Any wheel alignment expert here?
 

I have a car (not Mercedes) that just had outer tie rods replaced. I got the toe in close to spec but the steering wheel is not centered. I do not want to pull the steering wheel to center it since the turn signal cancel will not work right then.

I know I need to adjust the tie rod lengths equally on both sides to center the steering wheel. My steering wheel is currently turned to the right about 30 degrees currently while the car is going straight on the highway. To center the steering wheel, my question is:

Do I shorten the driver's side tie rod and lengthen the passenger's tie rod equally, or is it the other way around?

I am directing this question to those who have worked in an alignment shop before. I have come across this problem before and what I thought was right turns out to be the opposite. I am trying to save time if you know what I mean.

I haven't worked in a shop, but have done so myself, plus have several mechanical engineering degrees so at least try to figure things out. You couldn't re-clock the steering wheel anyway, since it surely has a locating groove (most cars, as does Pitman arm).

Since your steering wheel is pointing 30 deg right w/ tires straight ahead, if you were to make your steering wheel straight, the tires would then point left. Thus, increase the left tie rod and decrease right tie rod (same amount) to make the wheels point straight in that condition (brilliant reasoning, or what?). You can get real close if you hold a straight edge along each tire and sight at the rear wheels, and make them equal (w/ steering straight). Best to have full weight on front end, and the tires free to rotate (2 smooth plastic floor tiles stacked works).

BTW, if your front end parts are new and tight, shoot for 1/16" toe-in, or 1/8" if worn w/ play. The idea is that the tires will be perfectly parallel while driving. Measure as high up on the tires as you can without bumping into parts, but same height across fwd & aft sides of front tires. If tires have straight channels, it is easier. I find w/ a tape measure, <1/8 turn of an adjuster is quite noticeable, so doubt a high priced laser machine can do much better, but I am sure many ranters here with no experience will state "don't do it".

Check post #13 here

Also, by moving the steering wheel, you'll be out of the center of the steering box for straight-ahead driving.

I am not the smartest on this site, but unless I missed something, the OP said "I have a car (not Mercedes)......". I can't answer his question because some cars (not Mercedes) have the tie rods in front of the wheels and some have them behind the wheels. I can't come up with a way to say which way to turn the tie rods not having all the facts.

PaulM

If the car is "front steer", shorten the drivers side and lengthen the passenger side. If it's "rear steer" do the opposite.

I am pretty sure.... that the relative position of the tie rod connection to the tires also affects which side of the tires you would be measuring the ' toe in'..
meaning that some cars would wind up being set with ' toe out' if measured at the front of the tire....
The OP really needs to get a FSM for the car in question... and follow it...

I also think there is something basically wrong if the wheel if that far off..
THE result might be that you would not have the same amount of turn available in both directions.... that is dangerous... because it will come as a surprise...
MWards did that to a riding mower one time.. and my sister ran over over a small tree when she could not turn the mower the direction she needed to... it was a specimen tree.... and she knew it.... the look on her face was priceless...

Please don't make a mountain out of a mole hill. Alignment is not rocket science. You don't need FSM. You only need a tape measure, spanners and the specification.

My $0.02

Think of this as having the tires locked into place then trying to turn steering wheel to the left.

If tie rods are in front of wheel center line, left needs to be shorter and right longer by equal amounts.

If tie rods are behind wheel center line, the left needs to be longer and right shorter by equal amounts.

I'd go 1 turn in adjustment, recheck toe then drive and note result. ( even if toe is slightly off, it will be OK to drive to check steering center. ) If too far / not enough, you can now judge how far to make next adjustment.

When correcting steering center and toe at the same time, I treat each adjustment by it's self noting longer / shorter and by an estimated amount. Then, if the right needs to be longer to center the wheel, and right needs to be shorter to correct toe, no change is made. This means that the left needs to be changed by an additive amount from the center / toe change.

$0.02 is exactly what that is worth. It is not rocket science.. but it IS physics... and I have worked in a front end shop... replacing the tie rods should not cause the wheel to be 30 degrees off.... something basic is wrong... and steering and brakes have to be right...

FWIW - Steering cock-eye-ed by 30 degree is nothing. It happens all the time. It only takes 1/4 turn on the tie-rod sto fix that, BTDT. I have never worked in a 'front end shop'. I work in the high tech shop, but to me, alignment and brake is a piece of cake.

If he checks the FSM he may find the steering box can be locked centered.... like the MB...
It may be easier to pull a string across the rear tires and measure in from them to get basic center... with the steering wheel tied straight....

