[Richard]

I used three different names for the same thing since I learned that different industries and shops call the same thing three different names. It is the rod that runs parallel to the drive axle, and it’s purpose is to keep the drive axle centered in the frame. After all air bags are somewhat mushy. 

Mine was worn out, so Covid madness finally spurred me to replace it. Getting it out is not for the meek. Big torch and bigger hammer to get the tapered fitting to unstick. You can’t really tell how sloppy the ball joint is from the photo, but it has about 1/4 inch play in it. 

The impact of wear in this part is that it would allow the back end to wiggle a bit, now that’s normally a good thing  , but anytime the back shifts, the driver must compensate for that movement. It will be a couple of weeks before I can drive it to see if I can detect an improvement. 

Anyway, the replacement part is Meritor Kit 5116. You can find alternates on the net. Keep in mind the original and the replacement are welded together to form one non adjustable rod. I am posting because it took me almost a week to identify and find this part. 



Here are some pics.
   
   
       
   

[Richard]

So......... I finally got to test drive the coach today after replacing both the panhard bar and the tag axle bushings. I am a happy camper.

Some of you know my OCD nature about how the coach handles. Let me start with the coach was NOT driving badly. Most situations were easily one handed and relaxed but there was still a handling phenomenon that I did not understand. The behavior was best characterized by the amount of back and forth movement of the steering wheel to keep the coach centered in the lane. On a flat smooth road with little wind, the coach required a slow back and forth of about an inch to keep it centered. BUT, if the road were heavily crowned or there was a consistent side wind, I barely ever moved the steering wheel to center the coach. Obviously if the coach were preloaded to one side, whatever sloppiness that was causing the slow back and forth was taken out of the system. Also, I felt like I had more movement out of a passing semi than I should.

One more interesting observation was the amount of steering input required when the road changed from a positive to a negative camber. Before the replacement of parts in the rear suspension, that change was about 2 inches of steering wheel movement when transitioning from a right cambered road to a left cambered road.

I have been working on front end suspension improvement for five years, but sitting behind the wheel for thousands of miles thinking about what could cause what I felt, at least forced me to consider that the rear may be driving the front. I reasoned that if the back were moving back and forth relative to the center line of the coach then the coach would naturally change direction ever so slightly.

Today was dead calm, I 75 is a smooth and lightly cambered road, and the steering correction was dramatically reduced from what it was prior to the rear suspension work. It would have been nice to have a test drive after the tag axle bushing replacement and a second drive after the panhard bar replacement, but other issues prevented that. I don't know which one of the fixes or both are responsible for the improvement. Also, the change in steering wheel position when the road camber goes from right to left is now less than an inch.

Did I say I was a happy camper?

[HoosierDaddy]

Happy , Happy, Happy!!! Excellent write up. Now I’ll be more aware of how my Newell handles..

[Richard]

Dean, I believe you have a straight axle in the front. The straight axles on air bags also have the panhard bar, although I don’t remember it being exactly like the one I posted. If the panhard bar is sloppy on the front, that would produce a lot of wandering.

[Richard]

I just wanted to do a longer term report on the impact of changing the worn out track bar, and the worn out tag axle bushings.

We are three thousand miles into this trip, and I can say without a doubt that one of the two repairs above corrected my nit picky handling issue. The issue was that I always felt like I was doing a very slow zig zag down the road. A minor correction to the right would always require the next correction to be to the left. This was most pronounced on a dead flat and smooth interstate with no wind. Back and forth, back and forth, back and forth. The coach would drive without this back and forth under two conditions. The first was if the road were heavily crowned, and the second was if the wind were blowing gently and consistently from one side or the other. I always felt like the rear end was steering the front end.

Another clue that the rear end was moving around was the push I would get when a semi got his nose just on my rear I would sense the coach move to the right so I would have to steer left to keep from crossing the center line.

Those issues went away with the replacement of the track bar and the tag axle bushings.

Don’t get me wrong, I still have to steer it, but I don’t have the rhythmic wander doing down the road any longer. An added bonus was the coach is much less of a handful in high winds than it was.

[ccjohnson]

Glad you got it fixed Richard. The rhythmic right & left motion might induce highway hypnosis if you're a bit fatigued.

[Jack Houpe]

I know now what a panhard bar is!

[[email protected]]

Thank you for quick response. I found it at Finditparts.
James Price³

[khgeisler]

I just can't believe how timely this post showing up is.  I have my rig in the shop for a few things and asked them to look at the steering.  I just forwarded them this post to have them inspect this as well.  Perfect timing.  I wish I had a place to work on the real guts of my rig.

[Richard]

Karl,

Take a good look at the tag axle bushings while under there.