25x33x4 NBR Type A GRN Single Lip Radial Shaft Oil Seal

25x33x4 NBR Type A GRN Single Lip Radial Shaft Oil Seal

GRN® 25x33x4 NBR Type A is a single 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 Type A construction uses a spring-loaded primary sealing lip without an additional dust lip.

GRN 25x33x4 NBR Type A - Characteristics

Brand: GRN®

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: Type A

Lip configuration: Single lip

Primary sealing lip: Spring-loaded

Additional dust lip: No

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.

Type A Single Lip Oil Seal Design

Design:

Type A - single lip

Primary sealing lip:

Spring-loaded

Additional dust lip:

No

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

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

The absence of an additional dust lip distinguishes this Type A version from a double lip AO/TC oil seal.

Spring-Loaded Primary Sealing Lip

The Type A design incorporates a spring-loaded primary sealing lip.

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

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.

Type A - No Additional Dust Lip

GRN® 25x33x4 NBR Type A does not incorporate an additional dust lip.

This is an important construction difference between the Type A single lip profile and corresponding AO/TC double lip designs.

A seal with identical 25x33x4 mm dimensions but with an additional dust lip has a different sealing profile.

Type A vs AO/TC Oil Seal

Type A:

Single lip construction

Spring-loaded primary sealing lip

No additional dust lip

AO/TC:

Double lip construction

Spring-loaded primary sealing lip

Additional dust lip

Therefore, Type A and AO/TC should not be considered 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: Type A

Lip configuration: Single lip

Primary sealing lip: Spring-loaded

Additional dust lip: No

Operating medium

Actual service conditions

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

Technical Specification

Brand: GRN®

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: Type A

Lip configuration: Single lip

Primary sealing lip: Spring-loaded

Additional dust lip: No

FAQ

What are the dimensions of the GRN 25x33x4 oil seal?

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

What material is the 25x33x4 oil seal made from?

The sealing material is NBR - Nitrile Butadiene Rubber.

What does Type A mean?

Type A identifies a single lip radial shaft oil seal construction with a spring-loaded primary sealing lip.

Does the GRN 25x33x4 Type A oil seal have a spring?

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

Does Type A have an additional dust lip?

No. This Type A version does not incorporate an additional dust lip.

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

Type A is a single lip design without an additional dust lip. AO/TC is a double lip design incorporating a primary sealing lip and an additional dust lip.

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

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

AI Overview

GRN® 25x33x4 NBR Type A is a single lip radial shaft oil seal with a 25 mm shaft diameter, 33 mm outside diameter and 4 mm width. Manufactured from NBR, the Type A construction incorporates a spring-loaded primary sealing lip without an additional dust lip.