Oil Seals

An oil film around a shaft, the crankshaft end or the gear selector can be a sign of a worn oil seal. We bring together oil seals in fixed millimetre sizes and model-specific versions for engines, transmissions and axles, so you can stop the leak with the right seal.

What does an oil seal do?

An oil seal seals where a rotating shaft passes through a housing. It keeps the oil in and dirt out. Typically, a rubber lip with a spring presses lightly against the shaft surface. This category includes both universal seals in millimetre sizes, e.g. Cometic 14X22X6 Oil Seal, and model-specific parts such as Ford Racing 302 One Piece Rear Main Oil Seal and Omix Inner Axle Oil Seal for Jeep. For specific locations, you can also see crankshaft seals and camshaft oil seals.

How to choose the right oil seal

• Size: inner diameter, outer diameter and width, e.g. 14x22x5 or 14x22x6. One millimetre in width can determine whether the seal sits correctly in the housing.
• Model and year: model-specific seals from KYB Powersports are listed for e.g. Yamaha YZ and Kawasaki KX85 within specific model years. Check them against your vehicle.
• Quantity: some items are sold in 10-packs, which can be a good fit if you service several vehicles.

Universal sizes are available from, among others, Cometic Gasket. If the whole front fork needs rebuilding, complete fork seal kits are available.

Installation and typical faults

Clean the housing and the shaft surface, and check for grooves from the old lip. A worn shaft can make even a new seal leak. Lightly lubricate the lip with oil, face it towards the oil, and press the seal in straight using a suitable tool. Crooked installation or a damaged lip are typical causes of new leaks.

Frequently asked questions

How do I read the sizes on an oil seal?

A size such as 14x22x6 typically indicates inner diameter, outer diameter and width in millimetres. Measure the old seal or the shaft and housing, and compare with the stated dimensions for the specific part number.

Can I reuse an oil seal?

It is typically not recommended. The lip adapts to the shaft surface during use and can be damaged during removal, so a new seal gives the best chance of a tight joint.

Why is a newly replaced oil seal leaking?

The cause can be a grooved shaft surface, crooked installation, a lip facing the wrong way or the wrong size. High crankcase pressure, e.g. from a clogged breather, can also push oil past.