What do you use the trolley valve for?

Well 2 things wrong with that plan.

The blue and red gladhands are made so you can't do that for that reason..

Wouldn't apply air properly because the spring brake would still be applied...

And really who wants to hook up jump up and press the red (to check service) walk around then pull the red hook them up properly jump up and press the red and walk around again (to check emergency)

 

You can buy a universal glad hand the will hook to either.

I know this does not help the conversation. But its possible.

 

I carry a universal

 

Not really, 2 different sides of a brake chamber service side parking side. Except steer axle.
I release my parking brake on trl then apply my trolley valve. I can then hear any air leaks on trailer from both circuits. Also check brake lights as well.

 

I thought they were all universal. I've never actually encountered ones specifically for service and supply.

 

Have to dumb it down to make it as easy as possible and as cheap as possible.
I mean heaven forbid they actually trained the newbies

 

Recent year Red and blue do not easily connect. Or stay connect. They are formed different.

 

Usually just gold anodized.

 

It's foreign language to them

 

I call it the magic handle.