440-516 Generic 1/4 x 5/16 Inch Water Line Fitting Universal Water Filter and Fridge Water Line Part

Part 440-516 is a generic 1/4 inch by 5/16 inch water line fitting from the Crystal Clear range of hose, fittings and filters. These two sizes turn up on fridge water supply lines, inline filters and under-sink filter systems, where one size of tubing often has to meet another. It's an aftermarket universal part, not tied to any one appliance brand, so check the photo against your setup.

Joining 1/4 inch and 5/16 inch water lines

Small water lines are sized by their outside diameter, and 1/4 inch and 5/16 inch are both common on fridges and filter kits. Mixing the two is where a fitting like this comes in. A worn, cracked or wrong size fitting usually shows up as a slow drip, a damp cupboard floor or a tube that pulls out of its connection. When tracing a leak, dry everything off, run the water and watch each joint, because water can travel along a tube and drip well away from the real source.

Part details

• Generic part 440-516
• Size 1/4 inch x 5/16 inch
• Universal fitting for small bore water lines
• Part of the Crystal Clear water hose and fittings range

Tips for leak-free water line joints

Turn off the water at the isolation tap and relieve the pressure before undoing any line. Cut tubing square with a sharp tube cutter or blade, never with side cutters that crush it. With push-fit connections, push the tube fully home and give it a gentle tug to confirm it's held. Turn the water on and check for drips over the next few hours.

Questions about this part

How do I tell if my tube is 1/4 or 5/16 inch?

Measure the outside diameter of the tube. A 1/4 inch tube is about 6.35mm across and a 5/16 inch tube is about 7.9mm. Many tubes also have the size printed along their length.