Air brake troubles

[winniman]

I dont think most people realize there is a spring inside the chamber capable of taking your head off. Giving someone half the information to do a dangerous job can be potentially hazardous. Not saying you are not capable, but lots of people are trying to rv on a budget. Reading that changing the maxi pot is easy could lead someone to tackle a job they really shouldnt be touching. Its not like changing your oil. If they dont adjust the push rod correctly, they will have non functioning brakes.

[twinboat]

Serviceable spring brake chambers were discontinued in 1989, and clamped permanently. Most of the pre 1989 ones should have been replaced by now.

The only way there can be any real danger of the modern MHs brake chamber knocking someone's head off, is if that person repairing it, goes at it with a hacksaw or cutting torch.

As far as a bad adjustment, the " auto slack adjusters " should get the adjustment back to specs in a few brake applications.

Can it be screwed up, of course it can. I've seen a few in my career, but no one was injured.

Unless your replacing all 4 chambers, badly, you'll have some brakes and will, hopefully, seek help from someone who can assist in fixing it.

[alounsbe]

One interesting wrinkle when I changed the air chamber was that I was unable to get the caging bolt to engage and had to remove it under spring load, when I got it removed I looked down the engagement hole with a flashlight and saw that when the diaphragm in the spring chamber ruptured what looked like a cap head screw was sticking through the ruptured diaphragm into the caging bolt slot preventing it from going in deep enough to engage. If you ever have to remove one under load don't be behind it when you take those nuts off.

[twinboat]

Originally Posted by alounsbe

One interesting wrinkle when I changed the air chamber was that I was unable to get the caging bolt to engage and had to remove it under spring load, when I got it removed I looked down the engagement hole with a flashlight and saw that when the diaphragm in the spring chamber ruptured what looked like a cap head screw was sticking through the ruptured diaphragm into the caging bolt slot preventing it from going in deep enough to engage. If you ever have to remove one under load don't be behind it when you take those nuts off.

That is why you back off the slack adjuster first, until the rod is sticking out of the chamber.

Doing that lets the spring expand inside the chamber, eliminating any external force on the mounting studs.

[idoxlr8]

Boy this conversation brings back memories. Used to be the manufacturing engineer for Midland Brake back in the 90s during the time the spring side went from clamps to the roll form style. We made zillions of 30/30 spring brakes years ago. Those springs in them are no joke, very powerful and certainly demand your respect.