GMNA - GM6403M
Hydraulic Brake Hose Assembly
|Publication Date:||1 May 2014|
This specification defines the requirements for hydraulic brake (jounce) hose assemblies. This hose assembly is suitable for use at temperatures of -40 to 100 oC, and operating pressures of 17.2 MPa.
Inner Tube. The inner tube of the hose shall consist of a smooth inner rubber tube of ethylene propylene diene monomer (EPDM), or a blend of ethylene propylene diene monomer and isobuteneisoprene rubber (EPDM-IIR). There shall be no materials in the tube compound extractable through exposure to either DOT 3 or DOT 4 brake fluids, as evidenced by 0 or positive values for volume change when the hose is tested to the requirements of Section 188.8.131.52 for each of the two fluids, DOT 3 and DOT 4.
Reinforcement. The reinforcement for the hose shall consist of two layers of polyvinyl alcohol (PVA). A rubber cushion liner may be placed between the two layers of PVA.
Cover. The outer cover of the hose shall consist of a layer of ethylene propylene diene monomer (EPDM).
Coupling Design. The coupling shall be designed, inserted, swaged or crimped so that no internal tube abrasions, cuts or flaws shall result under any condition or combination of assembly component dimensioning or tolerancing allowed by supplier production specifications, or under any condition of rubber hose compression allowed by supplier production specifications.
Sharp Corners. Sharp corners shall be avoided where the coupling contacts the tube to prevent cutting of the hose when subjected to internal pressure.
Tube Insert. The tube insert must not extend past the end of the crimp shell after crimping, and the end of the tube insert must be radiused to eliminate burrs or sharp edges which might cause hose damage under conditions of assembly vibration or pressure impulse.
Damage. Damage to hose rubber or reinforcement generated by the crimping of the hose is not permissible under any possible production manufacturing conditions or supplier production tolerance stack-up, including variations in hose compression concentricity.
Tube Collapse. Metal tube insert collapse during crimping is not permissible, except when this collapse is limited, predictable, controllable, and does not increase the potential for assembly leakage or other malfunction.
Design Restrictions. Grooves, upsets, or serrations are not permitted on the tube stem OD, or on the crimp shell ID, except that these grooves, upsets, or serrations do not cause hose cutting or other damage under any condition or combination of assembly component dimensioning or tolerancing allowed by supplier production specifications, or under any condition of rubber hose compression allowed by supplier production specifications.
Skiving, Adhesives. Skiving of the hose is not permissible. Use of adhesives in the crimped joint is not permissible.
Flow Requirements. The coupling shall be designed for low flow restriction.