Got my bus back with rebuilt steering gear today

[belfert]

Constantly making minor steering corrections is called normal driving. If these small corrections are not made you end up in the ditch.

On a straight highway my car if I let go of the wheel the car will go straight for quite a while.  My bus certainly won't do that.  It would end up in the ditch or the other lane in no time.  If I hold the steering wheel in one spot on my car it will keep going in that direction until I move the wheel again.  With the bus I have to make constant steering corrections when going around curves and such.

The whole reason to have the steering gear rebuilt was to try to reduce the amount of steering input required.  The amount of steering input required is certainly less after the rebuild, but the improvement is less than had I hoped for.  I do realize an old bus will never steer like a new car and this might as good as a bus ever gets.

The steering issues aren't going to stop me from taking the bus out as often as I can.  My friends and I have already been across half the USA twice in the bus.

[JohnEd]

Brian,

I answered you right after you posted about your steering u joint but it obviously went into the either.

The u joint should have absolutely no "play" that you can feel.  Splines are going to have some inherent play but any in u joint should be correctable by replacing them.

Try this:  in a large parking lot, at a max speed for that location...25 mph or less, wind up the wheel for a right turn and then let go of the wheel without braking.  The steering should return to straight.  Then try the other direction.  Camber is what brings it back to center.  When these things are aligned the camber gets set.  Problem is that the real camber called for sometimes can't be achieved and might not be enuf anyway.  Mine needed sooooo many shims it looked dangerous to me.  The tech had showed me where there was no adj possible with my current conditions so I was prepared.  The more camber the more steady she will be but to much wears tires a little and might make the steering more difficult.  You need a experienced mech to tell you what you can get away with.  Any toe out will give your symptoms as will too much toe in.  More than one has said that the tag or drives will also do it if they aren't properly set up.  My understanding is that this busy steering condition is never solved by an awful lot of people.

Good luck with this and I am sure interested in the outcome....tanks!

John

[rv_safetyman]

Brian (and others), I have been thinking quite a bit about this thread.

My Eagle would probably not pass a DOT steering wheel movement test.  I have replace the tie rod ends and made sure that the box is not loose.  But I still have a bit more wheel movement than I would like.

The Eagle still handles very well.  Having said that, I agree with others that suggest that the driver process is really very important.

My steering wheel is the original (large) and in a fairly flat orientation (no tilting).  I find that if I have my hands in the "3 and 9" position, I am always making slight steering adjustments ("sawing the wheel").  If I put my hands at the "5 and 7" (or closer to "6"), I am much more comfortable and make a lot less small adjustments. 

At the "3 and 9" position, you really notice the "slop" in the wheel.  I find that the "slop" is not noticeable when your hands are at the bottom of the wheel.  I tried to reason why (terrible engineering mind habit ) and just gave up.  It works for me.

Jim

[RickB]

FWIW I was able to determine (in my own mind) that our last bus had unacceptable steering play by:

Driving our current bus. The difference is beyond night and day. It is a remarkable, undeniable difference. So my first suggestion is drive someone else's bus where the driver is happy with their steering setup and see how your bus differs from theirs.

Secondly, I was never more aware of my last bus's need for input and correction than when I was in a crosswind and we went under an overpass which momentarily blocked the side wind. Although my current bus is affected by the wind, it doesn't try and jump across two lanes when the wind momentarily stops.

White knuckling is no fun. I remember it well.

Brian, I am picking up my bus in the next couple of days, we should go for a ride and maybe that will give you a baseline to determine if you're expectations are realistic. Our current MCI handles at least as well as the last Prevost I toured in which was a 2000 LeMirage so I am fairly confident that I have "acceptable" steering.

Hope it helps... Well, at least you can tell the goose that took out your windshield that you tried to swerve but your bus didn't respond!!!

Rick

[JohnEd]

Really look forward to that report!

I have watched quite a few bus drivers "in action".  The ones that are the most relaxed and least "busy" are the Prevost drivers.  Little see saw of the wheel and the least input going straight down the road.  The rain water crown of any highway "should" cause a drift to the down side.  Even my Lex moves like that although it moves the least.

