Tag Axle MCI-9

[Kwajdiver]

Guys,

How do a get my tag axle up?  Does it come up?   

Bill
1983 MCI-9

[Dallas]

A Jack and some chains.

Or some Cialis, but if it stays up more than 4 hours, you have to take it to the Emergency Room! 

[Frank @ TX]

Hi,
The tags on  normal MC-9 do not raise.
They press down ur if the "tag unloaded" swith is on the tags will just have their own weight on the ground ( about 500lbs ).
Some folks installed a different kind of air bag system that can raise the wheels , but that's not how the 9's came from the factory.

You could use the chains to hold a tag off the ground but you would first have to jack it up to fit the chain.
Frank

[Kwajdiver]

When I toggle the Tag Axle switch, I get an alarm sounding.



Bill

[JackConrad]

The alarm is telling you there is no pressure in the tag axle air bags. If you drive it like this, the handing is not as good and if you apply the brakes, you will slide the tag axle tires.  As was mentioned, if you need to raise a tag, flip the switch to release the air pressure in the tag air bags, jack up the axle and use the short piece of chain that should be on the tray above the bus batteries. There is a hook on top of the tag axle and a hook on the frame above the tag axle.  If you chain up one axle, flip the tag axle switch when done to apply air pressure to the other tag axle airbag.  Jack

[Hi yo silver]

Jack,
Are you saying you can chain up the tag on one side, but not on the other side?  That never occurred to me.  Duh!
Dennis

[Hartley]

Tags on a 9 are independant of each other, The only common elements are air bag and brake lines.

Beware of the "Squirrel" behavior which happens with the tags unloaded.. The front end will be everywhere when you least expect it. The crown on the road will be obvious.

Dave....

[buswarrior]

Hello

Hold the fort!

A stock MC9 tag axle (and MC7,8 and early 102) has three possible conditions:

1) normal - air pressure of approx 35 lbs, as fed by a regulator on the bulkhead under the washroom, midships.

2) dash switch activated - air pressure of approx 15 lbs, as fed by another regulator, mounted with the first one, and valving switched by a solenoid. The dash switch activates the alarm, regardless of change in tag bag pressure. (Take wire off solenois, alarm still sounds)

3) dump manual tag valve inside curb angine door axcess - now there is no air in the tag axle suspension, for the side that you opened the valve.

To chain up a tag axle, you have to dump the air by way of the manual valve. Back onto a curb, or a run up block and the chain with the big loops will fit over the two hooks. Drive off and pressurize the tag again to keep it all tight, if you are able.

Jack is quite right, you will flat spot the tag tires if you brake with the dash switch activated. You will not like the rythmic thumping....

These regulators are a worthy item to inspect and check that the proper air pressure is being applied, and that the electic bits are actually doing the partial unload job they are designed to do. A suitable fitting inserted at whichever joint will easily come apart and your tire pressure gauge will do the trick!

As the design of our coaches was intended to protect the owner's investment from less than caring employees, we might decide to change the function of the dash switch to really lighten the tag load by adjusting the appropriate regulator to as light a setting as it will adjust.

I still wish a locking differential was easily installed in an MCI, much more effective!

happy coaching!
buswarrior