Looking for a GREAT alignment shop - Somewhere in ID, WA, OR, WY, MT, ND, SD

[bevans6]

Jim, find the center of your bus, front and rear.  Buy two 2" square .100" wall aluminium tubes that are two feet longer than your bus is wide, mark the center of each tube accurately.  Attach the tubes, probably to the bumper tops or something, so that you have the centers aligned.  Mark four spots on the tubes as close to the sides of the bus as practical, exactly the same distance from center, drill holes carefully, and put in some self-tapping #8 screws, leave them sticking out 1/4".  Drill four more holes inboard of the ones you just did and put in four more #8 screws sticking out same as the first but no need for extreme accuracy as the string will pivot on the accurate screws and be tied off on the inboard screws.  Go to the fishing store and buy some fishing line, two 50 ft rolls or one 100 ft roll (I don't fish, so I have no idea about fishing line), but get the highest test you can, 100 lbs would be good, and tie a loop in one end.  Run the other end around the pivot pin, and slowly tighten the lines equally on both sides, you are trying to avoid cocking the cross-tubes by having unequal tension between the lines.  Now you have your box.

Go to a tool store and buy a high quality steel ruler with graduations down to 1/16" inch.  That is not very fine, but it is a fact that you can easily measure to .015" with such a ruler, by integrating the spaces between the lines.  You can be "dead on", half way between", or "mark-plus" or "mark-minus".  Now me personally I have to get my special reading glasses  that I bought at the drug store to read that, but I need them to read micrometers these days too.  I finally figured out that old guys invented digital readouts...  If you are a machinist like me, you may have a 12" dial calliper that would work better, reading to 1 thou, but it is amazing how accurate you can be with a ruler and string, trust me...  The funny thing is that lasers aren't considered accurate enough for this in the race car world, since the beam is about 1/8" thick, so old trumps new in some things...  Very high end equipment obviously has better accuracy than that.

Now you can start.  rough-center the steering, and then adjust it so you get the same reading difference front to back on each side.   It's difference that you are looking for, since the axle will not be centered accurately unless it's a flluke.  Read to the wheel rim, it's as accurate as you really need.  If you have the fronts 1/16" further in than the rears on each  side, then you have 1/8" of total toe in.  It is important to do this with the steering centered so Ackerman effect is negligible (Ackerman is a designed in condition that the inside wheel in a turn steers more than the outside wheel).

Now go to the back, and make your measurements.  The drive axle should have no toe, to the accuracy that you can measure it.  If it does, it is cocked in the chassis and steering the bus.  If you know trigonometry, or have a handy kid who does, you can calculate the amount of cocking.  At that point you can start to do other things like measure wheelbase and so on.  The tag axles can probably be all over the map as far as toe and such is concerned, and this is a good way  to measure that.  All the time, make sure you aren't measuring dents in wheels.  If brand new race wheels have 10 or 20 thou run-out, and they do, I have no idea what an old 22.5" bus wheel with half a million miles on it will have for run-out.  If you find something that bothers you and you want to eliminate run out, just jack up the wheel and spin it, and find two spots opposite each other that have the same amount of run-out.  Two errors the same equals no error at all...

Camber is the in or outward tilt of the wheels, on my bus it isn't adjustable so I ignore it but you can measure it by determining the level of your ground, the vertical inclination of the wheels and figuring the difference.  It's notated in degrees off 90 degrees to level, negative is in at the top and positive is out at the top, so if your ground slopes down to passenger side by 3 degrees and your passenger side wheel is two degrees off dead vertical tilting out at the top, you have one degree of negative camber.  I use a digital protractor to measure these things as I don't remember my trig and I usually don't have a kid handy...

Castor is the forward or backward tilt of the steering axis, usually a kingpin on our buses.   The lower pivot point leads the upper pivot point so the king pin tilts backwards at the top.  This really helps the bus steer straight, and gives it self-centering action when in corners.  Again it is not easily adjustable on my bus (you could but you'd really have to want to) and it's built in to the axle.  If you really want to measure it there are two ways, one easy, one a little harder.  The easy way is to use your level or your digital protractor to find the level of your ground front to back, then take an eyeball look at the tilt and measure it with your protractor by eye.  You can actually get really close this way if you practice a bit.  I can set castor on a race car by standing over the front hub and looking down at it.  The other way is with turn plates.  Castor affects camber when the wheel is turned so if you turn the wheel exactly 20 degrees from center and measure the camber change and consult a chart or a computer program, it will tell you what the castor is.  What is more important than an actual number is that they are close to being the same side to side so the bus steers straight.  Factory settings on buses sometimes have different castor and camber settings side to side at the front to counteract the steering effect from the camber of the road, at least I assume that is the reason.

Hope this amuses someone, the benefit to me is I had 20 minutes inside in the cool when I should have been outside in the 90 degree heat index sun doing chores...

Brian

[rv_safetyman]

Darn Brian, now there is no need for me to write the article   Great input. 

Clifford, I like the laser idea.  I had not thought about the width being an issue (per Brian).  Probably not a huge issue for our needs (as opposed to race car needs).  I have such a device and will play with it when I set it up.

