Spring Air Leak Shakedown.

[Joe Cannarozzi]

I am aware of more than one semi dump trailer manufacturer that uses a strap around the axle housing to keep it from extending past a given point.

[Orren Zook]

Joe & Jon are correct in their description of air suspension operation, I have customers who have modified their air suspension by welding a chain between the axle and a crossmember to limit downward travel to something less than shock length. I sell dozens of shocks every year to those who don't do this. Suspension manufacturers rely on the weight of the vehicle to keep the bags within their operational lengths when the tires are on the ground. I doubt we could see total bag travel unless trying to level the coach on very uneven terrain. Empty trailers as Joe described, especially those with spread axle suspensions will often lift an axle completely off the ground under certain conditions.

[Jon Wehrenberg]

I would like to give Ken some comfort, but there is none to be had.

I not only got 3/16" additional travel just be removing the shocks and letting the suspension drop because of its own weight, I could easily push down on the brake disc and flex the suspension down further. Imagine how much further it would go if it was the weight of the bus twisting it.

In the rear the radius rods that hold the fore and aft movement of the axles go over structural members and when the suspension is at its limit they actually hit the cross members to limit travel. I did not check to see if the shocks in the rear would break before the suspension reached the limit of its travel.

One thing besides the lack of a mechanical stop on the steer axle surprised me. Our buses which are sensitive to camber have a constantly changing camber as the bus oscillates up and down over bumps. With the radius rods at the bottom and a third one at the top of the axle, the camber changes as the axles describes an arc in its travel. It describes a similar arc sideways as well although the dimensional chages in either direction are minimal.

[dalej]

I have never had an issue with the back shocks, I don't think the back of the bus is subject to the bounce that the front is.

I still support the axles each time I remove the wheels though, I just don't like them hanging from the shocks.