front end alignment question

[bevans6]

I'm taking my MCI MC-5C in for a front end alignment today.  My issue is that I measure about 1/4" plus toe out, and it wanders on the road, and won't point in to corners very well, you turn in, and it's always too much, and you can't be smooth with it.

the spec from MCI is 1/16" toe in, plus or minus a 16th.  they describe chalking the tire and measuring with trammel  bars, and i assume they mean to measure at the tread, half way up the tire.  Is that correct?

Given that I am not particularly interested in maximum tire wear, and am completely interested in it not wandering on the road, I want it to steer straight as it can, what toe setting should I ask for?  I was thinking high side of stock, or 1/8" total.

Thanks, Brian

[luvrbus]

Brian, a toe end setting is not going to correct your wandering that is a caster or worn parts problem also if the steering has been changed the steering box could be off center  


good luck

[Ednj]

 Take it to a shop that aligns buses so they can check front and rear alignment, it might be dog walking.
I would think a toe in would keep it going straight not toe out.

[bevans6]

Hi.  the bus front end was rebuilt about 30,000 miles ago, with a lot of new parts including king pins, drag link, tie rod and tie rod ends.  It was checked about 500 miles ago when I bought it, as part of the safety check.  I happen to know that both shops that worked on it don't have alignment  bays, so...  Hopefully  today they will check all that again, but I put new shocks on a couple of weeks ago, and the radius arm bushings all look perfect.  I can't check castor (but the alignment shop can), and as you suggest it may be out - but I don't think it can be adjusted either, can it?  And the stock castor settings are very low anyway, only 1.5 degrees.

so we will see what we see, and if it doesn't help the wandering, then it crosses a couple of things off the list, which is always good.  Do you have a suggestion for the toe setting anyway?

brian

[luvrbus]

Sure you can adjust the castor on a axle they bend the axle I watched Dick Kaiser in Eugene do Prevost and MCI for years he always uses 3 degrees to stop the wandering 


good luck

[bevans6]

Do they do it on the bus or off?  Heat and a big wrench?  3 degrees seems more like it to me, too, I'll ask about that when i am there this afternoon. 

thanks, Brian

[JohnEd]

Wait!  Lets talk a minute.  I had the exact same problem a couple weeks ago.  It wandered badly and it seemed to lunge into a corner and need constant correction to stay on the road.  Really bad and all I could do to maintain.  Wife drive it...out of the question.

I took it to Dick Kaiser in Eugene.  Great guy and smart and fair about the pricing.  He determined that my rear shackles were loose a tad and over the years the inner tube was all wallowed out.  While he had the springs out he re curved them and added a leaf.  My steering problems were slightly improved....I think.  I know I needed everything he did but that wasn't the major cause but must have contributed.  My front shackles must also be wallowed out like the rear.  I figured I could pull the fronts and take them in.  I didn't want to get it aligned as the front work and even the rear work will affect the alignment.  With nothing to loose I turned in an additional 1/16 on the front.  It was sitting at zero.  I noticed that the coach would seem to track fine at under 25 MPH and get worse the faster I went.  That sixteenth of a friggen inch resolved ALL my steering problems.  Tracks perfectly and hugs the corners so well I am driving way to fast to get any wear out of the new steer tires.  Happy camper I be.  You can always put the adjustment back where it was so there is no risk.  Try it.  I think my MPG will go up with this move.

Caster is in there to cause the thing to return to center and that will keep it going straight.  Let there be no doubt that no caster will give you wandering steering.  Let me add, toe out will "overcome" all the caster you can put in there and cause severe wandering.  Gotta have both and caster adjust will affect toe but toe adjust won't affect caster.

Good luck,

John

[TomC]

Relatively easy way to tell if you have enough caster is does the steering wheel return on itself from a turn?  Also, 1/16" toe in should be the maximum toe in-radials are very sensitive.  Going from toe out to toe in, you'll feel a big difference.  Good Luck, TomC

[bevans6]

Well, just back from the shop and the results of the Hunter 4 wheel alignment are that my bus is within all specs and they wouldn't change a thing!  Toe turned out to be .02" which I believe means minutes of angle, toe in, within a spec of .00" to .06", so maybe on the low side but definitely within spec.  The rear was fine as well.  Castor was 2.6 deg. left, 2.8 deg right.  Hardest part was finding the place, I forgot how to get there, and then getting it in straight over the pit - long wheel base, tight turn into the bay = three or four tries.

