How do D.O.T transmission fittings ensure leak-proof connections under varying temperatures and pressures?

D.O.T transmission fittings are designed with specific features to ensure leak-proof connections under varying temperatures and pressures in automotive brake systems. Here are some ways they achieve this:

1. Compression Sealing: D.O.T transmission fittings use a compression-style design. They employ a combination of a threaded connection and a compression ferrule or sleeve. When tightened, the compression sleeve compresses against the tubing or hose, creating a tight seal and preventing leakage.

2. O-Ring Seals: Many D.O.T transmission fittings come with integrated O-rings. O-rings are made of elastomeric materials and are placed within the fitting to create a sealing barrier. These O-rings help prevent leaks even under high temperatures and pressures.

3. Tapered Threads: D.O.T transmission fittings usually have tapered threads rather than straight threads. The taper ensures a tight seal between the fitting and the corresponding connection point. As the fitting is threaded into the receiver, the taper compresses against the receiving threads, resulting in a secure and leak-proof connection.

4. Use of Flare Fittings: D.O.T transmission fittings often utilize flare-type connections. Flaring the end of a tubing or hose allows for increased surface area contact between the fitting and the tubing, enhancing the sealing capability. This method ensures reliable and leak-proof connections, especially in high-pressure brake systems.

5. Testing and Certification: D.O.T transmission fittings undergo rigorous testing and must meet specific performance standards set by the Department of Transportation. These standards ensure that the fittings can withstand the demanding conditions of automotive brake systems, including varying temperatures and pressures, without leaking.

Overall, the design, materials, and testing of D.O.T transmission fittings are tailored to provide reliable leak-proof connections under the specific requirements and demands of automotive brake systems.