Belfert,

If you turn the wheel ever so lightly and get movement and the "pitman" shaft is not moving, the play IS in the "REBUILT" steering gear.  Take it back.  I know that you cannot accomplish the steering gear adjustment anywhere but on the bench and out of the vehicle.  Surgical cleanliness is called for if you open it up.  A box wrench is put on the input shaft and there should be absolutely NO PLAY if it isn't worn and IS adjusted properly.  Given the amt of difficulty you are having I would suggest that you take the box back out and go thru the "tests" for play and verify that all the set-up adjustments are properly done.  I solved this exact problem recently doing exactly that.....mis assembled!!!

I don't think you are asking too much.  Honestly, I don't.  Seems we have run the course on our getting the fix.  I solved my "insoluble" problem by taking the thing to EXPERT alignment shops till I bumped into someone that was smart enuf to diagnose the problem.  They can't charge unless they find the problem....right?  Diagnosis charge is one man hour around here.  Even at the House of Lex.

Good luck with this,

John

[NJT 5573]

Brian,

Once the steer tires take a set they will pretty much drive the same until they are worn out and you get another chance, even when you change other things.

Alignment shops look at specs that give tolerances and tolerances are not good enough. My Eagle does fine with 0 toe and that is a real 0. If it didn't I would shoot for 1/16 inch in. I also had huge problems with chasing the steering, but new R280's and precise toe along with some Lucas Power Steering Additive solved it for me.

Rear steer,( likely tag toe), is also a possible culprit as is steer axle ride height, so get the book out and get friendly with your tape measure.

[JohnEd]

Cupping, panic stop "flat spot", out of round and worn into a misalignment were all cured by having the tire "shaved round".  At least on cars and that was back in the day.  Given the cost of these tires I would think that shops would be able to perform this (rounding) procedure in "this day".

A real confusing experience, for me at least, was my introduction to "radial tire pull".  Logic told me that this was a load of crap.  Had the car aligned and had a lot of pull afterwards.  Alignment was done in conjunction with tire purchase.  Checked alignment twice with no corrective adjustment....I watched.  Was told that they should move the tires around on the front and I was really skeptical.  That cured the pull problem and I have been a believer in Black Magic ever since.

Good luck,

John

[RichardEntrekin]

JohnEd has some good points about how finicky the steering gear box is to free play adjustment. Also, it is extremely hard to tell the difference between a box that is slightly loose and slightly tight in terms of how the coach reacts to steering input. As little is 1/16 of a turn in the adjustment screw can make a lot of difference in how the bus steers.

However, taking one off to adjust it is a pain. Adjusting one by trial and error is tricky. Adjusting one by the feel of the adjusting screw is ineffective.

I did something a little different, and this takes two people. I mounted a dial indicator on the pitman arm coming out of the box. I centered the steering wheel and put two pieces of tape about 2 inches apart on the wheel, and jury rigged a fixed point close to the wheel. I used a bent clothes hangar. I had one of my sons move the steering wheel from one tape mark to the other and back. I measured the total movement on the dial indicator while he did that. I intentionally started with the gear box on the loose side. I continued to tighten the adjustment screw, and tightened the lock nut each time, while recording the movement. You will see the movement range on the dial indicator increase as you decrease the slop in the box. Then you will reach a point where tightening the adjustment screw produces no additional movement in the dial indicator. At that point you have all the play out of the box. Back the adjustment screw off one hair, and you are good to go.

I agree that the best way is to take the box out and adjust on the bench, but if you can't do that, this is a second best approach.

Now, I have a question for the experts. If one of your tag wheels is out of alignment, what happens? Let's say that one of the tags was pointed to the left. Does that make the bus pull to the right or the left?

[belfert]

I haven't driven the bus for a while since it is still in the sick bay with a bad heater hose and broken windshield so I haven't been too worried about the steering.

I would hope the steering box is adjusted properly since it was just rebuilt.

[loosenut]

Check your tires.  I just changed from 24 year old XVA's to new cheap tires.  The difference in the ride is night and day.  With the XVA's the bus felt stable and drove bigger.  With the cheapies the bus wanders as one would expect with a short wheel base vehicle and the ride is a lot busier. 

Mike

[NJT 5573]

Richard,

I don't claim to be an expert, but I think if you have a tag wheel steering the rear of the bus into oncomming traffic,(left) that the input to the steering wheel would be to turn the front of the vehicle to the right to keep it in it's lane. If the tag wheel is only pulling you across the road a couple of inches every 200 feet, you would need to do alot of steering to stay in your lane. 2 inches runout in 200 feet is likely less than 1/8 of an inch adjustment, so everything needs to be real straight if you want a nice driving coach.

