HELP - Air brakes and weird warning sound

mapletwag · 01-09-2018, 12:07 PM

×Air brake help×

Basically when we turn the ignition to accessory mode an extremely high pitch beep starts coming from control panel and the primary break light comes on. This sound and light continues once the engine is on.. when we tried releasing the air brake, the knob just popped back out and wouldn't stay in the released position.
Max did some researched and basically thinks we screwed up the brakes... what happened was we bought the bus New Years eve and the guy showed us quick how to use the air break and let us drive it around the parking lot before we bought it. We drove it home all the way from Charlotte no problem about 90 miles. The first few days of December were pretty cold so we didn't start the bus because we have the Cat 3116 engine and heard they aren't the best in the cold. We tore out the seats, it's been maybe 7 days since the bus has been started. We did have the bus plugged in the whole time though to the heater block.
Max said what he read online was that in the cold weather there is some special maintenance which needs to be done to the air breaks?

I guess what I'm asking is how screwed are we? Has anyone had experience with this, or knows if, how, and how much$$ it will take to fix?

Please help, this sucks. We are soo bummed.

Brad_SwiftFur · 01-09-2018, 12:30 PM

Quote:

Originally Posted by mapletwag

×Air brake help×

Basically when we turn the ignition to accessory mode an extremely high pitch beep starts coming from control panel and the primary break light comes on. This sound and light continues once the engine is on.. when we tried releasing the air brake, the knob just popped back out and wouldn't stay in the released position.
Max did some researched and basically thinks we screwed up the brakes... what happened was we bought the bus New Years eve and the guy showed us quick how to use the air break and let us drive it around the parking lot before we bought it. We drove it home all the way from Charlotte no problem about 90 miles. The first few days of December were pretty cold so we didn't start the bus because we have the Cat 3116 engine and heard they aren't the best in the cold. We tore out the seats, it's been maybe 7 days since the bus has been started. We did have the bus plugged in the whole time though to the heater block.
Max said what he read online was that in the cold weather there is some special maintenance which needs to be done to the air breaks?

I guess what I'm asking is how screwed are we? Has anyone had experience with this, or knows if, how, and how much$$ it will take to fix?

Please help, this sucks. We are soo bummed.

How much air pressure is the gauges showing? There is supposed to be an alert under a certain threshold, usually around 60 PSI. Let the engine run to build pressure up and the alert should silence.

The parking brake is functioning exactly like it's supposed to; it is *NOT* supposed to stay in unless there's minimum pressure in the system. In fact, it is designed to pop out when the system drops to that level.

Air brakes do not require much "special" maintenance in cold weather. The air tanks should have drains on them to purge any moisture; these should be drained every day it's driven. Usually there's a pull cord attached to the valve specifically for this purpose, just give it a pull until "dry" air comes out (there may still be a little residual moisture in it). The other maintenance will typically be done once a year on an active bus and that is servicing the air dryer (there's a filter that should be cleaned/replaced).

Johnny Mullet · 01-09-2018, 06:45 PM

Brad nailed it. You need to run the engine to build air pressure and there is a gauge on the dash that tells you this pressure. When you get above 90 psi (give or take) the buzzer will go out and pressing the brake release will actually release the brakes.

Your air leaked out slowly after sitting.

Brad_SwiftFur · 01-09-2018, 06:55 PM

Quote:

Originally Posted by Johnny Mullet

Your air leaked out slowly after sitting.

Air leakage is *VERY* common on air-brake vehicles. If it only loses 1 PSI per minute while parked/turned off, that's fine (It's also under the federal guidelines which I believe allows a maximum of 2 PSI while parked; I'd have to look it up again to remember for sure).

I can only remember 1 truck I have ever driven that would hold 80 PSI for 2 months (farm use truck, we didn't use it daily, nor during the winter months).

mapletwag · 01-12-2018, 01:10 PM

Hey guys,
so i'm about to drain the air tank, i've watched a couple videos and I think I should be able to locate the wet tank - right?, easily. Only thing i'm not sure about is how long to pull the cord and drain the tank for? Do I just keep doing it until it stops on its own or is there a certain amount of time I need to hold it for?
Thanks!

Robin97396 · 01-12-2018, 03:05 PM

Drain the tank until there is no more moisture coming out.

Cover your face. A little eye protection wouldn't hurt.

mapletwag · 01-15-2018, 01:37 PM

Is this what I need to drain? I have two one at the front and one at the back.

Robin97396 · 01-15-2018, 02:35 PM

That should work. You may get sprayed.

Most buses have a more covenient way of draining the tank.

Robin97396 · 01-15-2018, 02:42 PM

Start your bus to build up air pressure. Shut it off and set your parking brakes. Crawl underneath and pull the ring that looks like a grenade pin straight down with just enough pressure to open the valve temporarily.

Hold the valve open until no fluid comes out. You're not looking for perfection, just get most of the juice out.

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