Replacing a Spring Brake Chamber

cage it off, mark your hoses, colored zip ties or a bit of telephone wire works good, disconnect your hoses, now disconnect your clevis, and you're ready to unbolt from the axle. Take that all to your bench take the clevis off the new brake can and leave the nut, cage it, take the clevis off your old brake can and set up next to your new one and determine where you need to cut the push rod. cut the push rod and run your lock/jam nut off the allthread because you left it on there so you don't have to go chasing threads, put your lock nut and clevis back on and repeat what I said at the beginning only backwards. get everything all back together and now adjust your brakes, all of them while you're under there.

Now I'm sure that someone else on here will come along and give a better detailed step by step instructions on this, but if what I just rambled on doesn't make sense, then I'd be a bit hesitant about replacing your own brake cans, as much as the DOT likes to go after a guy (driver, mechanic, company) for brake infractions, the liability may be less to just have it done. Let alone safety liability for one's one personal well-being...

Also, if the old can is rusted, I would VERY HIGHLY recommend AGAINST using any air, or impact tools to cage that brake can off, and position your body similar as to if you were doing show trimming on a calf that likes to kick, as little of your body in the 'line of fire' as possible. You should make sure however you get rid of that old brake can is going to disarm it before sending it to scrap.
Go to about the 13 minute mark of this video, it's a brake can off of a loader, and a cheesy old safety film, but it gives you a idea of what that spring will do.
http://www.youtube.com/watch?v=3_gEVILWVUM

 

Or, you could just change the bad diaphram. You could loosen the clamp holding the two parts of the chamber together, and let the can knock your head off when the spring lets go and shoots the can at you doing 100 mph.

ALWAYS change the whole assembly like mentioned in the first post if you don't know exactly what you're doing. The way I mentioned, which many DIY's have tried, can hurt or kill you.

 

It's a pretty easy thing to do. I chock the wheels, release the brakes, crank the slack adjuster all the way back, remove the pin from the clevice, and go from there. I only mark the service brake lines, personally, but marking them both certainly doesn't hurt. The only point when I cage is when I'm putting it back on.... if you do cage the can before you take it off, always, always, ALWAYS make sure you uncage it before you dispose of it.
Once it's off, I measure the piston length from the old can (leaving them uncaged makes this more convenient), cut the new one to length, THEN I cage the brake chamber.
once everything's installed, you want to adjust your brakes.... with a 30 can, I set them so there's two inches of brake stroke. Auto slacks are for fine tuning.. the coarse stuff, it's still manual.

 

You will need to get air brake Hose or have hoses made to reach those 2 chambers. We've had a sliding problem with trucks with only 1 axle with spring brakes. Adding 2 really helps.

 

If the service can is a type 30 u don't need to remove all of it just the back side and get what they call or I call a pig pack. This is just the diaphram, clamp and the emergency brake chamber or spring brake. You will also have to tee into the supply line for the existing spring brakes on the other axle assuming that there is spring brakes on one of the other axles. If this is on a tractor one axle at least should have spring brakes on it. So as I said just tee into the line going into the emergency side of that can and plumb that into the emergency side of the can you are putting on. The line that was on the service can u took off u can put back on the service side of the new can. The service can that u are takeing off should have no presure on it at all unless someone is stepping on the brake pedal in the cab. It will have just a little spring presure on it as u take the clamp off. What I do is just use a 3/8 impact gun and move to the side as I buzz one nut off the clamp and everything goes good. Good luck

 

Replace with Haldex Lifeseal brake chambers. A bit more money but they last forever and have a 7 year warranty.

 

you measure off of your old brake camber in most cases .
But putting on a whole new setup I would think you would mount the can and measure to the slack adjuster when you push the brakes against the drum would get you close.