Alignment Issue

[o1marc]

Member Slummieschap has messaged me with a question:
"I have a 2001 International FE 3900 School bus conversion, 40' Roughly 183,000 miles on a DT466 with a Allison MD3060 - the bus veers to the right and its most troubling when on a straight road and I have to constantly veer it straight. Sometimes its takes a while to get the steering back straight"

Most likely an alignment issue that can be aggravated by worn tires, improper air pressure, etc.
Is there a lot of play in the wheel before the wheels move?
Thoughts from others?

[slummieschap]

no play in steering before turning - pretty responsive in that way - the bus drifts and its hard to get back control of the steering - causing me to ASMP (almost s_IT my pants) while driving!!!

[Brad_SwiftFur]

My very first thought would be to check the tire pressures - minimum 90 PSI for 22.5" tires, max of 110 PSI.


Next, now that you've checked the tire pressures, is to make sure the wheel isn't loose, the nuts are tight. Still all good so far? Next thing is to check the steering rods and linkages, ball joints, etc. Should be no slack. Next up, jack up each tire, check for loose wheel bearings. Also check for slack in the kingpins too (this is the "hinge point" for the steering assembly). Check the springs, attachment points, hangers, shackles, etc. (I wouldn't be surprised if something here was broken).



If everything so far checks out, it may simply need a good old fashioned alignment.

[banman]

Originally Posted by slummieschap

no play in steering before turning - pretty responsive in that way - the bus drifts and its hard to get back control of the steering - causing me to ASMP (almost s_IT my pants) while driving!!!

Brad gave you a great list to check.
When checking that list after jacking up a front wheel -- grab it at 6 & 12 and 3 & 9 o'clock to feel for play. 6&12 is wheel bearings/ 3&9 is tierods,

Is this bus new to you? Was it driving okay before and suddenly it's trying to kill you?

Verify both front tires are the same size.

[Sehnsucht]

Brad has the exact right plan of attack. I would also ask the OP-by-proxy is the symptom most common if the road is canted or if there is a good amount of wind? It sounds like curves aren't the problem if it happens on straightaway but there's also some responsiveness to body roll in these types of vehicles, especially solid steer axles in contrast to independent front suspensions. I fight riding the shoulder all the time in my semi and the most common culprit is a crown in the road or a strong enough cross wind that wants to push my condo sleeper around. Skoolies aren't as tall but they're still big wind catchers compared to cars,

[cadillackid]

all 3 of my busses had drift / loose steering.. now all are either tight or in process of being.


1. Carpenter - prior to getting new tires it had mismatched brands on the front.. definitely made for a less than ideal drive as the trads were slightly different.. new tires with balance.. definitely helped.. next was its alignment was way off.. I had it algined and better.. 3rd part was the steering box lash was bad.. I had a lot of play in the box itself.. noted by jacking the front end up and pushing the wheels back n forth i could see the pitman arm move quite a bit.. adjusted the steering box tighter.. now she drives like a new bus.. steering is so tight now i tend to over-correct on the road as i was used to it being loose..



2. Red Bus - alignment was out.. had it aligned when I got new steer tires.. second part was a spring shackle bushing wasnt installed correctly.. allowed the spring to have some movement in it.. third part, king pins were shot.. jacking the front end up and putting a bar in the spindle resulted in movement on a vertical axis.. bad king pin bushings.. replaced and much better.. steering intermediate shaft had apparently never been greased so it had worn and created play in the column prior to entering the steering box.. replaced with new. next part is a bit more lash in the steering box than spec. but not real bad.. bus drives pretty good now and adjusting that box requires quite a bit of disassembly so ive left it for now..



3. Loadstar Superior - Bent rim.. caused excessive shaking in the steering wheel making the bus squirly to drive. steering box very loose.. Bushings in steering box are SHOT.. allowing the worm gear (input) to move in and out with the wheel.. this bus is a full restoration project so its still in process.. steering box will come out next warm day in ohio so it can be rebuilt.. its beyond lash adjustment..



-Christopher

[Johnny Mullet]

Seized or bad king pins will also cause these driveability issues.

[cadillackid]

Originally Posted by Johnny Mullet

Seized or bad king pins will also cause these driveability issues.

it sure did on mine..

