C230K Coupe alignment question

[GuruGuy]

2004 - 4900 miles and left front tire, outside edge of tire was starting to wear....took to dealer. After adjustment, had to go back because of slight "drift" to left and steering wheel was offcenter to the right. After the 2nd alignment, the drift is gone, but the steering wheel still is not perfectly "dead on" as far as being centered. My question concerns the numbers on the print out......at the bottom is a legend that explains the asterick means "out of tolerance" and the d means "exceeds cross tolerance". I have several astericks and several d's...........

Rear Camber
Left is -0 45 * Target is -1 21 +/-0 30

Front Camber
Left is -0 13 d Target is -0 29 +/- 0 22
Right is -0 42 d Target is -0 29 +/- 0 22

Front Caster
Left is 10 42 d Target is 10 32 +/- 0 30
Right is 10 04 d Target is 10 30 +/- 0 30

The guy couldn't really explain it well to me but said it didn't matter and was ok. Something about Cross Tolerance not mattering, etc. This was at RBM of Atlanta Service Express.....

Anyone knowledgable, please provide your input. If you have a book with specs, please see if this is ok....to me it's wrong because it doesn't match the target data.

[Duke2.6]

Cross camber and cross caster (the difference in readings side to side) IS important, and most manufacturers say that is should be no more and 0.5 degree, but my target value is ZERO!

Cross camber and particularly cross caster can cause pull, and any alignment shop should be able to get both within 0.1 of spec with no more than 0.1 difference side to side.

If the wheel is cocked it means the tie rods have to be tweaked - one a hair longer, one a hair shorter to center the wheel and keep the toe setting in spec.

Any qualified alignment guy should understand this. There is WONDERFUL alignment equipment out there, but few techs that are really qualified to operate it who understand the basics of vehicle alignement.

I gave up and started doing my own alignments 20 years ago with an inclinometer and tape measure. I set the front alignment on my 190 to maximum negative camber (about -0.75 deg.) and maximum positive caster (about 10.5 deg.), within the available adjustment and equal on both side. (The rear was okay in my book and I left it alone.)

I later got the dealer to rack it up on their alignment machine. (They owed me a favor.) The tech said he could not have gotten the cross readings any closer than what I achieved.

I believe your car is still in the "adjustment" period, and I believe your settings are far enough out to qualify for warranty adjustment. Frankly, I'm surprised a new car has such sloppy settings! Make sure you get the sheet showing before and after alignment and insist that the settings be within 0.1 degree of spec with no more than 0.1 cross camber and cross camber. If they balk at this, demand factory documentation stating the specified front and rear cross settings.

Also, tell then that you expect the steering wheel to be straight when tracking down a modern well maintained road that does not have much camber. Most modern interstate highways meet this criteria.

The left front outside shoulder tends to suffer greater wear since we go around more RH corners - like freeway on and off ramps. If you can get them to set the front camber to the maximum negative value, which works out to about -0.5 degree, the car will handle better and not chew up the outside shoulders of the front tires as bad. If you are a "sporty" driver and tend to push it on the corners then you definitely want to go to the negative camber spec limit at the front, if not beyond, like I did.



Duke

[GuruGuy]

Does anyone know what the correct specs should be for this car

2004 C230K Coupe

[GuruGuy]

Bump.......

[Duke2.6]

What you posted as "target" are likely the OE specs. They are usually programmed into the alignment machine and printed on the alignment report.

Duke

[GuruGuy]

Which is what I thought. So in that case, it appears things are "in spec" with the exception of the Rear Left Camber which is
-0.45.....target is -1.21 +/- 0.30 that leaves this well outside that range if Im reading correctly....the range would be -0.91 to
-1.51 Is there an adjustment for the rear?


Also, the cross tolerance is another matter and the dealer keeps saying that is ok. He contacted the trainer at MB in Florida and is awaiting a phone call. He also put me in touch with the Hunter guy and I'm awaiting a call from him.

[md21722]

Here are a few things to consider: Alignment is about geometry. Alignment is used to achieve good tire wear and handling. Ride height changes alignment.

On older MB's rear camber was not "adjustable". It had everything to do with ride height. A car that sat too low because of worn parts would have too much camber. The solution was to replace the warn parts - springs, etc.

On the newer cars and older high end models and wagons there is self levelling. If the self levelling is not working correctly, the ride height will be different, and that will change the alignment. Even the new cars have problems. I have seen new S class cars with front level sensors that needed replacement.

One way to check this is to measure from the center of your wheel (on stock wheels use the center of the star) to the underside of the fender lip. Compare side to side measurements, shouldn't be more than 0.5" difference.

Cross camber does matter. In the front some models like as much as 0.5 degrees or more difference to give the car an "on center" feel.

If you aren't satisified with the tech, you can ask the service manager to have the shop foreman look at the car. Some foreman are very good & can identify problems or offer more information than the tech.

RBM was once a highly regarded dealer, I am not sure if that reputation still holds. If you decide to go to another alignment shop, I would shop for an alignment "guy" - NOT their equpment. Much like tire balancing, its more about attitude than equipment. The best alignment shops I use are custom alignment shops that have old style, non-computerized Hunter Lite-A-Line equipment.

