Tag lift for MCI 8

[skipn]

   Has anyone built a driver control tag lift for a MCI 8 or like coach? Is it worth the effort and/or price?

   More than once I have gotten stuck where I had to back off tag pressure to move.

   Thanks
  skip

[Tom Y]

Skip, I have heard some talk before on this. I do not have a tag on my bus, but was wondering if it is possible to put an air bag on it that works both ways like the tri axle dumps around here.  Just a thought.  Tom Y

[rayshound]

Skip;
      If you have the mci maint manual it shows the p&ID or air plumbing picture. It shows what you have then it shows the optional switch on the dash and the plumbing for it. Basically if you don't have the switch it has one air regulator and skinner valve. If you have the optional switch there is two regulators and two skinner valves set at two different pressures. I had purchased both regulators & skinner valves but I am not at that point in my conversion to do this mod as yet.  Ray

[DuaneMC7]

Hi Ray,

Dose that install "lift" the tag or just release the bag pressure. I have a 7 and I would like to be able to lift the tag.

Thanks, Duane

[JackConrad]

I added a couple solenoids to the air lines to the tag axle air bags that allow me to dump the air in the tags from the drivers seat. Unlike to OEM sytem, my system dumps all the air pressure in the tags. This has "saved" me a couple times when the rain Gods were not friendly while we camped for the weekend. This system does not lift the tag axles.  Jack

[NJT 5573]

Skip, If you can turn off and dump the air thats a start. Put a jack under it and see how far off the ground it will come before it hits the internal air bag stops. Is it enough? If it is you can figure the geometry to fit another air bag to work opposite the ride bags. There are several designs we use to do this on heavy haul trucks and trailers. Take your pick. I use an adjustable valve on my truck axels to vary the weight on each axle from 0 lbs of air to 120 lbs of air to the bags. I've got a feeling if you want to go very high off the ground you better see if MCI ever offered an option and see how they did it. Prevost makes one to.

[prevost82]

Hi Skip ... if you can look at a Prevost.... the tag axle lifts. Prevost uses a air value on the dash (like a alxe interlock switch) it dumps the air on the tag bags and lifts the axle, Prevost uses a small brake pot to Lift with a bellcrank arm and a chain to the axle. ... very simple. Having the ability to lift the tag axles helps alot for traction in snow, mud and sand (desert)
Ron

[tekebird]

the MC8 was not offered with a lifting tag.......only a tag air dump...

not sure of reasoning of lifting or dumping the tag when it has rained alot while camping...this will only cause you to sink faster.

Dumping the tag air is udes to add weight to the drives ie in a snow storm for traction

or Lifting to do the same as above, or reduce turning radius

[DrivingMissLazy]

the MC8 was not offered with a lifting tag.......only a tag air dump...

not sure of reasoning of lifting or dumping the tag when it has rained alot while camping...this will only cause you to sink faster.

Dumping the tag air is udes to add weight to the drives ie in a snow storm for traction

or Lifting to do the same as above, or reduce turning radius

I almost got stuck one time. It had rained and I was parked on a grassy campground site that was facing slightly downhill. When I tried backing out of the space the drive wheels just wanted to spin. If I could have taken the pressure off the bogie axle I am sure I would not have had a problem. I did finally get out without a tow, but I smoked a lot of rubber doing it.
Richard

[buswarrior]

Hello.

Long, long ago, I weighed the tag axles on an MC8, air on, dash switch activated and valves dumped in the rear.

Something like 3700 lbs working, 1500 lbs on the switch and 800 dumped? Or something close to that relativity...

Did a bunch of weighing with one that kept sliding the tags under braking, (not enough air pressure to squeeze them on the ground) weighed my own, replaced those pressure regulators, weighed it again, probably have some of the numbers mixed up between pounds and kilograms.... but you get the idea....

The switch needed to leave some air in the bags for the "hired driver" that wouldn't use it properly. With no air in them, they bounce along.

I've driven old MCI and new MCI and Prevost with lifting tags.  Here in the snow, seems to me that the tread pattern on the drive tires is the more important determiner of how much trouble you will have getting the coach to move off, not which method you have to lighten the helper axle.

High miler all position tires are going to give you grief, no matter what system you use, something with some blocky tread is much nicer, and will often work fine without bothering with the tag unload/lift.

Something else to consider, the tags offer quite a bit of assistance in directional stability: they resist the coach moving sideways. Once the drives start spinning , they do not offer any sideways stability and the rear of the coach will seek the downhill direction, usually towards the ditch/curb.

Like everything else, there's no free lunch! Get an advantage at the expence of some other disadvantage!

happy coaching!
buswarrior

[NJT5047]

Pete RTS has just  what you need.  He builds small electric/air leveling panels that would work for your "tag dump"....wouldn't raise the tags, but according to an MC 9 owners manual, would add proximal to 2K to your drive axles in slippery conditions.  Pete's device would allow you to unload and reinflate the tags from the drivers seat...without engineering your own system.    If your coach is similar to an MC 9, the tags can be manually dumped at the RH rear service door.    There's really no reason to lift the tags...unless you have plans to use it as a "spare" wheel assembly.   MCI does not reccommend operation of the bus other than at low speeds with a tag chained up.  You can lift them and keep them up in an emergency by chaining them.  You may be aware of such...but if not....there are chain slots in the tag axles for that purpose.   
Sonny G installed lifting tags on his Eagle...pix in this months BCM.  He would appear to be the resident knowledge base for such modifications.  He also installed "true dual" tags.       
BTW, anytime you manually dump the tags, when returning to an "aired" condition, verify that the tags are aired up.  My valves are not correctly oriented to the door chart, and must be moved to a different position to inflate.  The tags can be felt for inflation by reaching over the tag wheel.    FWIW, a totally deflated tag will articulate enough to get about 4" off the ground...this number varies by the ride hight of the drive axle airbags.   The tags can bounce on the ground during turns and driving through dips in the road.   Could damage something...tires etc.   I would doubt that installing lifting airbags would add much to the raised height of the tags.   Sure want to know before modifying the tag airbags. 
JR





   

[captain ron]

My MC8 has tag dump from drivers seat.

the MC8 was not offered with a lifting tag.......only a tag air dump...

not sure of reasoning of lifting or dumping the tag when it has rained alot while camping...this will only cause you to sink faster.

I found this out in Wisconsin back in Nov. when I got stuck in a sand volley ball court I was told was a parking lot (covered with snow)
when I raised my tag to get better traction I only sank deeper

[tekebird]

tires and earth surfaces?

Sand and Mud....you want as little weight  on the footprint...so dispurse the weight by having more axles or larger footprint tires

Snow........you want as little footprint as possible narrow tires or more weight on each tire


As a point of reference.......raising your tags is so insignificant that MCi does not have lifting tags any longer

[busnut104]

I installed a lift axle regulator and gauge it the drivers area, that way I have control when needed. I don't know if I would want to run very long with the axle lifted off the ground with no real frame??

[skipn]

  I want to thank all, I got some good ideas. For 90% of my needs it looks like dumping the pressure to the tags will do. The places I traditionally go to are uneven, at times rocky fairground fields. Getting stuck in my own back yard is one thing but in public and yes I probably will get stuck (again)

   Dumping the tag air on snow I am going to have to do some more thinking about. Traction versus handling. At 20 mph it may not be an issue but  over 45 mph could cause real work.

  The idea of being able to lift the tag still intrigues me. I will have to spend some engineering time on that one.

Thanks
Skip