When Lifting the Bus--Always raise the Tag?

[tdelorme]

Larry, jacking the front of the bus without raising the tag will overload the tag axles. I have raised my tag while moving slowly a lot of times. If the proper procedure is to stop, raise the tag, move the bus, stop and lower the tag, I've been doing it wrong. I think as long as I don't know for sure I'm doing it wrong it will be ok

[Jon Wehrenberg]

These buses are not fragile and the precautionary information likely was written because someone was only understanding part of the story.

First, even though I have a 45 foot coach I never raise the tag. I don't care how sharp the turn, I just don't raise the tag. Here's the rest of the story.

I happen to have a coach with the Prevost installed "stabilizators" which automatically deploy hydraulic supports to keep the rear from dropping while simultaneously dumping air from the tag air bags when my steering wheel is turned to the extreme in either direction. It is all automatic. A few of us on this site have the system. Some converters ordered coaches without that system, and others disabled the system. Prevost does not support the system any more. I don't know why because it works great.

When you make a sharp turn the tag tires scuff, and the turn radius is not as sharp as possible. That actually doesn't hurt anything although it does put side loads on the tires and tag axle suspension. So despite the instructions saying not to lift the tag when moving, that is what you should do if you are in a very tight spot. What you need to be aware of is that the rear of the coach is going to drop. You need to determine before you lift the tag if the rear settles is it going to drag or drop down onto something? But lifting the tag at low (walking) speeds does no harm. I would suggest not getting into the habit however because in the uneven ground of some campgrounds lowering the rear of the coach could result in damage, especially to the rear flap, the exhaust, or even the oil pan. When you do things by force of habit you can encounter unintended results.

I view lifting the tag as a "get out of jail free" card. Use that feature if you have misjudged a turn and now you need every bit of help you can get to tighten the coach turn radius to avoid unhitching the toad so you can back up. I would never consider lifting the tag on city streets or other places where making tight turns. Any misjudging of the turn, especially if the drive axle hits or goes over a curb could result in damage because the tail of the bus has dropped.

If the coach is being lifted, it is likely it will be lifted by jacks under the steer and drive axles. I have seen Prevost lift countless coaches this way and have never known anyone at Prevost to raise the tag prior to lifting the coach.

[truk4u]

Jon,

I had my 1st visit to Prevost Jax in January and they used a lift that lifted by the jack points and not the tires. I was asked to raise the tag before the bus was lifted.

Na na na na boo boo....

[Jon Wehrenberg]

That's a first. I have never seen that. For 19 years all I have ever seen was Prevost using the lime green lifting jacks under the tires to lift the bus.

Now answer the question.........what did lifting the tag accompish? the tag axle limits are not defined by the shocks like the front end, but by the lifting chain.

[tdelorme]

That's a first. I have never seen that. For 19 years all I have ever seen was Prevost using the lime green lifting jacks under the tires to lift the bus.

Now answer the question.........what did lifting the tag accompish? the tag axle limits are not defined by the shocks like the front end, but by the lifting chain.

This cast a shadow over every single bit of Jon's advice. The lifting jacks at Prevost Texas are yellow, not lime green. Now we have nowhere to turn.

[dale farley]

Because I forget after a couple days, I was reviewing my CC Users Guide again yesterday, and they reitterate what Prevost says. "The tag should always be down for normal operation, but with the tag up, the coach is able to manage a tighter turn diameter which is a convenient feature in city driving. Also, when driving in icy conditions, raising the axle up will increase the weight on the drive wheels by approximately 9,000 to 11,000 pounds, thus, providing more traction.

I almost always lift my tag when making a 90 degree turn. But as Jon mentioned, it is easy to make a mistake. While in Wyoming last year, I turned into a campground where the entrance made a dip. I removed my tow connection and damaged my mud flap simultaenously. The other disadvantage I see to lifting the tag, is that I easily forget to lower it when in a campground.

Yes, I have a light and an audible tone that tells me it is up! I don't forget to lower it while making turns on the streets, because I never remove my hand from the switch until I have moved it back to the correct position.

While in Marion, NC last month, I raised the tag while making some 90+ degree turns. Ed mentioned that he thought the rear of the bus looked a little low when I came in, but I hadn't noticed this while sitting in the driver's seat. When I parked, I noticed my level system didn't do as it should. Finally, I noticed the noise I was hearing telling me the tag was up.

But, I will still raise the tag when maneuvering sharp turns.

[Joe Cannarozzi]

Jon I would like to disagree with you on those lifting chains.

When the tag is in the down position there has to be more slack in the chains than the full travel of the tag axle or they would impede its travel in extreme circumstances.

Those lifting chains can only limit the movement of that axle when they are being utilized otherwise it is the shocks that limit full travel just like the steer.

Another example. When in level low if what you suggest is correct those lift chains would become taught before you could get all the way up in the rear and I am sure that is not the case.

If the chains are set correctly there will still be just a slight amount of slack in them with the suspension fully extended.

I still hold my opinion that raising it prior to jacking it is suggested to keep unnecessary strain on the shock eyelets.

[BrianE]

I recently had a failed diaphragm in the tag lift actuator. After replacing it I was careful to maintain the original chain tension so that it had a slight amount slack with the tag hanging on the shocks. Additionally, when having mtc done at Prevost Jacksonville and Mira Loma, the tag was lifted before lifting by the frame.

[lonesome george]

We are constructing drive on ramps to raise our coach servicing and such, the height of the ramps will be 8" (approach angle 14 degrees) and will be long enough to support the drive and tag axles and separate ramps will be available to roll the steer axle on, I dont't plan on using them this way every time, sometimes front only or rear only.
My question is should the tag be raised when the coach is being backed on to the ramps?

Side note: Weighted the bus the other day with full fuel and water tanks and this is what we have.
Steer 13,800# rated @ 16,500
Drive 20,440# rated @ 20,400 over weight by 40 lbs
Tag 11,320# rated @ 12,000

[dalej]

Quote:
Originally Posted by Jon Wehrenberg

That's a first. I have never seen that. For 19 years all I have ever seen was Prevost using the lime green lifting jacks under the tires to lift the bus.

Now answer the question.........what did lifting the tag accompish? the tag axle limits are not defined by the shocks like the front end, but by the lifting chain.

Quote:
Originally Posted by Ted DeLorme
This cast a shadow over every single bit of Jon's advice. The lifting jacks at Prevost Texas are yellow, not lime green. Now we have nowhere to turn.



Well this should add a bit of a spin on your recollection of truth!