[Richard]

My comments are specific to the Dana Kirkstall IFS 84 suspension used from about 96 to 03 or so. 

The interstate handling of my coach had deteriorated resulting in some wandering at highway speeds. I don't like that. I suspected either steering gear box adjustment or toe in. 

I learned a few things in the fix that I thought I would pass on. 

The first is the adjustment of the steering gear sector screw. This adjusts the tightness of the steering gear box. Loose results in sloppy steering, and tight results in an evil beast. Tight means that for every small correction at highway speeds you have to make a correction in the other direction to cancel the first since the steering will not recenter. 

The best way to set the steering box is off the coach. The second best way is to remove the drag link arm and use free play in the pitman arm ( the square one attached to the steering box). You adjust the box until you feel free play in the pitman, then slowly tighten the screw till the free play is gone. It works, I've done it that way on other coaches. But you have to remove the drag link to do this, and that can be difficult. I could not get the drag link off. Of course there is always trial and error, but the changes are so subtle that it's easy to get lost. The worst way to adjust the box is to run the screw in until it feels snug. It will almost always be too tight if you do it that way. 

It occurred to me that there may be a third way of adjusting the box. I did this exercise with @77Newell help. The concept is this: using a dial indicator placed on the pitman arm, turn the steering wheel a set amount from right to left and measure the movement of the pitman arm. Less slop in the box will result in more movement at the arm as the box moves from right to left. 

Here is what we did.  Make a template to go behind the steering wheel, and go about 4 inches either side of the center and make a mark. Put tape and a mark on the top center of the wheel. In the straight ahead position the wheel should be centered between the marks on the template.   Mount the dial indicator base on the coach frame, and the dial indicator on the pitman arm. The front tires should be off the ground to make this easy. Of course, chock the coach for safety. 

Back off on the adjustment screw about a turn. Now have the steering wheel operator turn the steering wheel to the right mark. Set the dial indicator at zero. Turn the wheel to the left mark, and record the movement on the dial indicator. Tighten the screw 1/8 turn and repeat. You will find that with each tightening the movement will increase slightly. UNTIL you have removed the slop, then you will notice that amount of movement at the dial indicator does not increase with an increase in the adjustment screw. Put the adjustment screw at that sweet spot, and back it out about a 1/16 of a turn. 


I really learned something interesting when I started playing around with the toe. I don't have a fancy alignment machine in my drive so I use the old school trammel for checking toe. I won't bore you with my miscues on this one, just the interesting learning. 

I found that the toe I set with the trammel was significantly different in the static condition than in the dynamic condition. Huh? When I set the toe with the coach stationary, the toe would change if I rolled the coach forward. That kind of makes sense in that the toe adjustment can vary as the different forces take up the slop in all the suspension components including tie rod ends. I had set the toe at 3/16 in, but when I checked it after rolling forward, it was about 1/32 toed out. The coach definitely had the wanders at this setting. I spent the afternoon driving up and down the local interstate, stopping at rest areas, and using my trammel bar until I got the toe set at 3/16. The point is this, if you check the toe, ensure that the coach has rolled forward for twenty feet before you call it money. I don't know if this phenomena would occur on an alignment rack or not. 

I had an alignment done two years ago. I did not see the printout, but took the tech's word that the toe was set at 1/8. The coach drove OK and did not wander. I suspect that the change in toe was due to a change I made in the front ride height. I raised the front ride height when I installed the 365 tires to give a little more clearance to the fender skirts when making tight turns. As I look at the front end design it is clear that when you change the ride height on the IFS front end that you will change the toe. There are three tie rods on the IFS. The one in the center is mounted to the frame, it is connected to a right and left tie rod which are connected to the right and left steering knuckles. When I raised the frame relative to the tires, I essentially shortened the tie rod structure. Since the tie rods are behind the tires. I pulled the rear of the tires in and pushed the front of the tires out. Why didn't I notice right away? Cause it was one of the things I did while parked in Florida for two months. I am sure if I had raised the ride height and driven immediately afterwards the light bulb would have come on. 

I hope this helps you if you are OCD about steering like I am.