If you have a vehicle, such as a Land Rover Range Rover, long enough, you will eventually want a way to bypass certain components of the air suspension system. If you ever have a bad compressor, leaking valves, or bad air line connection at the valve block, this little adapter allows you to bypass the problem and continue riding on air. This adapter does not help work around problems with the air spring itself. The adapter is basically a Schrader valve to 1/4" compression adapter, but I built it using two separate adapters. Most air suspension vehicles use 1/4" OD air line or 6mm OD air line in the case of our Rovers. The 1/4" works out to 6.35mm, which is slightly larger than the Rover's 6mm air line. I could not get the flared insert completely into the 6mm air line by hand. After getting the brass insert started, I heated the brass insert with a lighter for 5-10 seconds and pushed against a hard surface to get it all the way in. This stretched and expanded the last 1/2" of the 6mm air line to the same size as 1/4" air line. The 1/4" compression fitting then had no problem biting down on the air line and forming an air-tight seal. The Schrader valve to 1/8" NPT adapter was about $3 online (can't recall the source) and the 1/8" NPT to 1/4" compression adapter was about $2 from the local hardware store, so the whole set can be built for around $20. This is far cheaper than other precision machined rescue valve blocks I have seen in the past.
Assembled Rescue Devices
Use teflon plumbing tape to seal the threads between adapters.
Getting 6mm Air Line To Fit 1/4" Compression
Get the brass insert started by hand. Then heat it with a lighter for 5-10 seconds, no more. Grip the cold portion of the air line and push it and the brass insert down on a hard surface. The heated brass insert will expand the 6mm air line to fit and the brass insert can be inserted fully.
I attached my test air line and EASRD to an air tank with new o-rings. I pumped it up to 50psi and waited 48 hours. It held great and I was unable to detect any leak from pressure drop or soapy water.