// Catalogue

Seals, Gaskets & O-Rings: Hydraulic O-Rings, Bonded Seals and Seal Kits

Seals, gaskets & O-rings keep oil in and dirt out at every joint, port and shaft. TSA Hydraulics Engineering supplies them within the Sensors & Switches family of our Motors & Drives range, alongside Pressure Sensors, Temperature Sensors, Flow Sensors, Condition Monitoring, and Hoses, Pipes & Fittings.

Measure the groove, not the old seal. A seal that has spent years in hot oil has swollen, shrunk or taken a set, so copying it gives the wrong size. Match the groove, the fluid and the temperature first, then the hardness. Send the part number, kit code or groove sizes, and we’ll match genuine or equivalent seals.

// Buying guide

Types of Seal

O-rings: the everyday static and light dynamic seal, in metric and imperial sizes.
Backup rings: stop O-rings squeezing out of the groove at high pressure.
Bonded seals: a metal washer with a rubber lip, used on parallel thread fittings.
Rod and piston seals: keep cylinders sealed as they stroke.
Wipers: stop dirt being dragged into a cylinder on the rod.
Shaft seals: lip seals that keep oil in around rotating shafts.
Flange gaskets and seals: for SAE flanges, covers and housings.
Seal kits: complete sets for a specific cylinder, valve, flow meter or other component.

Choosing the Material

Nitrile (NBR): the standard for mineral hydraulic oil, roughly minus 30 to plus 100 °C.
FKM (Viton type): for higher temperatures and many fire resistant and synthetic fluids.
EPDM: for water, glycol and phosphate ester fluids. Never use it with mineral oil.
HNBR: tougher than nitrile, and better in heat.
Polyurethane: very wear resistant, and common in rod seals and wipers.
PTFE: low friction, for backup rings and high speed seals.

The wrong material can swell, soften or crack within weeks, even if the size is perfect.

Hardness and Pressure

Most hydraulic O-rings are 70 or 90 Shore A. Harder seals resist extrusion at high pressure, while softer ones seal better at low pressure. Above about 100 to 150 bar, or where the gaps are large, add backup rings.

Fitting Seals Properly

Clean the groove and check for burrs and sharp edges.
Lubricate seals with the system oil before fitting.
Cover threads and sharp edges with a fitting sleeve or tape.
Don’t over stretch O-rings or roll them into place.
Replace every seal you disturb, not just the one that leaked.

What a Failed Seal Tells You

Nibbled or chewed edges: extrusion from high pressure or a large gap.
Hard and cracked: too much heat.
Swollen or soft: the wrong material for the fluid.
Cuts and nicks: damage during fitting.
Flat on one side: compression set from age or heat.

Matching the cause stops the same leak coming back, and condition monitoring often shows it before the next seal goes.

Building a Seal Stock

An O-ring assortment in nitrile and FKM, in metric and imperial sizes.
Bonded seals for the fitting sizes you use most.
Seal kits for each critical cylinder and valve.
A few spare wipers and rod seals for machines that work in dirt.

Seals, Gaskets & O-Rings Specifications to Check

Inside diameter and cross section, or groove sizes
Material and hardness
Fluid compatibility
Temperature range
Pressure and any need for backup rings
Metric or imperial standard sizing

Why Buy From TSA Hydraulics Engineering

As a seals, gaskets & O-rings supplier, we match the size, material and hardness to your fluid and temperature, not just the old part. You get clear prices in AUD, OEM or equivalent options, and help sourcing seals, gaskets & O-rings replacement parts such as complete seal kits and assortment boxes. We tell you upfront whether a part is genuine or an equivalent.

// FAQs