When Lifting the Bus--Always raise the Tag?

[LarryB]

My Converter supplied "User's Guide" manual states in a 'Caution' note that " to prevent damage to the suspension, always raise the tag axle before lifting the coach". There is another 'caution' note that states, "Never raise the tag axle while the coach is moving".

I am not disputing these cautions-- I am looking for clarification as to just what damage can occur and how does one maneuver in tight areas, do you stop to raise the tag? How about lowering the tag.

I checked the Prevost "Owner's Manual". I states basically the same thing.

As an aside, I have been at my coach when it was raised twice and jacked once, and I don't recall anyone ever raising the tag prior.

My fault I suppose, because I'm just now getting into the manuals

Thanks for the info

[Joe Cannarozzi]

When your bus was raised was it lifted from the tires or the frame?

[LarryB]

Joe, Lifted by the tires, and jacked at the jack points.

[Joe Cannarozzi]

This is purely a guess but we have discovered that the full travel on the steer axle is limited to the maximum extension of the shocks. Folks were experiencing snapping off the eyelets on shocks and so Jon went and removed some and discovered that with the shocks off the axle had even greater travel.

If this is the case on the tag as well, lifting it would eliminate any unnecessary stress on the tag shocks I suppose it would be a safer way to lift too..

I have an older bus and am in no position to speak for Prevo but I can tell you if I ever had a reason to lift the tag and continue to a destination for whatever reason, I would. I personally have not had to but I know others have.

[LarryB]

Thanks Joe. I have routinely raised the tag while in motion to maneuver around tight spots where I felt the tag tires might scuff or scrub the tread. I guess I was doing the wrong thing.

[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....:D

[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.:rolleyes:

[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.

[LarryB]

So----IF you raise your tag, does it clear the ground--how much? Mine just basically unloads the weight and will still scuff the tires. It may be off the ground but really hard to tell without having someone try to slide something under the tire.

[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

[Jon Wehrenberg]

Gentlemen,

Your lifting chains may be slack, but mine are tight when the bus is raised on the air bags. Think about this....which would you rather have limit your tag suspension travel...lifitng chains designed to lift and support the tag axle, or the eyelet of a shock absorber? No need to answer. We all know which is correct. That may not be the way the chains on various coaches are adjusted, but it is the way mine are and I am glad. Now the only shocks I can break are the steers.

Larry,

Unless the coach has a very heavy rear when the tag is lifted, given enough time the coach will eventually return to ride height and the tag will be a few inches off the ground.

That is dependent on the tag lift diaphraghms being in leak free, and the ability of four air bags to lift what six usually do.

[gmcbuffalo]

Those shock pins are like $48.00 apiece, I just bought some to put the extra shocks on the front. I put the medium shock for an XL on, the previous owner put the white XLV transist shocks on. I have never been able to lift the front high enough to get Jon's 13" stands under, just shy of 1/2" to do so. So I think the stiffer white shocks have a shorter travel length.

A few years back I was trying to get into Hill AFB and they had a real strange design to the terrorist blockage, I couldn't make the turns. They opened a spot for me to turn arounds in and I lifted the tags to make the turn to get out, they weren't letting me in.. About 2 miles later I realized I still had tags up so I let them down while moving, . As it was I was close to my daughters house and they came out to see us drive in. As I got out of the bus she said a big bolt fell off the bus. Out in the street there was a big bolt about 6-8 inches long in the street. I had busted the threaded bolt off the lifting bellows, both side. So I do know you want to watch your speed while droping the tags while moving`

GregM

[LarryB]

Seems I recall CC Motorhomes, and probably many others, have a design on the tag that would lower the tag at some very slow [20 mph] speed if the driver had forgotten to do so and exceeded that speed as the coach started to accelerate

[truk4u]

Hey Mel, the famous A-1 got you on this one!:(

4735
I think you would call these Lime Green supporting Ms Truk!

Mel "0"
Jon "1"

[Jon Wehrenberg]

I owe you one Truk.

[tdelorme]

Let me think for a second here. What would JDUB say under these circumstances.
I'm sticking to, "they are yellow in Arlington."

[Jon Wehrenberg]

Where's the proof? My new best pal Truk has proven what I said.

I half expect one of the dynamic duo to photoshop Truk's picture and make those jacks yellow.

[Denny]

Lime Green in Prevost in New Jersey also

[tdelorme]

Lime Green in Prevost in New Jersey also

Gee thanks, Denny. I love getting thrown under the bus. 1-800-ACME

But, back to the picture. Jon is right, "where is the proof."
That looks like Stewart & Stevenson's shop, not Prevost Nashville.
Prevost's techs wear a different uniform than the one in the picture and that guy is awake and up on his feet. Prevost techs, well use your imagination.

[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!

[Jon Wehrenberg]

Dale,

Tell me you did not photoshop the red colors.

[Gary & Peggy Stevens]

Dale, Tell me you did not photoshop the red colors.

Jon, I know Dale didn't photo shop the Red Colors on the Jacks, because that is what Dallas uses, however, he did photo shop the coffee mug, cause it was originally a can of beer in his hand. :D

Gary S.

[tdelorme]

Dale, look over your shoulder and you can see the yellow lifts of which I speak. OK, so they are a real light yellow but a shade of yellow none the less.
I just called S & S and all their shops use lime green lifts. Apparently we have members who think they are at Prevost when in fact they have pulled into S & S. No way to tell from the invoice either as both will cause immediate heart failure.
We need to get Hector in on this discussion. He has spent more time at Prevost in Arlington than all of POG combined. Did they ever get it right, Hector??

[0533]

Here we are at Prevost Car Quebec, they use 2 Hydraulic jacks at 4 jack points, not tires, always tell me to raise the tags when they are lifting the bus. Same setup in Jacksonville.

[truk4u]

Dale,

I'm in shock!:eek: The master of vintage buses visiting Prevost!:rolleyes:

Jan must have made you do it....:p

[Joe Camper]

Let's rejoin this thread and clarify.

The tag axle has the ability to overextend itself and damage things given the right conditions.

This is why they say to lift it when lifting the bus.

If a shop uses the portable lifts that go under just the drive and steer axle and the suspension is at ride height as the bus clears the ground the drive axle height decreases and the ride height valve calls for air. With the tag unsupported it takes on full air pressure with no resistance and things begin to bend and brake I've seen this type damage on more tag axles than I can remember.

Same with ramps. Unless ramps include both rear axles and u pull up with just the drives same thing will happen the tag will overextended potentially damaging things unless u lift it first.

On a side note when the bus is at ride height there should be slack in the lift chains.

[Gil_J]

I was asked at one shop to raise the tag after steer and drive lifts were in place. There's far too many industry professionals saying a tag axle that's not supported shouldn't have their bags inflated to question their expertise.