Any wheel alignment expert here? - PeachParts Mercedes-Benz Forum

funola · #1 01-05-2015, 02:58 PM

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.

BillGrissom · #2 01-05-2015, 03:25 PM

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".

ah-kay · #3 01-05-2015, 04:39 PM

Check post #13 here

rscurtis · #4 01-05-2015, 04:55 PM

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

pmckechnie · #5 01-05-2015, 06:53 PM

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

KarTek · #6 01-05-2015, 07:05 PM

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

leathermang · #7 01-05-2015, 07:18 PM

Quote:

Originally Posted by pmckechnie

.... 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

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...

ah-kay · #8 01-05-2015, 07:32 PM

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

97 SL320 · #9 01-05-2015, 08:18 PM

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.

leathermang · #10 01-05-2015, 08:48 PM

Quote:

Originally Posted by ah-kay

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

$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...

ah-kay · #11 01-05-2015, 08:57 PM

Quote:

Originally Posted by leathermang

$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.

leathermang · #12 01-05-2015, 09:05 PM

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....

funola · #13 03-23-2015, 12:13 AM

Quote:

Originally Posted by BillGrissom

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".

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.

Junkman · #14 03-23-2015, 10:55 AM

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..

jbach36 · #15 03-23-2015, 01:13 PM

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.