Brian, the only issue that I want to pick away at is the need to measure the center of the bus.  First of all, it would be really hard to do that (not to sure what would be a good reference - especially for those of us that don't have frames).  Second, I would think that the side of the bus would be a pretty good reference. 

Jim

[bevans6]

If you are sure the side of the bus is accurate and has zero taper, sure.  All you are trying to do is construct a really really accurate rectangle.  Going from center is only the easy way to do that if you happen to know where the center is.  I personally don't think my bus is accurate down the sides to under a 16th of an inch, and to use this technique you need to be able to measure differences in toe to a minimum of 16th of an inch.    But - try this.  Get your tubes on, wrap the strings on and move them around till you have them parallel to the sides of the bus all the way along, to a 16th.  On both sides.  Then measure the distance between the strings front and back.  If the front is the same distance apart as the back, then the sides of the bus are parallel and you have built a rectangle as opposed to a parallelogram or a rhombus or whatever you call it.  If they aren't equal, you have a non-parallel sided shape that you can make into a rectangle by moving both of the strings at one end only in or out by accurately equal amounts (half of the total difference each string, obviously) to match the other end perfectly.  Now - you can proceed as discussed and have at it.  You realize that if you do this and happen to arrange things so the strings are parallel to the sides and happen to also be the same distance from the bus on each side, taking the next step and finding the center of the bus is kind of trivial...

Some people use jack stands to tie the strings to.  I thought of that, and discarded it because ideally you want the strings at center of axle height and that's kind of high for a jack stand.  The other thought was that to get the strings really straight you will need to put around 50 lbs or more of tension on them, and that is going to be hard to control on free-standing stands, but dead easy with the tubes clamped to the bus.  But there is no reason not to be creative.  And since me writing this gives the website the right to use this and publish in any format, there is no reason not to use the ideas in your article.  It's not like I dreamed this up whole one night, this has been around since Archimedes...

Brian

[Busted Knuckle]

Brian (Diehl),
If it were me, and I had your $ I'd have ALL my buses done!
Seriously now, if he will guarantee that it will fix it! I'd have him go ahead and do it! (I'd let him know if it don't fix it, that he can pay Dick Kaiser to fix it right!)

Or on the other hand you could call Dick Kaiser and see what he thinks of it, and maybe just have him do it while your out there!
  BK 

Be safe and enjoy the trip!

[rusty]

Jim, As you know I am doing some major modifications to my 15 and I need to know that ever thing is straight at all times. To set the parallel lines I use four saw horses and weight them down so I can pull the string tight. That way I can set the horses behind and in front of the bus so I can measure to set the parallel lines. It takes a little time to set the strings because you want them to be straight with the bus but it can be done. Castor as Brian says is the angle of the King Pin. I use a digital level to set the king pin. Remember the wheels must be set true centered to do this. When I am all done I will take it to a shop to set it on a machine but with the way I am doing it now I can get it close. Good thread.

Thank You Wayne

[RichardEntrekin]

I have followed this thread with great interest. I became obsessed with the alignment of my rig.

I had two shops in Fort Worth work with it, and both times I was worse off then when I started. Short story is they want to set it up with too little toe in, and one shop tightened the steering gear box, making it impossible to keep in the road.

Long story short, I measured the thrust angle of the rear axle using a modified version of the string method used above. I did establish a centerline of the suspension, and I did pull my perpendicular strings to 10 feet longer on each side of the coach to cut down on measurement error.

I measured my thrust angle that way as 0.06 degrees to the right.

A year later, just for grins when I was at the Newell factory, I had them do an alignment. Cost me 400 bucks for them to tell me the thrust angle was ..................0.06 degrees to the right. It wasn't a total waste of money since they did adjust the tags.
The point is that if you are careful you can get VERY accurate results using string and trigonometry.

[Brian Diehl]

Thanks to everyone being so willing to spend my money I have decided to have RV Frame and Alignment fix my axle alignment problem.  I'm very pleased with the level of service provided so far.  Dick Lorntson stayed late to allow me to get the bus up to him yesterday after the end of my normal day.  He is anticipating needing today and tomorrow to get both axles aligned properly.  I did not here anything from him today.  Given his communication style I've witnessed to date I would say this is a good sign and that he has not run into anything bad in his efforts so far.  I forgot to mention in my last post I was really surprised with the bill to diagnose the alignment problem.  Dick spent an hour and forty minutes going through all 3 axles with me last Thursday looking to find out what was causing my alignment problem.  He walked me through every step of the process and collaborated with me on the diagnostic and parts replacement steps I've already taken trying to narrow down the problem.  No came the surprise ....  the bill was $75.  Remember he spent almost two hours with me.  I was dumb founded.  I asked him about why the bill was so small yesterday when I dropped off the bus and his answer was simple ...  I charged you what I thought the value of what I provided was.  Wow and Wow.  Of course the proof is in the pudding.  I'll update the thread again once I get the bus back with the results of his efforts. 

Here is his web site in case you are interested (his wife runs the website!): http://www.precisionframe.com/

[gumpy]

Brian,

Call me before you go pick up the bus. I might like to meet you there to listen to what he has to say about yours,
and maybe talk to him a bit about mine. If this works out, I may want to take mine in
to have it looked at.

craig