ISO 4927:2005 specifies performance tests for moulded rubber boots used at end closures on drum type wheel brake cylinders. These boots prevent the entrance of dirt and moisture which could cause corrosion and otherwise impair wheel brake operation.
ISO 4927:2005 is applicable to boots of both plain and reinforcement insert types, for fitting in wheel cylinders using a fluid in accordance with ISO 4925. It does not include requirements relating to chemical composition, tensile strength or elongation at brake of the rubber compound; it does not cover the strength of adhesion of rubber to the reinforcement in the insert type.
The rubber material used in these boots shall be suitable for operation in a temperature range of -40 °C to +120 °C.