How much air does it take to unlock trailer brakes?

60 psi will fully release the spring brakes, and like @Skateboard said, you have to get somewhere above that before air goes to the bags.

Unless there's a major issue, a 10 gallon tank @120psi will more than do the trick

 

Ya, I just went through this watching my mechanic replace an air tank, relay valve, brakes, drums and a brake can. I didn't do a thing. He found an electric powered wheel chair at the dump and fixed it. When I'm there I ride around in it. It's freaking awesome!

 

This is probably the best idea so far.

 

Took me a while to find this thread. At my companies yard currently and remembered you had made this thread, this is what they use to move our trailers around with a John Deere 644k wheel loader. Don't know if you ever made anything but figured would share pictures anyway

 

A ten gallon tank is not gonna cut it.

You are looking at 70 pounds PSI going into 4 brake chambers that have springs inside of them capable of locking the wheels. You want a tank as big or bigger than the one on the trailer at the tandems. 120 is ideal.

Winter time, you have the additional problem of icing. Once in a while a ball peen hammer making ding ding music on the wheel drums rather than the thuk thuk of frozen pads tell you that wheel released. Chock your tractor first.

Maxi bolts is the proper term, these things are about several inches long by very thick. It's going to be about a one inch nut driving it in. You would have to do it by hand because a impact is too short. Need 4 of them for the two axles of your trailer.

It's probably way better to whistle up a jockey down the street, he can scoot and grab that trailer. Or any bobtail can do it. You can probably buy a junker bobtail out of a rust yard for a few thousand or less. It might be a air start but it will work.

 

That's a clever fabrication; I dig it!!

 

Au contraire.

The Lisle one is the one to get. No way in #### would I pay Snap-On's prices for that thing.

 

if the trailer has air ride just unhook the air line going to the leveling valve and cap it

 

To the guys talking about caging the brakes, I had the feeling the op is not interested in caging every time he moves a trailer around. The tractor idea for a couple gees sounds like the easiest way to move around flatbeds with air ride.

 

I got the Snap On one, Can't remember what it cost me but I don't remember it being like some of the times where I need to be sitting down. I don't mind getting odds and ends like that at full price, my dealer has seriously hooked me up with some barely used tools that sure make it come out in the end.

That attachment for your loader looks like the absolute cat's meow.