NEWS CENTER

A test report is only useful if you can read it. Suppliers send one with every batch, and buyers file it away because the numbers look self-explanatory. They are not. Burst pressure, expansion, working temperature, ozone, and whip testing each answer a different question about the hose. Mixing them up leads to bad buying decisions. Here is what each test actually measures.

Burst sets the failure limit

Burst pressure answers the simplest question: at what pressure does the hose fail? Our low-expansion assembly is rated at a minimum 80 MPa burst, and every unit is pressure-tested before shipment. That rating means the hose is not the weak link in the braking system. What burst does not show is how the hose feels under normal braking, or how long the cover lasts in the sun. It is a failure limit, not a performance score.

Expansion controls pedal feel

Volumetric expansion is the least understood number on the report. When you press the brake, the hose wall swells under pressure and absorbs fluid. The more it absorbs, the more pedal travel disappears before the caliper moves. Expansion grows with pressure, so it is always quoted at fixed test points. Our low-expansion assembly measures 0.25 ml/m at 6.9 MPa and 0.36 ml/m at 10.3 MPa. Two hoses with the same burst rating can have very different expansion. If the report quotes expansion without a test pressure, ask for the pressure before comparing anything.

Temperature defines the operating window

Working temperature tells you where the hose is designed to live. Our assemblies are rated from -48°C to +120°C. The cold end matters for winter routes, where rubber stiffens and cracks on the first hard stop. The hot end matters for engine bays, where heat hardens the cover over years. Match the window to your operating climate before you order. A fleet in the north and a fleet in the desert need different answers from the same report.

Ozone and whip test how the hose ages

Two tests on a report rarely get read, and they are the ones that measure aging. The ozone test checks how long the cover resists cracking when exposed to ozone. It is the reason EPDM covers exist: EPDM holds up against ozone far longer than natural rubber. The whip test flexes the hose continuously to simulate road movement and checks the reinforcement and fittings for fatigue. A report with both tells you the supplier checked how the hose dies over years. A report without them leaves that question open.

How to check a report in one minute

Three checks catch most problems:

• The batch number on the report matches the batch on your goods. A report for another batch proves nothing about yours.
• The tests cover the claims. Burst alone does not verify ozone resistance or low-temperature behavior.
• The numbers carry their conditions. Expansion needs a test pressure, temperature needs a range, burst needs a minimum value.

That one-minute check decides whether the report goes in the file or goes back to the supplier with questions. Tests run to SAE J1401, the standard for hydraulic brake hose, and every Junze assembly ships with a batch report. See our standard brake hose assemblies and low expansion brake hose assemblies, or send us your spec and we will send the matching test data.