Same thing for the drivers, alot of our coaches have been in daily service and seen alot of curbs. If the drivers are pushed back on the passenger side from curbing and the tag is out from wear, the steer axle could be perfect and you could still spend your day steering your butt off. As each axle hits the cross marks in a concrete highway, it will unload the tire a little and regrab the surface, really compounding the driver input senario if the axles are not straight.

You can use a ball of string to check the drive axle. Park on the grass and just come from under the coach and around the drive tire, touching each side of it as high as the body will allow, and go foreward 15 feet past the front of your bus. drive a stake into the ground, tie the string to it and cut it off. Go to the other side and do the same thing. You will see right away how true the axle is running under the coach.

To check the toe on your tag, you can get a real good idea by just putting the tape measure under the coach and measuring the distance behind the tires and in front of the tires on that axle as far off the ground as you can get. It takes a helper and you need to pick a tread groove to use, but after a few measurements, you will get a pretty good ball park idea of what needs attention.

I want my rig to be straight while going foreward with the power on. There is no reason to measure after backing or turning, so be sure that its shook out and pointing straight ahead. I measure semi truck drivers while pulling a hill, so the axles are loaded to the power to the ground position. I just use the trailer brakes to kill the engine, get out and get my measurements and go back to he shop to put them straight using measurements I took with the axles in the power to the road mode. With a bus, I would just kill it on a flat stretch and roll to a stop without any brake so the brakes could not interfere with my foreward motion axle setting preference.

Once you know exactly what needs to be moved, either move it yourself, or take it to the shop and tell them exactly what you want, not what the book says is close enough. Like, I want my R drive axle moved foreward 1/4 inch, or I want the toe on my tag set to zero and thats all I need. My local frame shop, Fosters, in Seattle actually likes that kind of work. They do just what you want, don't go any further and just charge me by the hour for what I want, so every time I visit my rig gets a little better.  The alternative is I take the rig to the frame shop, put all the alignment tools on it and they say well, Larry, its all in spec, your within the + here and the - there, so thanks for stopping by with your $200 and have a nice day.

Mike made a good point about tires. Paccar doesn't get any complaints putting R280's on all their new Peterbilt and Kenworth trucks, or they would not use them. They are not cheap, but you sure gotta love them if you sit behind them, (or in front of them on your bus).

I really don't know what is in the Lucas product for worn power steering gears or gears that wander that is so good, but it sure works.

[Blacksheep]

Not an expert but regarding the tag wheel pointing left and causing the bus to pull one way or the other, I would think neither. In setting up the race car which I DID become very good at and known for, I would actually put the LR toe'd IN to help the car corner. Along with that I would set one rear wheel ahead of the other a measurable distance to achieve what is known as "rear steer" and used widely on dirt racing cars and in the last few years has become popular to pavement cars. The difference is which tire is the leading tire! Does this compare to your question? Probably not but the situation is similar with the only difference being our rear wheels on the car are drives where as tags are free rolling!
Again, not an expert just my opinion!

Ace

[NJT 5573]

Ace,

When I set my circle burners up like you say, they drive themselves around the corner and I actually have to steer them down the straight away. My preference too.

[RichardEntrekin]

Thanks NJT.

I have spent a lot of time with string, tape measures, laser pointers, and a home made castor camber gauge to get the very best drive I can. Your explanation made a lot of sense. I really appreciated the insight about how much steering input correction a constant pull to one side would make as the road conditions varied mile after mile.

As for as my question about the tags. I can imagine two different scenarios. The first is if the tag tire is pointed to the left, then it could just move the rear of the bus left as you go down the highway, moving the whole bus left, meaning you would have to input a steering correction to the right. On the other hand, a tag pointing the left could use the drive wheels as a fulcrum so to speak and cause the bus to pull right, needing a correction to the left. I was just curious if anyone had ever found their bogey out of alignment, and what they noticed when it was aligned.

[JackConrad]

Another factor that can have a big effect on handling is worn radius rod bushings. If the rear bushings are worn, they let the rear axle "wiggle". Each "wiggle" requires steering input to correct the "wiggle".  Jack