[Mountain Gnome]

Originally Posted by o1marc

Member Slummieschap has messaged me with a question:
"I have a 2001 International FE 3900 School bus conversion, 40' Roughly 183,000 miles on a DT466 with a Allison MD3060 - the bus veers to the right and its most troubling when on a straight road and I have to constantly veer it straight. Sometimes its takes a while to get the steering back straight"

Most likely an alignment issue that can be aggravated by worn tires, improper air pressure, etc.
Is there a lot of play in the wheel before the wheels move?
Thoughts from others?

Hey chap:
Are you saying that while driving a strait road it pulls right "for a while" and then you get it back to driving strait and not pulling (and then maybe after a bit it goes back to pulling), or are you saying it is pulling so much you can't get it to "stabilize" ?


My guess is the former is wheel bearings, the latter could be any of the above (including bearings) that Brad_Swiftfur said. He is right on for diagnosis.



My bus pulls just a bit, but after 10K miles, I see no wear on my tires (they look fairly new). The steering wheel is about 10° or so off center while driving strait. Some steering and suspension parts look new, and it seems the steering wheel shaft is mis-aligned by one spline where it feeds into the steering linkage. It makes it so the turn signals are hard to use - one direction they don't want to turn off automatically sometimes, the other, they turn off with just a slight turn off the steering wheel.


Anyone know if I need to pull the whole steering wheel and shaft assembly up and re-align the splines at the linkage, or if I can just pull off the steering wheel from the shaft to re-align the turn-signal shut-off cams?

[Sehnsucht]

Originally Posted by Mountain Gnome

Hey chap:
Are you saying that while driving a strait road it pulls right "for a while" and then you get it back to driving strait and not pulling (and then maybe after a bit it goes back to pulling), or are you saying it is pulling so much you can't get it to "stabilize" ?


My guess is the former is wheel bearings, the latter could be any of the above (including bearings) that Brad_Swiftfur said. He is right on for diagnosis.



My bus pulls just a bit, but after 10K miles, I see no wear on my tires (they look fairly new). The steering wheel is about 10° or so off center while driving strait. Some steering and suspension parts look new, and it seems the steering wheel shaft is mis-aligned by one spline where it feeds into the steering linkage. It makes it so the turn signals are hard to use - one direction they don't want to turn off automatically sometimes, the other, they turn off with just a slight turn off the steering wheel.


Anyone know if I need to pull the whole steering wheel and shaft assembly up and re-align the splines at the linkage, or if I can just pull off the steering wheel from the shaft to re-align the turn-signal shut-off cams?

Obviously I'm responding without having ever seen your setup but usually there is an adjustment knuckle on to drag link which allows you to straighten out the steering wheel relative to what is a straight line driving

[Brad_SwiftFur]

Originally Posted by Mountain Gnome

....The steering wheel is about 10° or so off center while driving strait. Some steering and suspension parts look new, and it seems the steering wheel shaft is mis-aligned by one spline where it feeds into the steering linkage. It makes it so the turn signals are hard to use - one direction they don't want to turn off automatically sometimes, the other, they turn off with just a slight turn off the steering wheel.


Anyone know if I need to pull the whole steering wheel and shaft assembly up and re-align the splines at the linkage, or if I can just pull off the steering wheel from the shaft to re-align the turn-signal shut-off cams?

I'm about 70% sure this is "below" the steering wheel and will need alignment other than simple removal/re-installation of the steering wheel. (If I'm wrong, someone feel free to correct me). I don't know if the turn signal cam has any alignment ability or not.



Either someone has disassembled the shaft and mis-aligned the splines when reassembling it, or the steering linkage(s) were/are way out of adjustment/bent. Since you say the tires aren't showing any abnormal wear, I'll assume the left-to-right tie rod is in good order and reasonably close to proper alignment, but the one from the steering box to the left wheel (I forget the proper name for it) could be faulty.

[slummieschap]

Dear Brad_SwiftFur - apologies for getting back to you so late. Thanks for all your input. I will certainly have all your suggestions put forward. Again thanks for your advice.

[slummieschap]

Mountain Gnome - Great feedback!
Apologies for getting back to you so late. Thanks for your expertise. What a lot of good advice to give my mechanic - In sure hell look at me like i am nuts with all this advice! Again thanks for your advice. slummieschap

[slummieschap]

Thank you banman

[slummieschap]

Thanks sehnsucht. Appreciate it. Happy New Year. slummieschap

[slummieschap]

01marc - got some terrific feedback - thank you again. slummieschap

[o1marc]

Originally Posted by slummieschap

01marc - got some terrific feedback - thank you again. slummieschap

Always willing to help.