ISO 4930:2006

INTERNATIONAL ISO
STANDARD 4930
Second edition
2006-07-15

Road vehicles — Elastomeric seals for
hydraulic disc brake cylinders using a
non-petroleum base hydraulic brake fluid
(Service temperature 150 °C max.)
Véhicules routiers — Joints en caoutchouc pour cylindres de freins
hydrauliques à disque utilisant un liquide de frein à base non pétrolière
(Température maximale d'utilisation 150 °C)



Reference number
ISO 4930:2006(E)
©
ISO 2006

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ISO 4930:2006(E)
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ISO 4930:2006(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Product requirements. 1
4 Brake test fluid . 1
5 Apparatus . 2
5.1 Apparatus for test of resistance to fluid at elevated temperature, physical stability and
precipitation characteristics. 2
5.2 Apparatus for high-temperature stroking test (see Figure 1) . 2
5.3 Apparatus for low-temperature leakage test (see Figure 2). 3
6 Test requirements. 3
7 Preparation of test specimens . 4
8 Resistance to fluid at elevated temperature . 4
8.1 Test specimens . 4
8.2 Test procedure . 5
9 Resistance to fluid at elevated temperature – Precipitation characteristics. 5
9.1 Test specimens . 5
9.2 Test procedure . 5
10 Resistance to elevated temperature in dry air.6
10.1 Test specimens . 6
10.2 Test procedure . 6
11 Ambient-temperature stroking test. 6
11.1 Test specimens . 6
11.2 Test procedure . 6
12 High-temperature stroking test . 7
12.1 Test specimens . 7
12.2 Test procedure . 7
13 Low-temperature leakage test . 8
13.1 Test specimens . 8
13.2 Test procedure . 8
13.3 Bent test procedure. 9
14 Cycling humidity storage corrosion test. 9
14.1 Test specimens . 9
14.2 Test procedure . 9

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ISO 4930:2006(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 4930 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 2, Braking
systems and equipment.
This second edition cancels and replaces the first edition (ISO 4930:1978), which has been technically revised.

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INTERNATIONAL STANDARD ISO 4930:2006(E)

Road vehicles — Elastomeric seals for hydraulic disc brake
cylinders using a non-petroleum base hydraulic brake fluid
(Service temperature 150 °C max.)
1 Scope
This International Standard specifies the performance test methods and requirements for elastomeric seals
used in road vehicle disc brake cylinders.
It is applicable to solid section type seals (square, rectangular, “O”-ring), mounted stationary in the cylinder
bore or on the movable piston of disc brakes.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 48, Rubber, vulcanized or thermoplastic — Determination of hardness (hardness between 10 IRHD and
100 IRHD)
ISO 188, Rubber, vulcanized or thermoplastic — Accelerated ageing and heat resistance tests
ISO 1817, Rubber, vulcanized — Determination of the effect of liquids
ISO 4926, Road vehicles — Hydraulic brake systems — Non-petroleum base reference fluids
ISO 4928, Road vehicles — Elastomeric cups and seals for cylinders for hydraulic braking systems using a
non-petroleum base hydraulic brake fluid (Service temperature 120 °C max.)
3 Product requirements
Seals shall conform to the pertinent drawing in all respects, and shall be free from blisters, pin-holes, cracks,
protuberances, embedded foreign material, or other physical defects which can be detected by thorough
inspection.
These elastomeric seals shall be suitable for operation in a temperature range of −40 °C to +150 °C.
4 Brake test fluid
The test fluid for all tests except the test specified in Clause 14 shall be compatibility fluid as defined in
ISO 4926. The fluid specified in Clause 14 shall be ISO fluid for storage corrosion test as defined in ISO 4926
or the fluid agreed by the parties concerned.
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ISO 4930:2006(E)
5 Apparatus
5.1 Apparatus for test of resistance to fluid at elevated temperature, physical stability and
precipitation characteristics
5.1.1 Oven, uniformly heated, dry air type conforming to the requirements of ISO 188.
5.1.2 Test jar, screw-top straight-sided round glass type, having a capacity of approximately 250 ml and
inner dimensions of approximately 125 mm height and 50 mm diameter, with a tinned steel lid (no insert or
organic coating).
5.2 Apparatus for high-temperature stroking test (see Figure 1)
5.2.1 Pneumatic or hydraulic pressure source.
5.2.2 Master cylinder.
5.2.3 Pressure gauge.
5.2.4 Wheel cylinder seat stroking fixture.
5.2.5 Cylinder assembly.
5.2.6 Oven, in accordance with 5.1.1.

Key
1 pneumatic or hydraulic pressure source
2 master cylinder
3 pressure gauge
4 wheel cylinder seal stroking fixture
5 oven chamber at +120 °C
6 cylinder assembly
Figure 1 — High-temperature stroking test
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ISO 4930:2006(E)
5.3 Apparatus for low-temperature leakage test (see Figure 2)
5.3.1 Hydraulic pressure gauge.
5.3.2 Master cylinder.
5.3.3 Cylinder assembly.
5.3.4 Cold chamber, at −40 °C.
Dimensions in millimetres

Key
1 hydraulic pressure gauge
2 master cylinder
3 cylinder assembly
4 cold chamber at −40 °C
Figure 2 — Low-temperature leakage test
6 Test requirements
6.1 After the test for resistance to fluid at elevated temperature (physical stability) (see Clause 8), the seals
shall conform to the following requirements:
a) any change in volume shall be within 0 % to +15 %;
b) any change in hardness shall be within 0 IRDH to −15 IRHD.
6.2 After the test for resistance to fluid at elevated temperature (precipitation characteristics) (see Clause 9),
not more than 0,3 % sediment by volume shall be formed in the test fluid used.
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ISO 4930:2006(E)
6.3 After the test for resistance to elevated temperature in dry air (see Clause 10), the seals shall conform
to the following requirements:
a) any change in hardness shall be within 0 IRDH to +15 IRHD;
b) seal condition: test specimens shall show no evidence of blistering, cracking, or change in shape from the
original form.
6.4 After the ambient temperature stroking test (see Clause 11), seals and assembly shall conform to the
following requirements:
a) no leakage beyond normal wetting of the bore(s) shall occur during the stroking test;
b) no leakage beyond normal wetting of the bore(s) shall occur during the static leak test (see 11.2.3).
6.5 After the high temperature stroking test (see Clause 12), the seals and assembly shall conform to the
following requirements:
a) no leakage beyond normal wetting of the bore(s) shall occur during the stroking test;
b) no leakage beyond normal wetting of the bore(s) shall occur during the static leak test (see 12.2.4).
6.6 After the low temperature leakage test (see Clause 13), the seals and assembly shall conform to the
following requirements:
a) no leakage beyond normal wetting of the bore(s) shall occur during the test period or pressure
application;
b) the seal shall not crack, shall remain flexible and shall return to its approximate original shape
...