Installing a shut-off valve to the air brakes for trailer???

What, that's what I did when I had a trailer start locking up on me for no reason. Had to get down the road to the shop they wanted me to take it to after dropping the load.

Just don't block it entirely with the quarter. Offset it to make the hole smaller so it takes longer to build pressure. It will act like a poor man's regulator without cutting off the air.

It sounds like it might just be sending to much pressure through the service lines.

 

How about something to regulate the air pressure instead of cutting it out totally? I have no idea if anyone makes a regulator big enough and fast acting enough, but it seems like you could limit it to, say, 15psi and still have some brakes, but not enough to lock it up. I have absolutely no experience with this, just an idea. I pull a fairly light (9500#) flatbed, and pull a fair number of light loads myself, and I've considered doing something similar. I don't know if QC would go for this or not, but you might be able to talk them into it to save on tires, but installing a valve to dump the air from the front airbags and cut their air supply, and then strapping or chaining up the front axle might do something for you, getting all the weight on four tires instead of eight. I'm planning on doing this to my trailer over my time off the next couple of weeks in lieu of a real lift axle.

Some of these scalehouses have thermal cameras to check brake drum temperatures as trucks come off the interstate now. When the camera senses a cold drum, it alerts the scale operator to (potentially) pull the truck around for an inspection. Obviously, you'd open your valve back up and pass the inspection, but this could lead to you getting inspected more. I don't know if any of the scales you go through have them or not though, several of the ones around here do. All that to say, it seems like having an in-cab switch like what Jfaulk's talking about would be the way to go, just shut the air off when it gets nasty.

It totally amazes me that somebody can come on here and ask for advice on making his truck/trailer easier to control and have a shorter stopping distance, and people tell him to leave it alone in the name of "safety." Not sure if you ABS guys realize this, so I'll cut you some slack, but these are trailers that SHC doesn't own, it'd be insane for him to retrofit ABS on them. And besides, if anybody makes an ABS system that actually works like it supposed to, especially on an empty/nearly empty trailer, I've yet to see it.

 

Lift axles on trailers up this way are legal when empty.

You can't just dump the air out of the bags and let them ride along as you will pound the hell out of the cones inside the air bags.

 

Which is why I said to chain the thing up.

 

Something ain't right. They shouldn't be locking on you if the ABS is working properly.

Maybe the shop guy is confused on how to adjust them properly. If they are manual adjusters, you can always back them off a 1/4-1/2 turn rather than trying to regulate the air.

 

This is WABCO brake presure regulator for air suspention. More pressure in air bags - more pressure in brake chambers.



This is regulator for leafsprings suspention.

tommorow I can post Wabco #. They are not expencive. easy to install.

With metric threads for EU marker and cone threads for US market.

 

Unlike you I do not feel the need to play father. If he asked what was the best way to set his truck on fire and I knew I would tell him. I don't care why he's doing it. I know what he's dealing with, I had a flat that had worthless brakes and I threw the ABS valve in the dumpster and installed a non-abs valve in its place. Now if it would make you feel better feel free to preach to me about the "all trailers mfg after 19xx must have ABS" law feel free. ABS is great for keeping the trailer straight......straight into the vehicle in front of you.

You guys should try answering a question without the sermon.

 

nice find pablo.

that looks nice..

 

You can always install a bobtail valve on the trailer to reduce the pressure.