What purpose do these things serve.

chazwood · March 06, 2009, 05:57:39 AM

Attached to the inside back wheel well, on either side, there lives a little dirty pressure release valve that looks to be connected to the tag axle air.
What is this little thing, the size of a tube of lipstick, for?

Tenor · March 06, 2009, 06:24:36 AM

Those are manual air dump valves to let air out of the tags. Why? To get more grip from the drive wheels when needed. I had to ask the same question.

Glenn

jackhartjr · March 06, 2009, 07:49:48 AM

when needed...is usually in snow and ice.
Jack
The Scenicruisers have a dump lever in the dash area to do this from the seat.

PP · March 06, 2009, 08:29:14 AM

Hey Chazwood, good to hear from you.

On the Prevost, we just lift our tags like a little girl raises her skirts to cross a puddle.

Take care,
Your extended Family

buswarrior · March 06, 2009, 07:29:35 PM

Give us some pictures.

The manual dump valves for an MCI are inside the curb side, side engine access door, tight inside the door hinge, in the space between the hinge and the back of the tag wheel well.

Nothing stock on the road side wheel well, at least, that i know of.

Enlighten us!!!

happy coaching!
buswarrior

JackConrad · March 07, 2009, 04:25:54 AM

I think that is an overpresure relief valve. If the pressure in the tag air bag gets to high, it releases the pressure. I found this on our MC-8 when I was trying to free a froze tag axle several years ago. I disconnected the air line to that tag axle air bag and connected it to my shop air through a regulator. I figgered I would increase the pressure until the tag axle started to move. At about 85 PSI, I found that the pressure relief valve was working. Scared the bejeebers out of me. Jack

busnut104 · March 07, 2009, 05:29:21 AM

I reinstalled my valve in the driver area, I now can dump or raise or lower pressure from the driver seat. I used the same valve that I have in my tri-axel dump truck.

poppi · March 07, 2009, 07:43:00 AM

If hard pressed one can use the tag for a spare tire. The tag can be chained up. I have a chain made up
just for such an emergancy. All you do is dump the air back onto a block, chain it up and finish removing the tire.
I also carry the spare.

With no pressure on the tags some have had different result on the handling.

FWIW

Skip

Tony LEE · March 07, 2009, 09:25:57 AM

You said you had one on each side on the inside of the wheel arch. MCIs have a Tag Axle Low Pressure Switch in that location - brings up a warning light on the dash