wheel alignment advices

[mauro12]

Hello guys. Since my tires are extremely old , i think is the right time to replace it . I will go for the size i have now, which is 195/70/14. My concern is about the alignment that most tire shops are not familiar with such old cars. I've read in the forum some basic data about the correct camber , and toe but im sure modern shops do not have in their systems all the data . Is there a more modern mercedes that have some similar data to compare it ? maybe w108 and 109 have a similar geometry but im not too sure . Is there something that can be adjusted by a modern tire shop rather than the normal front toe ? i'm concerned about the rear camber, which seems to be more positive in the right wheel compared to the left wheel . Is this adjustable ? also the rear toe is adjustable too ?
according to this forum , the front toe should be around 0.33 degrees , front camber 0.17 degrees , rear toe as close to 0 and rear camber between 1 and 2 degrees positive .
Last time i did an alignment i had strange numbers on front camber that was -00.09' left and positive 1.26 right .
rear camber +1.5 left and +2.4 right .
rear toe left +1.2
rear toe right +0.6
thurst angle +00.03'

what is your total assesment on those numbers ? thank you very much

[Duncan200]

Mauro,

This is my field of expertise and I train both distributors and end users on these machines almost daily.

A good wheel alignment machine operator does not need the specifications within the machine to be able to perform the alignment. These types of operators are what I call red and green boys.

In regards to your current values, I’d be questioning the levelness of the hoist that the car was aligned on. It’s like all your camber values are leaning to the right.

I can get the specs for you out of the Haynes manual, but from memory it should be Caster 3°30’ (4°30’) +/- 30°, Camber 0° +/- 30’ and Toe in of 0mm to 3mm.

The rear is not adjustable per se, you can change the camber by raising or lowering the ride height. Rear toe is fixed, all you can adjust is the centring of the rear axle via the thrust rod.

All 3 angles on the front are adjustable and like I said a competent wheel alignment specialist would be able to do it properly if you gave him the specifications. Sadly we are a dying breed as no one knows how to do the old stuff anymore. I’m fortunate enough to have a 4 post hoist and wheel alignment machine at home to be able to check mine.

I’ll post the specs out of the manual later for you.

Doug.

[Pawel66]

Perhaps my 2 cents. Since I am no expert here, why don't I write something...

I have noticed that a good alignment guy will have no issue with camber and toe (typical for many cars), they may have an issue with the caster and moving the subframe around. At least they did not know it in my case, I had a manual with me and told them step by step what to loosen and how to move the subframe.

[mauro12]

Duncan

Thank you for your help . Yes it would be great if you can post here all alignment data . What you mean about my camber ? You see strange values ?
I’m experiencing that my car is pulling to the right and maybe this is the reason .
Last time i aligned the car , the specialist was able only to set the front toe .
The rear camber I guess is affected also by the weigh of the entire axle ( hard too on or full fuel ).

[zoegrlh]

On the rear, could be the rear axle spring being weak.

[mauro12]

On the rear right ,the camber is too much positive compared to the left . is 2.5 degrees compared to 1.5 . The specs say maximum 2 degrees of camber . it would be great if Duncan can give us extra advices . The best would be to have an entire video about the alignement for our car .

[Duncan200]

Hello Mauro,

Apologies for the delay.

I have attached a picture of the specifications suggested in the Haynes manual for our cars.

On your car the front camber is -0.09° on the left and +1.26° on the right. The spec is 0° 20’ to 0° 30’ positive. Now please note the specs I’m providing are in degrees and minutes, which means the value is out of 60, as in 60 minutes to 1 degree.

Your values have the decimal point so I suspect that they are measured in decimal degrees which takes the 60 minute value and converts them to a value out of 100. So to give you an example 20 minutes of positive camber which is the spec for the front of our cars equates to 20 out of 60, which in decimal degrees would be 33 out of 100.

 I hope I haven’t lost you with this?

Most wheel alignment machines can have their values changed from reading in degrees and minutes to decimal degrees and vice versa. It can get confusing for an operator who works in decimal degrees when they see a degrees and minutes value of 1° 50’ as they see the 50 out of 100, when it’s actually 50 out of 60 so almost 2 degrees. Anyway I digress.

