High Pressure Hydraulic Cylinder Seals – Piston, Rod & Wiper Seals

High Pressure Hydraulic Cylinder Seals – Piston, Rod & Wiper Seals

Kaybin manufactures hydraulic cylinder seals including piston seals, rod seals, U-cups, buffer seals and wiper/scraper seals engineered for high-pressure industrial and mobile hydraulic systems.

These reciprocating seals are moulded or machined to your groove dimensions, pressure class and duty cycle to control leakage, resist extrusion and extend cylinder service life in mining, press, mobile and OEM equipment across South Africa and Africa.

This page covers reciprocating hydraulic and pneumatic cylinder seals only — not rotary shaft seals, O-rings or Chevron packing.

Seal Family Segmentation

Piston Seals
Single-acting and double-acting piston seals used to separate pressure chambers within hydraulic cylinders.

Rod Seals
Primary dynamic seals installed in the gland to prevent external leakage from the cylinder.

Buffer Seals
Secondary pressure-control elements positioned ahead of rod seals to absorb pressure spikes and reduce load on the primary seal.

U-Cup Seals
Symmetrical and asymmetrical lip profiles for dynamic sealing in piston or rod applications.

Wiper / Scraper Seals
Installed externally to exclude dust, slurry and water from entering the cylinder and damaging internal components.

Compact Seals
Integrated multi-element sealing systems used in higher-pressure hydraulic cylinders where space is limited and performance demands are elevated.

Material Segmentation

Polyurethane (PU)

• High wear resistance
• Strong extrusion resistance
• Common in mining and heavy-duty hydraulic service

Rubber-Based Compounds

• NBR – mineral oil hydraulic systems
• HNBR – elevated temperature and enhanced oil resistance
• EPDM – water-based fluids (not compatible with mineral oils)
• FKM / Viton® – aggressive fluids and higher temperatures
• Silicone – wide temperature range applications

PTFE & Filled PTFE

• Low friction characteristics
• Reduced stick-slip behaviour
• Chemical resistance
• Often combined with energisers or back-up rings

Material hardness (Shore A) and profile geometry are selected based on pressure, temperature, rod speed, contamination level and extrusion gap.

Performance & Engineering Considerations

Hydraulic cylinder seals are designed for:

• High-pressure hydraulic circuits
• Reciprocating motion under load
• Side-load and shock loading conditions
• Mining, mobile and industrial duty environments

Critical specification factors include:

• Extrusion gap control
• Groove tolerance and gland design
• Surface finish (Ra) compatibility
• Rod hardness
• Seal squeeze and radial interference
• Pressure spikes and shock loading
• Dynamic vs static friction behaviour

Cylinder Seal Specification Checklist

Common Failure Modes Addressed

Correctly specified hydraulic cylinder seals help prevent:

• Seal extrusion into clearance gaps
• Nibbling and edge damage
• Spiral failure
• Lip rollover
• Compression set
• Rod scoring
• Internal bypass leakage
• Seal hardening due to thermal exposure

Seal profile, compound selection and gland compatibility are reviewed prior to manufacture to reduce premature failure.

Hydraulic Seal Kits & Replacement Support

Kaybin supplies:

• Hydraulic cylinder seal kits
• Rod seal replacement kits
• Piston seal replacement kits
• Custom seal stacks
• Reverse-engineered seal kits for discontinued OEM cylinders

Custom hydraulic sealing solutions manufactured to specification for reliable performance in industrial and mobile hydraulic systems across Africa.