Junk I'm a betting man. I say the unloader is that device sitting on top of the cylinder head and the line going up to it is what you are looking for. They do make 1/4 inch compression couplings if I'm wrong...... /forums/images/graemlins/grin.gif
What PSI are you guys running? I was getting ready to place an order for a new compressor for Dad and was going to order one of the auto drains for me and my lowly Craftsman, but I typcially run it at 145 PSI with an oulet PSI of 90 - 120 depending on what I'm running. Harbor Freight's website says that it is only good for 100 PSI. I can't believe you guys are only running 100 PSI though.
PS Don't get me started on how bad the Harbor Freight stores - or at least their help is. Makes Lowes look like 5 star restaurant. /forums/images/graemlins/grin.gif
Kubota B2710, IH TD6-62 dozer with Drott 4n1 bucket loader
My compressor is 150 psi shutoff and I run at 90 psi after the regulator. My HF auto drain works with no problem but I did change the plastic tube to 1/4" copper tubing using new correct fittings.
I was also unsuccessful finding one that was rated for over 100psi and I run 150psi in my tank. So I chickened out and went with the ball valve vented to the outside. Works fine.
More than a few of us are using the auto-valves at pressures higher than they were rated for. I haven't had a minutes problem with mine since I installed it.
I guess this also means that I'll be visited by the TBN security safety enforcement team. Man I hope those guys ain't too big. /forums/images/graemlins/tongue.gif