ISO 7631-1985 PDF

Full title and description

ISO 7631:1985 — Road vehicles — Elastomeric cups and seals for cylinders for hydraulic braking systems using a petroleum base hydraulic brake fluid (service temperature 120 °C max.). This international standard specifies performance test methods for moulded rubber cups and double‑lipped gland seals used in hydraulic brake cylinders operating with petroleum‑base brake fluids; it does not set requirements for rubber compound composition, tensile strength or elongation, and excludes disc‑brake seals and O‑rings for wheel cylinders.

Abstract

Specifies performance test procedures and service‑temperature criteria (maximum 120 °C) for high‑temperature‑resistant elastomeric cups and seals (moulded cups or double‑lipped seals) intended for hydraulic braking cylinders using petroleum‑base brake fluids. The standard applies to seals of diameter 60 mm or less and excludes requirements on material composition and certain seal types.

General information

• Status: Published (International Standard, confirmed stage 90.93).
• Publication date: May 1985 (1985-05).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 43.040.40 (Braking systems); 83.140.50.
• Edition / version: Edition 1 (1985).
• Number of pages: 11.

Basic bibliographic and lifecycle details as recorded by ISO.

Scope

Applies to moulded elastomeric cups and double‑lipped gland seals made from high‑temperature‑resistant rubber for use in hydraulic brake cylinders that operate with petroleum‑base hydraulic brake fluids (service temperature up to 120 °C). The standard covers performance test methods and limits but does not prescribe rubber compound chemical composition, tensile strength or elongation. It is limited to seals of diameter 60 mm or less and specifically excludes seals for disc brakes and O‑rings for wheel cylinders. The standard references the applicable petroleum‑base brake fluid specification (ISO reference fluid) used in tests.

Key topics and requirements

• Performance test methods for elastomeric cups and double‑lipped gland seals for hydraulic brake cylinders (endurance, leakage, dimensional stability under test conditions).
• Service temperature limit: tested for use up to 120 °C maximum.
• Applicability restricted to moulded seals with nominal diameter ≤ 60 mm.
• Exclusions: no requirements in this standard for chemical composition, tensile strength or elongation of the rubber compound; disc‑brake seals and wheel cylinder O‑rings are excluded.
• Test fluids and references: intended to be used with petroleum‑base hydraulic brake fluids referenced by ISO (see ISO 7308 and related fluid specifications).

Typical use and users

Primary users are automotive component manufacturers, OEMs and suppliers of brake‑system elastomeric seals, laboratory and QA/test houses that perform qualification and batch testing of seal components, and engineering teams specifying brake‑system parts. The standard is used when verifying seal performance in hydraulic brake cylinders that use petroleum‑base fluids and when ensuring compatibility with the referenced test fluid.

Related standards

Closely related documents include fluid and braking‑system standards such as ISO 7308 (petroleum‑based brake‑fluid specifications) and other ISO standards on braking system components and test methods published in the same era (ISO series for road‑vehicle braking systems). Users often consult ISO 7308 when selecting the reference test fluid for ISO 7631 tests.

Keywords

brake seals; elastomeric cups; hydraulic braking systems; petroleum‑base brake fluid; ISO 7631; performance tests; high‑temperature rubber; cylinder seals; brake component testing.

FAQ

Q: What is this standard?

A: ISO 7631:1985 is an international standard that specifies performance test methods for elastomeric cups and double‑lipped seals used in hydraulic brake cylinders that operate with petroleum‑base hydraulic brake fluid (service temperature up to 120 °C).

Q: What does it cover?

A: It covers test procedures and performance criteria for moulded rubber cups and gland seals (≤ 60 mm diameter) used in hydraulic braking cylinders; it does not set material composition, tensile strength or elongation requirements, and it excludes disc‑brake seals and wheel‑cylinder O‑rings.

Q: Who typically uses it?

A: Brake component manufacturers and suppliers, vehicle OEMs, test laboratories, and quality/engineering teams responsible for specifying and validating elastomeric seal performance in petroleum‑base hydraulic brake systems.

Q: Is it current or superseded?

A: ISO's record shows ISO 7631:1985 as published and confirmed through periodic reviews; users should check with the standards body or national mirror for any more recent amendments or replacements before relying on it for procurement or certification.

Q: Is it part of a series?

A: ISO 7631 was published in the mid‑1980s alongside other vehicle/brake related ISO publications (neighboring numbers in the ISO 7600–7640 range cover related braking and diagnostic topics); related fluid specifications such as ISO 7308 are commonly referenced for test fluids.

Q: What are the key keywords?

A: Elastomeric cups, sealing rings, hydraulic brake cylinders, petroleum‑base brake fluid, performance tests, high‑temperature rubber, ISO 7631.