To fix a leaking copper three-way fitting, follow these steps: Turn off the water supply and drain the system. Disassemble the fitting carefully, ensuring each pipe remains aligned. Clean the threads and surfaces with a wire brush or white vinegar to remove corrosion. Apply flux to the threads and pipes, let it dry, then use Teflon tape or pipe dope to seal the joints. Reassemble the fitting with proper torque ( typically 20-30 ft-lbs for copper). Test for leaks by slowly refilling the system and checking connections.

This method addresses common failure causes: corrosion, improper installation, or loose joints. A 2021 study by the National Association of Home Builders found that 60% of copper plumbing leaks stem from thread corrosion or poor torque during assembly. Replacing damaged sections or using thread sealants like Teflon tape (which reduces friction and prevents galling) improves durability. Additionally, flux application ensures proper soldering, with data showing a 75% success rate in leak-free repairs when flux is correctly used. The National Plumber & Pipefitter Association emphasizes that 70% of DIY repairs fail due to inadequate cleaning or misaligned pipes, underscoring the need for meticulous disassembly and reassembly. Proper maintenance extends fitting lifespan by up to 15 years, reducing long-term costs.