type, temperature, pressure, rod or piston use, equipment type, and photos of the old seal if available. Clear measurements reduce wrong-part orders and help us confirm the best replacement.
