Suspension air pressure adjustment

[twinboat]

If the driveshaft has been removed and re-installed improperly, it will vibrate.

You can visually check that the ends are in phase.

[twinboat]

A better shot.

[bneukam]

Not saying it’s your driveshaft, but when having any issue you describe the first thing to check is your ride height. Not visually but knowing exactly what the measurements are and where to measure. Doesn’t need to be off by much to cause problems.

[Smitty77]

How about have you had the chassis/axle alignment checked, all axles? Part of this, includes setting to factor spec road height...

Possible your front end Road Height is on the top, or over the ride height's high range?

What were the new shocks you went with, as other info sharing?

And some pun intended, hang in their... The coach is capable of providing a very satisfying ride, it's just getting to, and correcting, the root cause of you your problems.

Finding a competent chassis shop in your area, would be worth investigating. Or, go to Florida on a trip to Jossam(SP?, or California to Colton Truck, or Oregon to Carrier & Son's (Believe that is the go to shop in Eugene/Junction City area(?) - they all have great reputations on chassis alignment, and debugging of unusual problems...

Best to you,
Smitty

[wsmcycle]

I put Konis on all six positions. The ride is much more stable and they lessened the rear bouncing "some".
Both sides and front and rear (axle and tag) bounce about equally.
I will check the drive shaft to confirm the rotation of the U joints.
I do not know the correct ride height or the points to measure it from. Perhaps if the ride height is too low it is bottoming out or if too high it is hitting the top. Is that the result that occurs with incorrect ride height?
My thinking at the start of this thread was that the bladders might be too hard (over-pressured). for example, say the supply pressure is 120psi and the lifting pressure needed for the bladder is 100psi. When the valve opens, the bladder lifts to the new height. If however, the lift pressure required is 130psi then the 120psi supply will not raise the bladder and in fact, without a one-way valve, the bladder would deflate.

[wsmcycle]

""Finding a competent chassis shop in your area, would be worth investigating.""
I am in central US. Fort smith, Arkansas. I would certainly like to locate a good chassis shop. Kansas city, oklahoma city, Memphis, dallas?????

[bneukam]

Hopefully somebody else will chime in here to help you on your ride height specs.
Only familiar with 02 and older coaches. On those the front end does not have a range, but a set height and either too low, or too high can cause bouncing.

[twinboat]

Originally Posted by wsmcycle

I put Konis on all six positions. The ride is much more stable and they lessened the rear bouncing "some".
Both sides and front and rear (axle and tag) bounce about equally.
I will check the drive shaft to confirm the rotation of the U joints.
I do not know the correct ride height or the points to measure it from. Perhaps if the ride height is too low it is bottoming out or if too high it is hitting the top. Is that the result that occurs with incorrect ride height?
My thinking at the start of this thread was that the bladders might be too hard (over-pressured). for example, say the supply pressure is 120psi and the lifting pressure needed for the bladder is 100psi. When the valve opens, the bladder lifts to the new height. If however, the lift pressure required is 130psi then the 120psi supply will not raise the bladder and in fact, without a one-way valve, the bladder would deflate.

A driveshaft out of phase, or at an improper angle, will cause vibrations.

Diesel pushers have short drive shafts, making rear ride height so important.

https://youtu.be/Idk3BVDVHq4

[bneukam]

What is the correct ride height?
http://www.irv2.com/forums/showthread.php?p=4540760

Here is a recent thread that may help you. Ride height is the most important info you won’t find in your manuals.

[Smitty77]

If those were EVO 99's Kong's, then shocks should not be an issue. If they were the Adjustable SP3 generation, I'd make sure the front/steer shocks were at least on level 3, maybe 4. (If doing it yourself, I'd go with 3 to see how it helps control rebound and non porpoising. If paying someone, I'd go with level 4, and if it your comfortable with the ride at that setting, leave it at 4.).

When gettin the all axle alignment, and height levels reviewed by a competent chassis shop, they should be able to adjust the Koni's for you - IF adjustable!

The SP3's are more robust the the SP1's and 2's - but that is still a lot of coach on an IFS front end!

Best to you,
Smitty