BCM Community

Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: AJ on July 07, 2009, 09:24:28 AM

Title: Air Source
Post by: AJ on July 07, 2009, 09:24:28 AM
On a MC8, if you were to air-up your tire, say 110 PSI max, where would you tap in?
Title: Re: Air Source
Post by: NJT 5573 on July 07, 2009, 10:38:42 AM
AJ,

I don't know MCI's, but in general you should be able to pick any of the air tanks. Preferably not the first one behind the compressor because it usually catches some moisture. Once you get a plug out of your tank of choice, put a valve stem in it and check for the available pressure. If its high enough, plumb the air line for your hose. My largest tank is between the steer tires and its easy to plumb air from there to the front cargo bay.
Title: Re: Air Source
Post by: jackhartjr on July 07, 2009, 01:23:59 PM
AJ...just remember the first 90 or so PSI goes in in about 5 or so minutes, getting the other 10 to 20PSI can take about that much longer.
I have seen folks plumb in an glad hand like trucks use with a shut off...then have what I call a 50 foot cheater hose with the glad hand on one end a double ended air chuck on the other.
Jack
Title: Re: Air Source
Post by: buswarrior on July 07, 2009, 03:25:47 PM
A convenient source of DRY air in those MCI would be the aux tank under the driver. Plumb in the connector and valving of your choice.

For airing tires, stay away from the discharge muffler or the wet tank.

As noted, having a universal gladhand available to you in your mix of tricks lets you get help from/give help to a trucker.

happy coaching!
buswarrior
Title: Re: Air Source
Post by: ol713 on July 07, 2009, 08:37:59 PM
Hi;
    I also used the aux tank under the driver.  It is in the service bay
    under the driver.  I installed a "T" and a quick disconnect for your
    air hose.
                                   Merle.
Title: Re: Air Source
Post by: RJ on July 08, 2009, 01:14:38 AM
AJ -

Altho this is on a GMC, it will give you a visual of what tapping into the aux tank under the driver looks like:

Title: Re: Air Source
Post by: Tony LEE on July 08, 2009, 03:36:32 AM
The only caution in "stealing" a lot of dried air from the end of the system might be that it results in wet air getting through the system because the flow is higher than what the dryer system can handle. Not a problem for the tyres, but could cause problems for the brake and other systems.
Title: Re: Air Source
Post by: buswarrior on July 08, 2009, 06:48:17 AM
Tony brings up a good point, moderate your air use so that the air system may reach cut out and the air drier is allowed to purge once in a while.

I expect you'd only have a problem if you started running an air tool constantly, consuming all the air the compressor is making. Topping off tires won't consume enough air to make it any different than some "normal" coach functioning.

FWIW, a regular air drier reaches saturation somewhere after 10 cfm passes through, so airing up the bus from empty has done that. Transit buses and garbage trucks in high humidity cities pass moisture to the wet tanks, regular air driers are quite overwhelmed. They still remove a lot of moisture, it's just that they can't keep the wet tank as dry as some of us have grown accustomed to.

Also, an air drier in a leaky teaky will pass more moisture for the same reasons, too little purge time, lots of pumping time.

happy coaching!
buswarrior