Back to your car. The reason your car is pulling to the right is because you have too much positive camber on the right front wheel (1.26). This is adjustable via an eccentric cam on the top of the kingpin mount. Both the front cambers need to be between +0°20 and +0°30’ (in Decimal Degrees this would be +0.33 to +0.50)

Also the toe in value for the front is much lower than you have stated, it shows it in the manual as +1.0mm to +3.0mm. This value too can be converted to an angular measurement in degrees and minutes or decimal degrees, but that creates the issue of where the metric value was measured because the further out you measure the wheel angle, the metric value will change. To give you and example, our cars have 14 inch wheels, if the toe value of 1.0 to 3.0 mm of toe is measured at the wheel diameter it would roughly equate to 3 to 9 minutes of Toe in. This concept is very hard to explain but essentially angular measurements never change no matter where along the lines of axis you measure them, but metric measurements change depending on whereabouts on the axis you measure them and they will continue to increase the further out you take that measurement.

I hope the above makes sense to you?

So back to your car, the rear camber on the right is quite high and to the naked eye would be quite visible (top of the wheel sitting out further than the bottom when viewed from the front or back of the car looking alongside). What are your ride heights like? Is the right rear sitting higher than the left? I measure this from the guard lip to the centre of the wheel. If there’s a difference then your right ride height will be higher and this needs to be rectified by either replacing the top spring rubber on the right side with a thinner one or looking and the mounting position of the lower spring plate as this also determines ride height. This is will also play a part in the vehicle pulling to the right, but not as much as the front camber.


One thing I haven’t seen you report is front caster. In the spec this is 3°30’ for non power steering cars and 4°00’ for power steering cars with a 15’ tolerance either way. Your car being LHD would be ideally set up with slightly more caster on the right side to compensate for the crown of the road. As in the road always slopes to the right in your case for drainage (for me in Australia it’s the opposite).

Caster is adjustable by loosening the “D” shackle sway bar mounts and turning the front eccentric bolt to either pull the subframe forward or push it back. When this is adjusted the transmission mount bolt, tailshaft centre slip joint nut and cross brace on the subframe all need to loosened so the subframe can be moved.


Caster is the main angle for straight line stability at speed, correct vehicle tracking and what I call Returnability, the way the steering self centres after turning a tight corner.

The 3 angles of Caster, Camber and Toe all need to be checked. Simply adjusting the Toe on our vehicles is not sufficient.

If the main Caster adjustment needs to be fine tuned, there is also a small adjustment inside the eccentric bolt on top of the kingpin that is utilised to adjust Camber. I usually do not need to adjust this as one it is difficult to do so and two you can usually get the Caster angle good by utilising the front sway bar eccentrics.

The reason I questioned both your front and rear cambers being high was I suspect the hoist may not be level as the values may be leaning to right, as in the hoist may be leaning to the right. This may not be the case, but it may be that your car needs to be rectified first. The front camber on your car is easily adjustable, the rear not so much. A good wheel alignment needs a level hoist, both front to rear and left to right.


I know this is a lot to take in, but I hope you understand what I’m trying to explain.

If you need anything else, please don’t hesitate to ask.

Doug

[mauro12]

Hi ! thank you very much for this very detailed informations . i will post here a copy of the alignment done in 2021 in my car and maybe you can understand better .  My report do not show front caster , i dont know why . What is the easiest way to compensate those numbers ? i dont know if a regular tire shop is able or is willing to put hands on those bolts. Do you have some pictures about the procedure to correct the front camber ? I'm not an expert in this field unfortunately . I remebar quite well that the tire shop guy couldn't find in his computer sistem any data about w113. He found the r107 but the geometry is quite different compared to our cars . The rear camber probably is more visible since i drive always with 1/4 of fuel and with no hard top. I have new bilstein shocks , new subframe and engine mounts and new rear axle mount ( inside the trunk ).

