ISO 7633:1985 PDF

Road vehicles — Elastomeric boots for drum type hydraulic brake wheel cylinders using a petroleum base hydraulic brake fluid (service temperature 120 degrees C max.)

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Title (English):

ISO 7633:1985

Road vehicles — Elastomeric boots for drum type hydraulic brake wheel cylinders using a petroleum base hydraulic brake fluid (service temperature 120 degrees C max.)

Document status:: Active
Format:: Electronic (PDF)
Number of pages:: 4
Publication date:: July 25, 1985
Edition:: ISO IS 7633 edition 1 version 1
ICS:: 43.040.40

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Description (English):

Specifies performance tests for moulded rubber boots used as end closures on drum type brake cylinders. These boots prevent the entrance of dirt and moisture which could cause corrosion and otherwise impair wheel brake operation. Applies to boots of both plain and reinforcement insert types. Requirements relating to chemical composition, tensile strength or elongation at break of the rubber compound are not included.

Technical details

Technical committee: ISO/TC 22/SC 33 - Vehicle dynamics and chassis components
SKU: ISO 7633:1985

Abstract

Overview

ISO 7633:1985 specifies performance test methods for moulded elastomeric boots (end closures) used on drum‑type hydraulic brake wheel cylinders that operate with a petroleum‑based hydraulic brake fluid (service temperature up to 120 °C). The standard covers both plain and reinforced boots and focuses on functional performance (aging, dimensional stability, sealing and resistance to ozone and fluids). It does not set requirements for rubber chemical composition, tensile strength or elongation at break.

Key topics and requirements

Scope and identification
- Applies to boots for drum‑type wheel cylinders using petroleum‑based fluid (ISO 7309 reference).
- Boots must be free from visible defects (blisters, cracks, inclusions) and conform to drawing dimensions.
- Boots intended for petroleum‑based fluids must carry a green identification mark (ink or colored elastomer) and may be molded with the manufacturer’s marking and “ISO 7633”.
Service temperature
- Elastomer designed for −40 °C to +120 °C operation.
Performance tests (examples)
- High‑temperature liquid resistance: Immersion in reference petroleum brake fluid and exposure to 120 ± 2 °C; acceptable volume change: −10% to +20%; hardness change: −10 to +10 DIDC.
- High‑temperature displacement (dynamic): Boots mounted on cylinder, actuated (1 000 piston strokes/h, stroke 4.75 ± 0.25 mm) while exposed to 120 ± 2 °C for specified duration; boots must not crack and must remain in contact with cylinder and piston rod.
- Low‑temperature displacement: Exposure at −40 to −43 °C with cyclical piston strokes; boots must remain crack‑free and retain contact.
- Heat resistance (static): Oven aging at 120 ± 2 °C (22 h); boots must show no cracks when flexed, hardness change within −5 to +10 DIDC, and not be tacky.
- Tensile/retention test: Mandrel expansion to simulate stretch; permanent set after test must not exceed specified limit (relative permanent elongation ≤ 75%).
- Ozone resistance: Exposure to 50 ± 5 pphm ozone at 40 ± 2 °C for 70 ± 2 h; samples inspected for surface cracking (no cracks allowed).
Referenced test equipment/standards
- Uses apparatus and methods referenced in ISO 48 (hardness), ISO 188 (aging ovens), ISO 1431 (ozone), ISO 7309 (reference fluid), ISO 4927/4928 (related boot/cup tests).

Applications and users

ISO 7633 is used by:

Automotive OEMs and tier‑1 brake component manufacturers for design verification and supplier acceptance.
Quality control and testing laboratories to validate boot performance under thermal, chemical and ozone stress.
Materials and sealing engineers selecting elastomers for brake cylinder applications.
Regulatory and procurement teams specifying component conformity and identification.

Practical benefits include improved durability, reliable sealing against dirt and moisture, and consistent field performance of drum‑type hydraulic brakes.

Related standards

ISO 7309 - reference petroleum brake fluid
ISO 4927 / ISO 4928 - related rubber cups and displacement test methods
ISO 48 - hardness testing of vulcanized elastomers
ISO 188 - accelerated aging ovens
ISO 1431 - ozone resistance testing

Keywords: ISO 7633:1985, elastomeric boots, drum type hydraulic brake wheel cylinders, petroleum base hydraulic brake fluid, brake boot testing, ozone resistance, high temperature displacement, automotive brake components.

Related standards

Standards mentioned in the description

Abstract

Overview

Key topics and requirements

Scope and identification
- Applies to boots for drum‑type wheel cylinders using petroleum‑based fluid (ISO 7309 reference).
- Boots must be free from visible defects (blisters, cracks, inclusions) and conform to drawing dimensions.
- Boots intended for petroleum‑based fluids must carry a green identification mark (ink or colored elastomer) and may be molded with the manufacturer’s marking and “ISO 7633”.
Service temperature
- Elastomer designed for −40 °C to +120 °C operation.
Performance tests (examples)
- High‑temperature liquid resistance: Immersion in reference petroleum brake fluid and exposure to 120 ± 2 °C; acceptable volume change: −10% to +20%; hardness change: −10 to +10 DIDC.
- High‑temperature displacement (dynamic): Boots mounted on cylinder, actuated (1 000 piston strokes/h, stroke 4.75 ± 0.25 mm) while exposed to 120 ± 2 °C for specified duration; boots must not crack and must remain in contact with cylinder and piston rod.
- Low‑temperature displacement: Exposure at −40 to −43 °C with cyclical piston strokes; boots must remain crack‑free and retain contact.
- Heat resistance (static): Oven aging at 120 ± 2 °C (22 h); boots must show no cracks when flexed, hardness change within −5 to +10 DIDC, and not be tacky.
- Tensile/retention test: Mandrel expansion to simulate stretch; permanent set after test must not exceed specified limit (relative permanent elongation ≤ 75%).
- Ozone resistance: Exposure to 50 ± 5 pphm ozone at 40 ± 2 °C for 70 ± 2 h; samples inspected for surface cracking (no cracks allowed).
Referenced test equipment/standards
- Uses apparatus and methods referenced in ISO 48 (hardness), ISO 188 (aging ovens), ISO 1431 (ozone), ISO 7309 (reference fluid), ISO 4927/4928 (related boot/cup tests).

Applications and users

ISO 7633 is used by:

Automotive OEMs and tier‑1 brake component manufacturers for design verification and supplier acceptance.
Quality control and testing laboratories to validate boot performance under thermal, chemical and ozone stress.
Materials and sealing engineers selecting elastomers for brake cylinder applications.
Regulatory and procurement teams specifying component conformity and identification.

Practical benefits include improved durability, reliable sealing against dirt and moisture, and consistent field performance of drum‑type hydraulic brakes.

Related standards

ISO 7309 - reference petroleum brake fluid
ISO 4927 / ISO 4928 - related rubber cups and displacement test methods
ISO 48 - hardness testing of vulcanized elastomers
ISO 188 - accelerated aging ovens
ISO 1431 - ozone resistance testing

ISO 7633:1985 PDF

Technical details

Abstract

Overview

Key topics and requirements

Applications and users

Related standards

Related standards

Abstract

Overview

Key topics and requirements

Applications and users

Related standards

Related standards

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