Overview
ISO 9128:2006 defines the graphical symbols and colours used on road vehicles to designate the correct brake fluid type. The standard aims to prevent the use of incompatible fluids (petroleum‑based vs non‑petroleum) that can cause catastrophic brake system failure. It applies to vehicle labelling and under‑bonnet identification of brake fluid reservoirs.
Key points: durable markings, clear placement near the filler cap, and standardised colour/symbol combinations for each fluid type.
Key Topics
Applications
This standard is practical for: vehicle manufacturers, service and maintenance technicians, parts suppliers, and safety auditors. Practical applications include:
- Labelling reservoir caps and adjacent under‑bonnet surfaces to ensure correct brake fluid selection during servicing.
- Marking replacement fluid containers and service documentation to match vehicle markings (the same symbols are used for fluid containers as referenced in ISO 3871).
- Training materials and workshop procedures to reduce the risk of incompatible mixing and subsequent brake failure.
Benefits:
- Reduces risk of catastrophic brake system failure by preventing incorrect fluid use.
- Improves consistency of vehicle and container labelling internationally.
- Supports clear communication between manufacturers, technicians and end users.
Related Standards
- ISO 3871 - Labelling of containers for brake fluids (same symbols may be used on containers).
- ISO 4925 - Specifications for non‑petroleum (glycol) brake fluids.
- ISO 7308 - Petroleum‑based brake fluid for stored‑energy hydraulic brakes.
For implementers, follow ISO 9128:2006 when designing under‑bonnet markings and ensure durable, legible placement close to the filler cap to comply with the minimum dimensions and colour/symbol definitions.