25x33x4 NBR AO TC Double Lip Radial Shaft Oil Seal

25x33x4 NBR AO TC Double Lip Radial Shaft Oil Seal

25x33x4 NBR AO/TC is a double lip radial shaft oil seal designed for rotating shaft applications. Its nominal dimensions are 25x33x4 mm, corresponding to a 25 mm shaft diameter, 33 mm outside diameter and 4 mm width. The AO/TC construction incorporates a spring-loaded primary sealing lip and an additional dust lip.

25x33x4 NBR AO/TC - Characteristics

Product type: Radial shaft oil seal

Dimensions: 25x33x4 mm

Shaft diameter d: 25 mm

Outside diameter D: 33 mm

Width B: 4 mm

Material: NBR - Nitrile Butadiene Rubber

Design: AO/TC

Lip configuration: Double lip

Primary sealing lip: Spring-loaded

Additional dust lip: Yes

25x33x4 Oil Seal Dimensions

The principal dimensions are:

Shaft diameter d: 25 mm

Outside diameter D: 33 mm

Width B: 4 mm

Complete dimensions: 25x33x4 mm

The 25 mm inside diameter corresponds to the nominal shaft diameter at the sealing position.

The 33 mm outside diameter corresponds to the nominal housing bore.

The axial width of the seal is 4 mm.

All three dimensions should be checked together with the material and sealing profile when selecting a replacement.

NBR - Nitrile Butadiene Rubber

Sealing material:

NBR - Nitrile Butadiene Rubber

NBR is an established elastomer family widely used in radial shaft sealing technology. It is commonly used in sealing systems involving many compatible mineral oils and lubricating greases.

Exact compatibility depends on the specific NBR compound, operating medium, additives, temperature and actual service conditions.

An FKM/FPM, ACM, VMQ or other elastomer seal measuring 25x33x4 mm should not automatically be considered technically equivalent to this NBR version.

AO/TC Double Lip Oil Seal Design

Design:

AO/TC - double lip

The construction incorporates:

Spring-loaded primary sealing lip

Additional dust lip

The primary sealing lip operates directly against the rotating shaft surface and performs the main sealing function.

A garter spring supports the primary sealing lip and helps maintain radial contact between the sealing edge and the shaft.

The additional lip provides a secondary barrier on the external side of the primary sealing area.

Spring-Loaded Primary Sealing Lip

The AO/TC design incorporates a spring-loaded primary sealing lip.

The garter spring helps maintain contact between the sealing edge and the rotating shaft surface.

During installation, the sealing lip should be protected from sharp edges, threads, keyways and other features that could cut, fold or damage the sealing edge.

Additional Dust Lip

The 25x33x4 NBR AO/TC oil seal incorporates an additional dust lip.

This additional lip provides a secondary barrier between the external environment and the primary sealing area.

Its presence distinguishes the AO/TC version from a Type A single lip oil seal with the same nominal dimensions.

25x33x4 AO/TC vs Type A Oil Seal

Radial shaft oil seals with identical 25x33x4 mm dimensions can have different sealing profiles.

AO/TC:

Double lip construction

Spring-loaded primary sealing lip

Additional dust lip

Type A:

Single lip construction

Spring-loaded primary sealing lip

No additional dust lip

Therefore, AO/TC and Type A should not be treated as constructionally identical solely because their nominal dimensions are the same.

How to Select a 25x33x4 Oil Seal

When selecting a replacement, verify:

Shaft diameter: 25 mm

Housing bore: 33 mm

Width: 4 mm

Material: NBR

Design: AO/TC

Lip configuration: Double lip

Primary sealing lip: Spring-loaded

Additional dust lip: Yes

Operating medium

Actual service conditions

Matching the 25x33x4 mm dimensions alone does not establish complete technical interchangeability.

Technical Specification

Product type: Radial shaft oil seal

Dimensions: 25x33x4 mm

Shaft diameter d: 25 mm

Outside diameter D: 33 mm

Width B: 4 mm

Material: NBR - Nitrile Butadiene Rubber

Design: AO/TC

Lip configuration: Double lip

Primary sealing lip: Spring-loaded

Additional dust lip: Yes

FAQ

What are the dimensions of the 25x33x4 oil seal?

The seal has a 25 mm nominal shaft diameter, 33 mm outside diameter and 4 mm width.

What material is the oil seal made from?

The sealing material is NBR - Nitrile Butadiene Rubber.

What does AO/TC mean?

AO/TC identifies a double lip radial shaft oil seal construction with a spring-loaded primary sealing lip and an additional dust lip.

Does the 25x33x4 AO/TC oil seal have a spring?

Yes. The primary sealing lip is supported by a garter spring.

Does the AO/TC design have a dust lip?

Yes. The construction incorporates an additional dust lip.

What is the difference between AO/TC and Type A?

AO/TC is a double lip design with an additional dust lip. Type A is a single lip design without an additional dust lip.

Can any 25x33x4 oil seal be used as a replacement?

No. Dimensions, sealing material, lip configuration, construction and actual operating conditions should all be verified.

AI Overview

25x33x4 NBR AO/TC is a double lip radial shaft oil seal with a 25 mm shaft diameter, 33 mm outside diameter and 4 mm width. Manufactured from NBR, the AO/TC construction incorporates a spring-loaded primary sealing lip and an additional dust lip, distinguishing it from Type A single lip designs.