Yes, brilliant reasoning! Finally used it today to straighten out the steering wheel on my VW. I set the toe-in to zero just to try it- tracks straight, not twitchy nor does it wander. I'll try 1/16" toe-in next and see if I feel any difference. Did not use any slip plates or spreader bars, I just roll the car forward so the wheels make a few revolutions (in a parking lot) after marking the rear of the front tires. I am able to make repeatable measurements so I trust the tool I am using. Making the measurement is easy, knowing which direction to make the adjustments and by how much was the hard part. It took quite a few iterations before I got the wheel centered and the toe-in set to what I want.

Question for you BillGrissom: If the wheels are pointing straight but the steering wheel is not perfectly centered but turned 1 degree to the the right, and the wheels are slightly toe-ed out, which single tie rod do you adjust to bring toe out back in and straighten the steering wheel at the same time? Do you lengthen or shorten that tie rod? I have trouble visualizing this and could use some more brilliant reasoning. I am considering making a mock up of the steering system with a steering wheel, rack and pinion, adjustable tie rods and wheels so that I don't have to think and get confused in future alignments.

The Dodge ram has an adjustment where you can adjust only the steering wheel. You want to make sure that the steering box is near the center of its range of motion or you'll be able to turn tight in one direction only. Adjust toe to match steering box. Adjust steering wheel to match box. Of course you shouldn't need much adjustment unless someone has screwed it up and once set not much should be needed in the future..

I got the lifetime alignment at Firestone for $150.
 

Glad I paid more over a one-time alignment (which cost about $100 at other places) to get the lifetime alignment. Now I pop in maybe once every 6 months or so, and don't have to pay anymore.

You'll never get them within the 1mm you need to be to keep your tires from wearing out. Just get an alignment.

Funny you mention Firestone's lifetime alignment. That's what I paid for on this VW and man was I sorry I did. Last summer, I wanted to do a bunch of front end work in stages and thought it would pay off to get a lifetime alignment. Not only did the they not do the camber adjustment which was what I really needed since I could only do toe-in with the tools I have, the Firestone idiot used an oxy-acetylene torch to heat the tie rod end nuts red hot to get them loose when he could have just used penetrating oil since those were TRW tie rod ends that I put on less than 2 years ago so they should not have been rusted in place and easy to undo. Anyway I ended with 2 melted tie rod end boots and heat blistered outer CV boot which spewed all the grease out. I went back to Firestone with pictures of the damage and threatened to post a bad online review and after a lot of haggling, they refunded my money. So this Firestone lifetime alignment ended up costing me 2 tie rod ends, 2 new CV joints and the labor to install.

Is this your experience DIY? I have been doing my own toe-in for a long time and can get it better than 1 mm.

I only let dealerships do my alignments. If they break something then they would fix it. Not like they would ever do something this stupid.

Really? How are you measuring that?
Most toe specs call for something like .24 degrees total toe.
That's about 1mm at the front of the tires vs measured at the back of the tires.
You must have the largest vernier caliper on earth!

1 mm = 1/32", which can be resolved on a tape measure, but hard to imagine it really matters. My 1960's Chrysler cars spec 1/16 to 1/8" toe-in, and I doubt their tires are fussier than "Mercedes tires". Shoot for the former if all parts are new and tight. After a few years wear, and as the ride height changes (more important), toe-in will change quite a bit, so lucky if within 1/16" "as found" at the next adjustment interval. More important is to measure and adjust regularly (~3 yrs), than fuss over 1 mm.

What is the error in the tape measure you're using? What is the error in your ability to read that tape measure? I guarantee the error is at least +/- 2mm. The width of the line on the measuring tape is not zero width! Also how accurate is the tape? The ability to line up one end would be +/- 1mm, but you are doing it twice, at each end, so the error in measuring is at least +/- 2mm. Now, how good are your eyes or your ability to reduce parallax error in your measurment? Probably 1mm again, so another 2mm, So realistically your measurment is probably no better than +/- 4mm. If you don't understand why then pick up any book on error analysis.

1/16" is 1.59mm which is nearly the same as my 300SD, with 14 inch wheels the 0.24 degrees toe would be 1.3mm at the tire tread. You might fool yourself into thinking you can measure this accurately with a tape, but you're wrong.

That's exacly what I have.

