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Push-on forces for automotive coolant hoses are the single largest assembly consideration with hose clamped coolant joints. The force required to push the hose to its' proper design location varies with hose, bead and fitting design. This paper deals exclusively with push-on forces for automotive coolant hoses. Factors affecting push-on forces along with the effect of hose interference, material, construction, mandrel size and lubrication will be evaluated. The intent is to understand how joint design parameters affect push-on forces and how to reduce the force required to assemble the joint without sacrificing joint integrity.

This paper will deal exclusively with automotive coolant leaks caused by improper joint design. It is intended to help prevent frequent design errors by using variation reduction tools. A systems approach to sealing coolant carrying joints fastened with hose clamps has been adopted. The systems method looks at each component in the joint and its relative importance to the systems sealability. Revised dimensioning, machining, and assembly practices have been recommended to remove joint to joint variation. Successful implementation of spring clamp technology (continuous force clamps) has, in some cases, eliminated the need for conventional screw type clamps. However, adjustable clamps requiring a torque specification (i.e. worm gear, double wire, etc.) may be still required for special applications. More design and validation guidelines can be found in SAE Recommended Practices Document J1697.