Tag axle

[PeterH-350LE]

Originally Posted by davejay

.. I think they set it up this way to insure the tag doesn't get overloaded. I often wondered why they didn't put the valves on the drive axle. Then the tag would just stay planted . ...

I think you nailed it, the more the rig gets loaded the more the airbags get adjusted by the tag axle position, to keep the extra load of the weight limit tag axle. Running the bags to high takes too much load of the tag axle and you may as well take it out and just run on the drive axle.

As soon as you raise the vehicle with the leveling jacks, the air gets dump, supporting the theory. At least my 345 operated that way. My 280 and 310 had a total different system with the leveling valve(s) mounted to the frame and drive axle

My understanding is to adjust the heigths under normal load conditions to appr 9.5-10"

[Hans 34.5]

When I put new front springs in it lifted the front loading the tag and that brought the rear up. When it had the old front spring and no front air bags the rear was sitting low as the front was. I would adjust the rear until you get it to spec.

[bkahler]

Here's an excerpt from the 84-86 325-345 service manual that details the air ride system. It's four pages of information.

325-345-air-ride-service-information.pdf

Brad

[Smartstream]

It is interesting the use of two valves and yet the bags are connected with a tee. If the coach was driven on a high crown road the coach would lean to the low side and the low side valve would add air while the high side valve would be releasing air. Obviously this is not a normal situation but depending on the crown of the road, the amount of coach lean, and the amount of valve arm travel before air is released it makes me wonder why. By simply removing the air line between the two bags and connecting the low pressure sensor to the air tank the issue is eliminated.


It also states it is normal for the pressure to drop if the coach has not been used for a few days. This condition would lower the coach on the drive axle and place the tag axle in an continuous overload until the ignition is turned on to start the compressor.


Maybe I'm missing something but it just seems strange, not that Airstream has never done anything before.

[Kreimer]

Round three! Got her back (again) with the air hoses hooked up properly and height set properly. I have decided that the tag does not help the ride one small bit. It rode way smoother when the airbags were over pumped. That said, it still rides loads better than before the replacement.

[Smartstream]

Also interesting that the shop sends it out without verifying that it actually works or checking for proper adjustment. Maybe I just expect too much.


Glad you got it installed and functioning.

[Kreimer]

I had to tell the tech what to do. Grrr. Apparently a weird system in this beast. Idiots. Unfortunately they are the only people in town that will work on this thing...

[bobmiller1]

OK, now that you have got the hard part mostly done, now you have to fine tune it. You need to go to a weigh scale now. Roll the tag axle over the scale first, only the tag axle. Get that weight and mark it down on a piece of paper. Next roll the front steer axle only on the scale, mark that weight down, now roll the whole motor home on the scale, you will now have the weights of all the axles. I suspect you still have an issue with the drive axle suspension. It appears to me that you have someone else doing the work for you, are you not able ??? Or are you not sure of what you’re doing. Post a couple more pictures of the wheel well opening, I would like to see the top of the tire clearance to the opening. If you want to PM me feel free to. Regards, Bob

[Kreimer]

I will try to get some pics of the clearance tomorrow when I get her on level ground with the bags aired up. I have other people work on it because I have no place to do the work other than the busy street beside my house. Where we are in the cave has no electric nearby so I can't do it down there anymore... My rear air is now giving me fits. gonna pull the cover off tomorrow evening and check for mud daubbers..

[wimpy]

Originally Posted by Isuzusweet

The only thing you can't get for the new tag are the brake drums, as there are none available; officially unobtainium.

There a lot of tags out there that are well past their prime and need replacement.

Forgive my ignorance:
What indicates a tag axle that is past its prime?
Are the internals of the tag axle special?
What alternatives would I have if I needed new brake drums?
Would an axle that Dexter makes not work on my 345?

[PeterH-350LE]

Originally Posted by wimpy

Forgive my ignorance:
What indicates a tag axle that is past its prime?
Are the internals of the tag axle special?
What alternatives would I have if I needed new brake drums?
Would an axle that Dexter makes not work on my 345?

I can think of 3 scenarios that would deem a tag axles to be junk:
1. Hardened rubber in the axles tubing. Tag axles are just modified trailer axles and suffer from the same relative short life span. Check the position of the arm with the spindle on the end. Under load, If the spindle is lower than the tubing the axle is in new condition, if its above the tubing the axle is trash.
2. Cracked mounting brackets. This happens when the tag axle gets overloaded from improper towing (nose up). I suppose a good welder could fix it
3. broken spindle

[davejay]

Hey,
I was looking at your picture, you need to see just the top of the tires. I got mine right at the point where the lip of the wheel well is about a1/2 inch lower than my tires. My airbags at this height, put the end of the spring about 5 inches from the contact point on the body. Looking at my bag bottoms, I got about 3 to 3 1/2 inches of cone . Haven t weighted it yet, but by the look of the tire spread at the road I'm pretty close to having the tag where it supposed to be. The tag does have weight on it. And it should look pretty much like the duals. If it looks like it's low on air, check your air pressure. If good, you may have a little to much load on the tag. That may explain why it rides rougher than when the bags were up higher. The. Ride height is a pretty good indicator, but not nessessarily the law. Like Bob says, now you got to fine tune it. This thing should be very smooth going down the road. DJ

[Kreimer]

I got her out on the road today. When I got home I was able to get a pic of the aired up system. The top of the tires on the drive axle are almost level with the top of the wheel well opening. I have included a pic. Hopefully you can see it ok.

[Kreimer]

[Kreimer]

this is the distance from the spring end to the frame. It does show some impact marks from where it was hitting the frame previously.

[davejay]

Hey,
In looking at your bags, see the bottom of the bag where it makes the bend on the cone? That splitting is dry rot. That's where they blow out, if your lucky, they'll start to leak there. Not trying to scare you, but it is something you may want to address soon. With my tires just at the edge of the wheel well, I got 5 inches of travel on the bags, before they contact the body. Your pics make it look like about 3 inches. That may be the harder ride issue you got. More air, more travel, softer ride. That's the fine tuning bobs talking about. If you got a little higher in the back, that's ok. Find the sweet spot for ride. I think you could take it up an 1 1/2 inches an be good. That amount of rake isn't going to affect drivability as in caster decreased. Your close. DJ