[GuruGuy]

Thanks Brian.

I talked to the shop foreman already. It's been 15+ years since he's done an alignment and didn't have a lot of answers to my questions. He did pose my questions to the alignment guy (2 yrs) and to a trainer in Florida (supposedly). Both said the cross tolerance didn't matter and that the rear had no adjustment on it. My problem is that the printout that I received clearly shows (printed in RED) that things are a) Measurement is out of alignment, or b) Exceeds cross tolerance. Totally unacceptable as far as I'm concerned.

I spoke with the owner of RBM Atlanta today and we have yet another appointment scheduled next Thursday to let someone with more experience (25+ years) do the alignment. Hopefully he can solve this problem.

Rear Camber Left -0 45
Rear Camber Right -1 01


Front Camber Left -0 13
Front Camber Right -0 42

Front Caster Left 10 42
Front Caster Right 10 04

Front Toe (pressed) Left 0 06
Right 0 06
(unpressed total) 0 14

[stevebfl]

None of your measurements address your complaint. Your complaint as I read it was that the steering wheel wasn't straight. That has absolutely nothing to do with any of the measurements indicated.

There is considerable missing in the story of your alignment. The first issue is that there is no one spec for your car. A completely different measurement must be made first and then the machine or a table can convert to reading such as you list. This measurement is made by a device called a Romess (sp?) tool. This tool is a sophisticated electornic inclinamometer. The values it gets from placement on the drive axle in the rear and the control arm in the front gives a reading that relates to ride height. If one has a docking station the numbers are converted to caster and camber numbres directly. if not the numbers must be plotted on a chart of Romess numbers versus caster or camber.

Once you have found that all out you can't do anything with it anyway as the new POSes have no caster or camber adjustments anyway. If the car, unlike yours, doesn't track properly and the numbers explain it, (Your numbers say the car should go straight BTW. the cross camber that would give a left drift is opposed by the cross caster which is working to the right and are within acceptable standards) then one can make small corrections to the measurememts by installing bolt kits at the proper control arm attaching points.

I see no problem with your alignment front or REAR. Its my guess they measured wrong on the Romess number in the rear as I wouldn't want negative 1 plus degrees camber on my rear end.

As I pointed out above the steering wheel centering has nothing to do with any of those numbers and is a carelessness on the part of the alignment tech. Other than triggering your steering angle sensor for driving in a circle while the wheels are giving equal speed readings it won't be corrected with any of those angles.

There is basically nothoing that can be changed within standard aligning proceedures for your car. Bolt kits are not an adjustment they require disassembly and are either this way or that no adjustment. The trick is to make the minimum number of bolt kit mods to achieve even tracking. By your statement you are there so the reading are acceptable with the exception of the rear which I believe has the wrong spec attached because of an improper romess measurement.

[GuruGuy]

But what about the fact that the cross tolerances from left to right for front camber and caster exceed what they should be.......

[md21722]

GuruGuy,

Did you measure the side to side ride height of your car? That is one reason the camber might be off. The only real problem you've described for certain is the crooked wheel which they should fix.

I think you're missing the point about the numbers. If your car rides well, goes straight down the road, doesn't jump crooked when crossing things like railroad tracks, doesn't pull left or right strongly, and wears tires evenly, don't worry about it.

Brian

[stevebfl]

Front Camber
Left is -0 13 d Target is -0 29 +/- 0 22
Right is -0 42 d Target is -0 29 +/- 0 22

Front Caster
Left is 10 42 d Target is 10 32 +/- 0 30
Right is 10 04 d Target is 10 30 +/- 0 30

Front left camber - 13 minutes, spec is -29 minutes with a range from -7 to -51minutes. -13 is in that range so is -42, so they satisfy the basic spec easily, the secondary spec is the difference side to side and 30 minutes is acceptable as you are at 29 also acceptable. But none of this means anything without the Romess numbers. The most important thing is that it tracs properly because none of this matters a hoot if it performs properly. Just as having the numbers perfect is a lousy piece of work if it drifts one way or other.

I hate to tell you this but you need to find someone you trust and leave them alone, my job as a diagnostic alignment tech is to fix cars not due audits. The sum total of what hits the road is an endless management of mostly tire variations. MB used to be the class of the road because guys like me could make them stand on their heads and numbers are our guide but there is no exact answer it changes as the tires change. MBs used to have the widest compensation adjustments in the industry. Now there is no adjustment win the car except toe. It has to be rebuilt to change with the bolt kits added.

You can make those numbers straight and the car would probably do fine but other than a right hand caster bias I like the camber bias. I would place one bolt kit on the right front link to impress your numbers without screwing the drive. Since there is nothing wrong with the current situation as I see with the imperfect image given (no romess numbers), I would be hard pressed to see why they would do such a change under warrantee. As goodwill they will probably do whatever you want, try to be reasonable.

As I see it they need to straighten your steering wheel.

[GuruGuy]

Thank-you Steve and Brian.