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al perna · 10-16-2014, 08:45

Thanks Curt but, I don t this this is what is needed . This issue started just prior to the panhard bar replacement , I think there is a connection but need first to understand how it works .

Josams said it is only there to align the body with the axles , then why on turns does the frame go out of alignment ?

***patticake*** · 10-16-2014, 21:21

Actually, it keeps the axle from moving side to side. It may not be much but it can. Think about what is holding the axle to the frame, some air bags, some rods that go from the axle straight ahead to the frame and a panhard rod to keep the axle from moving left or right. Plus the shock absorbers. That's it. The rods that are parallel to frame and the air bags keep the axle from twisting up or down, at the pinion(where the drive shaft bolts to) depending on whether you are on the throttle or not and how much throttle you are giving from a dead start. The air bags also support the vehicle instead of a leaf or coil spring.

Now that I confused you enough, on the ends of the rods that go forward there are also bushings that can wear causing problems. These rods are also on your front axle.
The problems you are having need a GOOD frame specialist in heavy duty equipment. Check with some charter bus companies in the area where you are or where you are going. Most truck guys don't want to fool with a bus, cause nothing is easy to access.

al perna · 10-17-2014, 08:42

thanks Steve for the info. Actually I have come to understand all that you mention, as I deal with this issue over the past 4 months or so , not to mention various other suspension issues over the past 2 years .

lets take the pan rod in the rear . while sitting dump air , then air up all is straight and level . so one must say all is good ?

she measures and tracks true .

then we make a turn ,and the body is out of alignment with the axle. this issue surfaced after the old pan rod snapped and a new one was installed . I would think if the rod was not installed correctly the frame would not have lined up correctly in the beginning , but why would she shift on turns ?

***patticake*** · 10-17-2014, 09:28

I have to agree with you on this. It sounds like the panhard rod is doing something weird. If possible, get the bus over a pit and observe the rod while raising and lowering the suspension. It may give a clue as to what is going on, plus you have to have it removed and take a really close look at the bushings and the metal to see if it is flexing. Look for paint flaking. This will be a sign of a problem with the metal(in other words, the metal flexing or bending)
I can't remember if there is something similar on the front axle, but check there also.
I know it sounds weird, but until all the suspension components are looked at, we are just guessing. Maybe David can pull up some chassis specs and check for something that I'm missing. My degree is in automotive technology not heavy equipment technology Big Grin

davidbrady · 10-18-2014, 12:23

(10-15-2014 19:53)al perna Wrote: guys I continue to have a issue with my leveling . On a hard R turn she will drop hard L side . On the L turn she drops R side .

all air bags are new
ride height is 8"+-3/16
replaced panhard rod
replaced all HCV

the folks at Josams said they have no idea what the issue is .

all thought and ideas will be appreciated .

Al, should I split this out into its own thread or do you want to start a new one? This topic easily deserves its own thread; it's getting lost here. I suspect bad HCV's. You can swap the left to the right, and vice versa, to see if the problem follows them. I'm assuming the coach tends to lean in one direction, which may be totally wrong. A thorough description of the behavior would help, but this is going to be a difficult thing to debug on a forum. From the description so far, it could be suspension bushings, panhard rod bushings or bolts, wrong air bags, pinched air lines or other obstructions, faulty HCV's. There's nothing else left! Smile

***Arcticdude*** · 10-19-2014, 12:48

Al, tell us about the panhard bar breaking. That's definitely not a normal occurrance. In fact, other than yours, I've never heard of another. Bushings failing, yes. But never the bar itself breaking. Did you see the broken parts? Who did the replacement?

al perna · 10-22-2014, 21:19

John,

There is evidence that the Pan hard was rubbing for some time on the pumpkin of the drive axle. There is also evidence that the bar was bent . There were 2 times I had lost a air bag, and continued to drive till a safe way could be found to exit the high way .

the bar only rides a few inches above the pumpkin and the loss of air on one side combined with the bouncing ,broke the bar . when we removed the bar there was clear evidence the bar had previous brakes but had not completely broke thru .

I believe the bar is a overlooked component of the suspension system and could easily have damage . It is located at the top of the drive axle and should be inspected . I would look for the bar to be bent or a smooth underside where it rides above the pumpkin ( Halloween ) is around the corner Smile

davidbrady · (This post was last modified: 10-22-2014 22:09 by davidbrady.)

Back in 2004 when I bought my LXi I took it to the factory for service, (yes... remember those days??? Smile

). Wendell suggested I replace the panhard rod on the drive axle with a solid bar. He said he's seen too many of the hollow bars break on LXi's. I imagine it's the extra weight that the LXi carries. With Al's bus, the addition of the Goldwing may have contributed significantly to the load bore by the drive axle further contributing to a panhard rod failure. It's essentially a two-force member responding to only tension and compression; the more material there the better.

al perna · 10-23-2014, 08:22

there is no doubt the wing is heavy . when the bar initially broke the wing was on the back, and we were able to drive aprox 45 mph without the roll over that accompanies the broken pan=hard bar . when we needed to drive on the same road back to a facility that would make the repair, the bike had been removed . I was unable to drive on the high way. and needed to work my way to there garage by way of back roads . There is no doubt about the increase in load to the suspension the bike creates .wouldn't the bar only be needed to off set the body from rolling ? so a force in a turn of great speed would be increased by the weight of the bike , but I don't see how driving down the road with the bike has any effect on the bar . am I missing something ?

davidbrady · (This post was last modified: 10-23-2014 12:36 by travelite.)

Yes, you got it Al. The panhard rod is there for lateral location of the drive axle; the four trailing links are there for longitudinal location. In a right turn the weight of the coach pulls on the rod and in a left turn the weight pushes on the rod. On a straight smooth road with no side winds, the rod isn't doing much. On a bumpy frost heaved road the bar is doing a lot, even when going straight. These conditions lead to lots of one-wheel-bump. When one side of the axle is lifted or dropped then forces are applied directly to the panhard rod and into the coach body. This is why stick axles located via panhard rods mounted high above the axle tend to ride rough on patchy surfaces - the road upheaval is being transmitted directly from the axle into the coach frame and body via the panhard rod, bypassing the air springs. So on a straight, but bumpy, or crowned, or windy road there can be a lot of forces on the rod. Also with the bike hanging way off the back your rotational moment of inertia just got bigger so the tugging and pushing on the rod has grown even larger. Without the bar in place, I probably wouldn't drive the coach, doing so puts big stresses on components that weren't designed for it.