[mauro12]

Here my alignment data during the last check ( 2019). I transleated from Italian to English but is easy to understand. Duncan , your assessment would be appreciated.
Thank you .

[Duncan200]

Here is a picture of my right front suspension during my restoration process.

I’ve circled the camber adjustment bolt.

From memory it’s a 14mm on one side and a 17mm on the other. There is also a small lock plate that is held with a 10mm bolt you can see in this picture. Looks like a triangle that one side has teeth to lock in to the side of the bolt. This bolt can be reached from under the car on the alignment hoist and the wheel does not need to be removed. The adjustment can be done live, as in the car can be on the machine and you can adjust the values.

The report you’ve attached is pretty much the same as the numbers you reported previously, only the toe in value is lower than you said.

The camber on the front needs to be rectified before worrying about resetting the toe in.

In regards to Caster, I don’t have a photo of that adjustment point, but if you look under your car at where the sway bar attaches to the body, you will see a flat spring and two bolts. The bolts need to be loosened and the front one is the adjustment. You’ll see the bottom of the front bolt has two flat sides to be able to be turned. This pulls the subframe forward or back depending on which way you turn it. As I said before, various other attachment points under the car need to be loosened to allow the subframe to move.

I have reached out to my colleagues in Italy to see if they know anyone on Sicilia who has our equipment. Whilst they are based in Correggio, they may be able to help with a workshop who uses our equipment. I can’t promise anything, but I have asked for you.

I think you should focus on getting the front sorted out first before we worry about looking at the rear.

Doug

[Duncan200]

Here are the specs from the Factory Manual for a 230SL.

Going off these your rear right camber isn’t too far away from being in spec.

It does state that the curb weight values are only used as a check and the vehicle must be loaded as per the Test Load for Vehicle Measurement Table.

Interesting to note the specs in the Haynes manual are wrong for the rear.

Doug

[Pawel66]

Here is the picture of the main caster adjustment point attached (it says "front" next to the arrow). You turn the eccentric bolts on both sides and the subframe moves. In order for it to move, several items need to be loosened as described by Duncan in his previous post. You get to see the screws on the picture when you remove leaf springs.

Please note that the detailed caster adjustment (just fine-tuning) can be done by screwing in or out the threaded bushings on the upper control arm, on the same bolt that is used for camber adjustment. By turning these bushings, they move back and forth, helping to fine-tune caster adjustment.

One more thing: in order to align the front axis, you should lock the steering system in the middle. The best way to do it is to screw in fine threaded M8 bolt coned on its end into the steering box - no. 8 on the picture is a plug that needs to unscrewed. When you do it and look inside, while turning the steering wheel slowly near its middle position, you will see an indentation in the piston moving back and forth. Center is when this indentation matches with the plug/screw hole - you screw the screw in and you have gearbox locked in the middle. You may spill some steering fluid when yo do it.

Please also note that some shops may not be able to set toe in in mm, they will need degrees or rather minutes. From what I found out while working on my 280SL is that 1mm is 0deg 10'. So if a wheel needs to have 2mm toe in, it needs to have 0deg 20' toe in.

I wrote manual for this in Polish, made the centering screw and went to Mercedes to work hand in hand with a technician to do the alignment. I went through a lot of puzzle as my leaf springs were not of the same length, which took me some time to discover. So if you have issue setting caster, this may be the culprit.

If your sway bar bushings are not in a good shape, this is the moment to replace them, just pick the correct ones, they may have different offset. Check the specs for your car.

[mauro12]

Hi, thank you for your answers . To adjust the camber you have to turn that bolt cw or ccw? Is it something that can be done by a regular tire shop ? Because I have to decrease the camber in the right and increase in the left . I imagine that my bolt is covered by 60 years of grease and junk .

[Pawel66]

For camber adjustment you turn the eccentric bolt and it moves the upper control arm inside or outside of the car - changing camber this way. Left or right depends on the initial eccentric position.

You undo the lock, turn and see how the camber changes.

A view from the top attached.

In my opinion it is a fairly known way of camber adjustment and technicians will understand it.