GB/T 18274-2017 English PDF (GBT18274-2017)

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GB/T 18274-2017: Technical specifications for motor vehicle brake system
GB/T 18274-2017
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 43.040.40
T 24
Replacing GB/T 18274-2000, GB/T 18275.1-2000, GB/T 18275.2-2000,
GB/T 18343-2001
Technical Specifications for
Motor Vehicle Brake System
ISSUED ON. OCTOBER 14, 2017
IMPLEMENTED ON. MAY 01, 2018
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 4
4 Technical Requirements ... 5
5 Inspection Rules ... 18
6 Other ... 18
Appendix A (Normative) Maintenance Reference Data on Brake Disc, Brake
Friction Block for Disc Brake of Common Vehicles ... 19
Foreword
This Standard was drafted as per the rules specified in GB/T 1.1-2009.
This Standard replaced GB/T 18274-2000 Technical Specifications for Motor Vehicle
Drum Brake Being Overhauled, GB/T 18275.1-2000 Specifications for Automobile
Braking Transmission Device Being Overhauled – Air Braking, GB/T 18275.2-2000
Specifications for Automobile Braking Transmission Device Being Overhauled –
Hydraulic Braking, and GB/T 18343-2001 Specification for Automobile Disk Brakes
Being Overhauled; this Standard has the major technical changes as follows besides
the editorial modifications.
--- Add the technical requirements for brake’s parking brake devices (see 4.6);
--- Add the requirements for warranty period of brake maintenance (see 6.2).
This Standard was proposed by Ministry of Transport of the PRC.
This Standard shall be under the jurisdiction of National Technical Committee for
Standardization of Automobile Maintenance (SAC/TC 247).
Drafting organizations of this Standard. Research Institute of Highway of Ministry of
Transport, Hangzhou Changyun Transport Group Co., Ltd., and Zhejiang Institute of
Communication.
Chief drafting staffs of this Standard. Liu Jiannong, Jin Baizheng, Zhu Guojun, Zhao
Jinxiang, Zhan Yuanwu, and Zhang Mingjian.
The historical editions replaced by this Standard are as follows.
--- GB/T 18274-2000;
--- GB/T 18275.1-2000;
--- GB/T 18275.2-2000;
--- GB/T 18343-2001.
Technical Specifications for
Motor Vehicle Brake System
1 Scope
This Standard specifies the technical requirements and test rules for the completion of
disk brake, drum brake, air braking transmission device, hydraulic braking
transmission device and parking brake device being overhauled.
This Standard is applicable to the overhaul of brakes and brake transmission devices
for automobiles and trailers; the overhaul of brakes for other types of vehicles can refer
to.
2 Normative References
The following documents are essential to the application of this document. For the
dated documents, only the versions with the dates indicated are applicable to this
document; for the undated documents, only the latest version (including all the
amendments) are applicable to this document.
GB/T 5624 Motor Vehicle Maintenance and Repair Terms
GB 5763 Brake Linings for Automobiles
GB 7258 Safety Specifications for Motor Vehicles Operating on Roads
3 Terms and Definitions
The following terms and definitions and those ones stipulated in GB/T 5624 are
applicable to this document.
3.1 Safety repair size
The minimum size allowed for cutting after wear of the surface of the friction pair
element in the brake.
4.2.3.2 After wearing, the thickness of the brake friction block of vehicle shall meet
the original technical requirements of the manufacturer; if there is no specified
thickness value, and the value is less than 1.5mm, then it shall be replaced.
4.2.3.3 After wearing, the thickness of brake friction block of large passenger car
shall meet the original technical requirements of the manufacturer; if there is no
specified thickness value, and the value is less than 2.0mm; then it shall be replaced.
4.2.3.4 When the flat groove of the brake friction block is flattened completely, it shall
be replaced.
4.2.3.5 When the brake friction block doesn’t meet the original technical
requirements of the manufacturer; the wheels on both sides of the coaxial shaft must
be replaced at the same time.
4.2.3.6 When installing, it shall be kept clean and dry. For floating caliper brake, after
installing the internal friction block, check that the dirt-proof boot not to contact with the
brake friction block.
4.2.4 Maintenance data
4.2.4.1 The maintenance reference data of the common brake disc and brake friction
block of the vehicles can see Table A.1.
4.2.4.2 The maintenance reference data of the common brake disc and brake friction
block of the large passenger car can see Table A.2.
4.3 Drum brake
4.3.1 Brake drum
4.3.1.1 The brake drum shall be replaced timely in the following cases.
a) Measure the amount of wear of the brake drum at both the narrow and wide sides
of the friction surfaces at right angles to each other; measure the diameter of the
brake drum at every 45° point on the circumference and at the bottom of deepest
groove; when the diameter of brake drum exceeds the rejection size or although
it is not exceeding the rejection size, after the cutting process, its diameter
exceed the safe repair size;
b) The cylindricity error of the brake drum friction surface shall be no greater than
0.05mm; the roundness error shall be no greater than 0.155mm; surface
roughness shall be no less than Ra1.6; the radical run-out of the cylinder surface
and the plane combined the friction surface of the brake drum with the hub shall
be no greater than 0.10mm; the wall thickness difference of the brake drum shall
be no greater than 1.00mm; the diameter difference between he right and left
4.4.1.4 After repairing, the air compressor shall be worn out according to the wearing
specification; the post-repairing air compressor shall meet the original technical
requirements of the manufacturer.
4.4.2 Brake valve
4.4.2.1 Brake valve parts
The brake valve parts shall be replaced timely in the following cases.
a) When the diaphragm, valve rubber, seal ring have deformation, crack or aging
phenomena;
b) When the valve or valve seat have scratches, dents or excessive wear;
c) When brake valve housing and valve cover have cracks, deformations and
defects;
d) When the elasticity of balance spring and return spring of brake valve doesn’t
meet the original technical requirements of the manufacturer.
4.4.2.2 Assembly and adjustment of brake valves
4.4.2.2.1 The preload of the balance spring shall meet the original technical
requirements of the manufacturer; after the balance spring is assembled, both ends of
the balance spring shall be perpendicular to its central axis; the permissible error shall
not exceed 2°.
4.4.2.2.2 Before the intake valve is assembled, check the distance between the
intake valve seat and the end of valve stem, which shall meet the original technical
requirements of the manufacturer.
4.4.2.2.3 The distance between end face of the exhaust valve housing and the end
of the valve stem shall meet the original technical requirements of the manufacturer.
4.4.2.2.4 The free stroke of the brake valve pull arm shall be adjusted to 1mm~3mm;
the maximum stroke of the brake pedal shall ensure the stable working air pressure of
the brake air chamber.
4.4.2.3 Inspection of sealing performance of brake valve
4.4.2.3.1 The brake valve is in the de-braking state; under the ...