How to disable a brake chamber

Yup caging the brake only puts the parking brake out of commission.

His problem is in the service side .
His problem will still exist caged or not.

He needs new s-cam bushings or something else is wrong maybe the small spring in the sevice side of chamber is broken not making the s-cam return

 

That's right, I hadn't thought about the service brake. He'd have to plug off that line too. Wonder how he made out.

 

Pull the air line off at the brake can, fold it back over itself, and put a pair of vice grips on it. Back the brake off and go somewhere to fix it.

 

Some auto slacks have a locking mechanism on them to prevent them from backing out. Some have a ratchet mechanism and you just turn the adjuster bolt to slack it off. Others have a collar around the adjuster that needs to be pressed in firmly with the wrench so you can turn the adjuster bolt. Rockwell's have a little spring loaded button about the size of a dime on the side of them that needs to be popped up to disengage the adjuster bolt. I assume you know that the brakes need to be released in order to slack the adjusters off.

If you need to limp it to a shop, cage the park chamber and pinch off the line to the service side of the chamber with vise grips. Then you can slack off the brakes at the adjuster and get it to a shop.

 

Put wheel chocks under wheel, release brake. Lose two nuts holding air chamber to the collar. Remove pins, remove air chamber carefully. Check the slack adjuster is it good if you have automatic adjuster it's common this small push rod got out of gear and adjuster is locked. Make sure you put air chamber in same position on the collar it was before. There is two holes looks like one long but you cant slide chamber up or down.

 

Caging the brake only eliminates the parking brake. Doing so pulls pressure off the spring that sets your park brake. Your service brake ( when you hit the brake pedal) will still function as normal. To eliminate that pinch the line or cap the line.

 

It's in a bind or seized,you may have to put some heat on it.
When you back the brake off how much does the adjuster move?

 

Not to muddy the water but.......

Sometimes with an older trailer (not sure how old yours is) the junction valve gets full of crap/ corrosion . This ends up starving a wheel or two of air. And can produce the symptoms you are describing......