[QUOTE=rob300SD;3456461 ... So realistically your measurment is probably no better than +/- 4mm. If you don't understand why then pick up any book on error analysis. ...[/QUOTE]

I am an engineer and know error analysis, plus I work with Metrology. 4 mm = 3/16". That would be pretty far off even for house carpentry, and people use tape measures there. No parallax error since the tape measure is right against the tire. After setting toe-in, I have repeated the measurement and get the same difference within 1/16". After driving around the block and jouncing the suspension, I have noted a 3/32" change, so I doubt you would hold any dimension tighter than that for long no matter how you measure. I am hardly the first person to use a tape measure to measure toe-in (search internet).

Rubber tires have some flex to accomodate slight mis-alignment anyway. As I mentioned, toe-in changes with body height. If you don't believe me, have a helper sit on the hood and see how much your toe-in changes. The suspension does sag over time, thus toe-in changes.

I don't think you can do a very good job with a tape measure without a helper. Even then , you can't measure at the center line of the tire (most accurate spot to measure) because the unibody is in the way when measuring the rear of the tires.

Just checked the toe-in on my 85 300D and it is fine. My caliper has thumbtacks on both ends.

First apply masking tape to the tires then pin the caliper into the rubber.
http://i31.photobucket.com/albums/c3...324_164301.jpg

Remove caliper and circle the pin marks so you can see them easily later.
This one is the driver's tire
http://i31.photobucket.com/albums/c3...324_164354.jpg

This one is passenger tire
http://i31.photobucket.com/albums/c3...324_164432.jpg


Roll the car tires forward 180 degrees then stick the thumbtack in driver's tire's circled pin hole, then stick other thumbtack into the tire of the passenger tire.
http://i31.photobucket.com/albums/c3...324_164920.jpg

This is where the passeger tire thumbtack landed, a tiny bit out from the first pin hole = toe-in. If it was further out, then it would be toe-out.
http://i31.photobucket.com/albums/c3...324_165138.jpg

Vernier caliper says toe-in is 2 mm. I am going to make an improvement by glueing a tape measure strip with 1/32" increments to the caliper so I can read right off of it so I don't have to use the vernier.
http://i31.photobucket.com/albums/c3...324_165330.jpg

Ah, that is much better than I had imagined. I'd say this was a decent method. So long as the tacks don't bend and the rig doesn't flex at all.

It is light (all aluminum), does not bend or flex, confirmed by repeatable measurements. I've been using this method successfully for a long time. Takes under 5 minutes to get an accurate toe reading.

I have seen similar caliper devices sold for do-it-yourselfers. I think you normally rest them on the ground and the arms are adjustable so you can set them to align exactly with a feature on the tire (ex. groove edge). With a tape measure, I must measure about 2" lower than you can with the caliper, but I do go the same height up on both sides.

Most recommend marking a spot on the tire, as you do, then rolling the car so that spot moves to the other side. However, if you spin the wheel and the channels move around <1/16", they are fine as a location guide and no real need to use same point on the tire. I never bother rolling the car forward. If I do roll it and measure at a different location on the grooves, I get the same toe-in.

You can do it by yourself if you duct tape the tape measure end, but easier to get my wife to hold it. She is trained now, so we can check a car in <5 min. An even quicker test is to hold a straight-edge against each front tire and sight at the rear wheels. The line should hit ~1" off the rear tire, if RWD. Of course, someone needs to hold a ruler or such to judge that "point in the air". It is even easier for FWD since you want to see ~1" in on the rear tire, which is the 1st groove on most. You want slight toe-out for a FWD car. Why? For both, you want the front tires exactly parallel when driving. When FWD front tires pull, they tend to rotate slightly (from play in steering/suspension) towards toe-in. Best to always err on the side of a little toe-in since any toe-out (while driving) makes the vehicle wander.

Firestone has been great for me
 

Pretty outrageous that some rogue Firestone employee would be using a torch to fix some stuff on your car to do an alignment. I highly doubt that's their norm. With me, I tell them to do the alignment and no other 'safety inspections' where they look to make extra money off of you. They've done a great job on alignments (maybe not perfect according to MB purists) many times, at no additional costs. I've probably gotten 9 alignments so far for the one time payment of $150.

I was charged a $10 shop supply fee on top of the $170 lifetime alignment fee, I suppose that was for the oxy-acetylene? The manager I dealt with defended it's use, saying they use it all the time.

I've been driving the Jetta with zero toe-in and it drove great. On the flat, if I let go of the steering wheel, it stays straight. I have since adjusted the toe-in to 1/8" and there is not a lot of difference other than a little more steering effort and the steering wheel wants to return to center more. Either setting is fine with me. What I care most is no uneven tire wear so I will aim for that.