So I have made some -AN line’s for my build, and I wanted to test them for leaks before the car was started. Only thing was, -AN test plug kits are around 50-60 bucks. If you have 2-3 different sized lines on the car it can add up quick - and we all know if you have gone for -AN lines, then you are already broke!

I was pumping up the mountain bike tyres one arvo, and realised that the tubeless valve stems on the bike would be just the trick! You can them from any bike shop.
Tubeless valve stem = $4
2x -AN plugs =$8
Custom DIY -AN line tester $12👍