No Brakes

[IndyCutter]

I Got up today and my Air Brakes won't come up to Pressure. they worked fine yesterday. There is no pressure showing on the gauges. I realized the Air Dryer Filter is way over due for a change. Could this be the problem? Any ideas would be helpful.

I've got a 99 Cutter on Freightliner Chassis with a Cat 3126

[markdoane]

Does it get below freezing where you are? It could be ice in the lines.

Do you drain moisture from the tanks?

[IndyCutter]

I drained the lines...no water. It was in the 50's here today I am from Indianapolis and it has been freezing there. any chance the lines were damaged before I dorve it? I drove 600 miles with no problems.

[Partsman]

Does your Air dryer blow off very frequently? Have you installed a governor recently? Have you checked for leaks? When you say it 'won't come up to pressure' does that mean you can build air but not fast? or, it gets to a certain pressure and stops? How many miles or hours on engine? When you step on the brakes do you hear any air excaping from anywhere?
Where are you located now?

I work in the Heavy truck industry, will at least try to steer you in the right direction.

Chris

[overlander63]

Is your compressor belt-driven? This sounds gross, but it happened in our shop last Saturday. A rat crawled into the warm engine compartment, and fell asleep across the A/C belt. When the driver cranked the unit up in the morning, it caused the belt to jump off the pulleys, with the added joy of cutting the rat in half. Without going further into messy details, I removed the rat, and installed a new belt.
If that is not the case, you may have a line off at the compressor, a drain that didn't close all the way, or a couple more minor issues, before you get into the stuff you wouldn't want to tackle on your own. Good luck with it.

[IndyCutter]

It doesn't build air at all. At Idle the air gauges stay on "0" I looked underneath for a belt problems but didn't see anything. I had drained the tanks of aie when I noticed the problem just too see if there was water in the lines. It hasn't had air since. I've scheduled a Cat mechanic to come by this morning to take a look. Thanks for the replies. I'll post the problem/solution when we figure it out.

[GlenCoombe]

Not sure about state of the art these days. But this happened to me a long time ago on a highway tractor I owned.
I spent a few cold hours replacing what I thought was a bad regulator in the air line only to find out that the break cams needed lubrication. A few shots from the grease gun allowed the system to close and build air.
Take a look at your system for grease zerts.
Best of luck.