How much steering input is normal?

Bob & Tracey · February 03, 2009, 11:31:32 AM

We had the same problem with our power assist and were told "that's the way they are" by shops and others. I drove most of last summer wondering when we would finally leave the road. I assumed the shops that had looked at it had checked the play in the steering gear, they had not! I was able to get a full turn out of the adjusting screw before it made contact inside the box. The pitman shaft was going up and down before it would turn. Now it is very enjoyable to drive with very minor input to correct mostly for wind. The down side... I have to fight my wife for the left seat.

Bob

NJT 5573 · February 03, 2009, 02:24:30 PM

Brian,

No Joke about the additive, it comes in a small bottle and I didn't use 1/4 of it and had immediate improvement. Think it was red in color, its been a couple of years or longer, but the steering gear really liked it.

buswarrior · February 03, 2009, 02:49:38 PM

Yup, check the REAR of the coach.

A bad radius rod back there, tag bushing/alignment, and it will steer the coach for you.

plus all the other good stuff mentioned.

Hard to find a good bus alignment guy who knows where to check BOTH ends.

happy coaching!
buswarrior

Airbag · February 03, 2009, 03:26:48 PM

My MC-5A handles about like the 50 or 60 different school buses I've driven and they all take effort and attention to the road. Some where twenty years old and some where new and all about the same. You might find you are chasing it a little. Get a professional bus driver to give it a spin and see what he or she says.

gmpd4104 · February 03, 2009, 04:19:42 PM

alot of steering input is a sign of something wrong, unless you have an air assit type unit or some other not completley engineered system.

there are alot of people in the truck/car world that will tell you that play/input is normal......it generally is not....it is just they are used to driving something that has a problem, and have come to accept it as normal.

I might suspect your Torsilastics maybe ( Dina's have those correct?) As I understand from lurking about in Eagle and Flxible forums they are the casue of alot of problems when not tunned correctly. It also seems that properly setting them is becoming a lost art...even with some newer buses having them.

Check your ride ht against the specs as well as whatever your maint manual gives you for tors. specs.

Oh tire pressure might also be a culprit.

high PSi will give you better MPG but also effcts handling and tire wear...something Obama doesn't tell you

buswarrior · February 04, 2009, 08:05:24 AM

oh yes, I forgot, ride height is something you can check at home for free.

No matter air suspension or Torsilastic, if the suspension is not riding at the correct height, it can affect your trajectory down the road.

Specs should be in the manual, this requires careful measuring, and the coach parked on a big level surface. 1/4 inch differences matter, so you need to create the conditions for precise measurements.

happy coaching!
buswarrior

busshawg · February 04, 2009, 08:25:38 AM

Just a note, if you do adjust the screw on the steering box be carefull you don't over tighten it. The steering can lock up if it is over tightened. Once you adjust it turn the wheels all the way back and forth a couple of times to be sure it feels smooth and works correctly.

Bob & Tracey · February 04, 2009, 09:27:05 AM

Busshawg,

Good point, it took me several tries before I felt I had it right.

Hartley · February 04, 2009, 01:51:56 PM

If your rear tags are air operated, It could be a low pressure problem that can be
corrected by adjusting the tag air pressure. ( downforce 6,000 lbs or higher. )

MC9's are notorius for wandering if the tag air pressure is too low. or sometimes
too high. Mine was until I found the regulator adjuster was loose. It solved a brake problem with tags locking up and solved all drift and wandering for me.

Oh. Well . Just a thought.

Dave....

busshawg · February 04, 2009, 02:09:50 PM

excellent info Dr. Dave, where do I find my regulator adjustment for the tags? and how do I know how much downward pressure I have, simply by scaling them?

Grant

gus · February 04, 2009, 02:38:33 PM

Brian,

I couldn't tell for sure what type of steering you have by reading all the posts.

If it is air or hyd boost it is actually manual steering when driving straight. It is only power when you turn, this is much different than integral power steering.

As I think has been posted, manual steering play is adjusted at the steering box at the axle. Be sure these adjustments are done in very small amounts to avoid binding the steering.

I had the same problem when I first got my 4104 but was able to take out all but about 1" of play at the steering wheel rim. It sure makes a difference on long trips!!

Lin · February 04, 2009, 03:04:14 PM

I was told that there will be 15 degrees of play with power assist. Does that figure sound right? The figure in inches will be different depending on the width of the wheel.

belfert · February 04, 2009, 03:27:14 PM

I couldn't tell you what type of steering I have other than it is power steering. It is a 1995 so the steering system is likely to be as modern as anything. I don't think steering has changed much since 1995.

My tags are air bag instead of torsilastics like the steer and drive axles. They are supposed to run at 43 PSI and that is what the gauge on the regulator reads.

gus · February 04, 2009, 08:14:55 PM

Lin,

I've never measured but my guess is that 15* is well over an inch at the wheel rim. Anything over an inch with power boost will drive you crazy on long straight roads.

It obviously varies with the wheel diameter but, in the 4104, manual and power boost wheel diameters are the same as far as I know. If the power boost fails you don't know it until you try to turn at low speed.

RickB · February 05, 2009, 05:30:39 AM

Brian,

Once spring arrives here in Minnesnowta. I'll come over and you can drive my bus, I had a 4905 with the Ross integral in my last bus and it was shot and if there was any sidewind at all it was a constant back and forth fight.

My MCI drives better than my tow car does. It would be interesting to see you compare the two.

I think with 14k miles under your belt you probably aren't "oversteering" it but who knows?

If I could get a reasonable throttle that I don't have to push through the floor my bus would be a dream drive.

Have you tslked to ABC in Faribault or Jefferson Lines here in the cities about your issues? Seems that the leasing and touring company mechanics would have alot of experience dealing with steering issues.

Hope you find the solution....

Spring is a coming,

Rick

How much steering input is normal?

Airbag