So knowing that everything was right, the bus handled a lot better coming home than going   

Not really, but knowing that it's right means that I can relax and enjoy driving it more.  The new door seals make a ton of difference to wind noise, and the heater works, so I would appear to be good to go!

cheers, Brian

[JohnEd]

Tom,

I agree that caster is evaluated by how well she returns to straight.  With my no toe condition she returned to almost center and that varied from right to left.  I know that as speed increases the resistance of a tire to rolling increases.  That resistance gets translated to pressure on the front axle that tends to push the tire into a toe out alignment.  The older the the steering components and the accrued slop, the more toe in you need to compensate for the inherent toe out that develops.  My experience of late tracks this "old wisdom" perfectly.  I know that radials are supposed to have virtually no rolling resistance but I also know that in reality they only have less.  Truck tires are radial in name only, I think.  One aspect of a radial tires design is that there is a lot of flex in the sidewall and none of my tires had that flex but instead had very robust and stiff sidewalls.  The resistance of the sidewall to flex is what contributes to rolling resistance.  That and "squirm" that the radial plies resolve.

I still say that if you have wander you should "try" readjusting your toe and evaluate the effects that has on your problem.  Easy to put back.  1/2 turn equals 1/16 toe on my front end.

Thanks for your comments,

John

[Fred Mc]

Toe is very easy to do at home.

Jack up both front wheels so they turn freely. Put a chalk mark on the tread of the tire. Measure the distance when the chalk marks point to the front. Then rotate the tires and measure when the chalk marks point toward the rear. You can use a string or make a "trammel" bar . You could probably do it with the tires still on the ground but its a little more difficult. Probably the hardest part will be rotating the tie rod if it hasn't been adjusted in years(decades?)

Fred.

[Busted Knuckle]

Brian I would have a good SPRING & FRAME shop check the specs on the front axle itself! Not MCI's specs!
I once had a brand new Freightliner that wore the front tire unevenly, drove like crap & pulled to the left. I took it in numerous times to be aligned at the dealer I bought it from & and several others too!
They all said the same thing! NOTHING OUT OF SPECS!
Then one day a an old hand recommended Fort Smith Spring & Frame and told me if they couldn't fix it nobody could!
I called and the shop manager assured me they could & would fix it! So I took it in for them to look at!
After only 10 minutes they told me yes it was indeed the front axle was out of tolerances for the axle mfg specs and that Freightliner "purposely had loose specs so could pass!"
Well I asked him what the cure was and he said "we're already working on it and will be done in an hr!"
Then he told me they set up a "press" and bend the axle into specs! An hr later I was on the road again and it drove like a dream! Never had a problem after that!
Worth having it checked. Like Clifford said it isn't hard to do with the right equipment and correct specs!
FWIW
 BK  

[bevans6]

Actually it is a spring and frame shop, around the only one in Hamilton with a computer alignment bay that does most of the dealer work, I found out.  The Hunter computer had the axle specs as well as the specs for MCI, they were about the same.  We compared a 102D3, an MC8 and the axle, and they were all the same.  I think I will just drive it for a while.  I am pretty sure my tires are a bit over-inflated, but I will leave them a bit high until I can get it weighed properly.  they are no more than 10 psi high.  I am going to grease the front end too, the PO was supposed to have had it done, but it doesn't look like it.  everything is tight that's supposed to be tight and loose that's supposed to be loose, and that is good to have double checked by someone who knows as well.

Brian

[TomC]

Caster is adjusted with wedge shims.  Camber is where you have to bend the axle if the tires are not 90 degrees to the road.  And as to toe- run 1/32 to 1/16" toe in-never toe out.  Toe out makes it squirrelly.  Good Luck, TomC

[edroelle]

Toe out can produce slight wander.  That is why the spec call for 0 to toe in.

Do you have integral steering?

Ed Roelle
Flint, MI