| Author |
Message |
Mike Heron (Mike_in_ga)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 3:46 pm: | |
When at a campsite I occasionally need to operate an air tool, and I thought I could simply tap into the bus, when aired up, for this. I can only seem to get 35-40# of air off the accessory tank in the front left compartment of my MC96a3. There is also a chuck at the right rear near the dump valves for the trailing axle, but I get nothing there. Do I have to resort to an electric compressor to operate my air jack or to bring my tires uo to spec?
Mike in GA |
John MC9
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 7:03 pm: | |
Some observations I've made on my MC9?
1. The valve for the r/rear chuck has to be on. I use vice grips.
2. If there's no air in the bags, it doesn't come out that chuck either. |
Stan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 8:10 pm: | |
On earlier models of MCI the chuck in the tool compartment under the driver's seat is for tow truck use to connect a hose to release the bus brakes. It should have a check valve before the chuck to prevent any air out. If you are getting some air then the check valve is leaking. |
Geoff (Geoff)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 8:16 pm: | |
The accessory tank usually has a regulator on it to limit the air pressure the tank will build up- it will not build up as high of pressure as the wet tank or secondary tank (if you have three tanks). Are you saying that the air pressure gauge is reading 120 psi and you only have 35-40 psi from the accessory tank? If so you need to locate the wet tank (first air tank from the air compressor) and tap into it.
--Geoff
'82 RTS AZ |
Tom Caffrey (Pvcces)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 10:42 pm: | |
Geoff, that's funny. Our pressure gauge reads the pressure of the auxiliary tank. The only regulator that I know about is the one that prevents air from entering the auxiliary until the main tank reaches 65 psi.
Around here, that's called a minimum pressure valve. I think it's purpose is to make sure that a minimum pressure of 65 psi can be maintained in the main tank if the auxiliary system springs a leak.
In the event that air is pumped into the auxiliary tank from a compressor, the main tank will get enough air to keep it at virtually the same pressure. This air comes through a check valve between the tanks.
I don't know what other kinds of buses might use.
Tom Caffrey PD4106-2576
Suncatcher
Ketchikan, Alaska |
Geoff (Geoff)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 26, 2006 - 7:32 am: | |
You are right, Tom. I got it confused as the accessory tank has a tendency to lose air faster than the main tanks, so when parked (engine not running) the accessory tank can bleed down while the air pressure gauge is still reading over 100 psi. There is a check valve in the air system that allows the accessory tank to lose all it's air and not draw out of the main tanks, so while the air pressure gauge is reading high with the engine shut off, the accessory tank is actually low on air pressure.
This would explain Mike's problem.
--Geoff
'82 RTS AZ |
Doug Dickinson (Dougd470)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 26, 2006 - 9:27 am: | |
I did much the same thing in my MC9 on the forward aux tank, Mike. Remove the check valve and put a chuck AND VALVE in the lower fitting in the tank (there should be 1 or 2 vacant and plugged holes. This tank will give you system pressure, but only when the buss is fully aired up. It is at the "end of the line" so to speak so it gets the last air in the system. This is usually fine for most tools.
The air valve and chuck in the rear compartment is for airing the coach up and is connected to the output of the air compressor. The only time it presents air is when the compressor is actively putting air in the system (on demand. When the coach is fuly aired, there is no pressure on that line until the demand requires output of the compressor.
The MC9 manual has a good diagram, but I suggest an electronic version that you can blow up and actually read. I made an E size drawing to easily read all of mine. Lots of little things you will want to know about.
Doug
St Louis MC9 |