I just had our w123 85 300Td taken to an alignment specialist. They seem honest and well equipped. They said they couldnt do a proper full alignment because the rear alagn,ent was too off and its affecting the front/rest of the car.

They suggested I get new rear shocks and springs. How can I know if I really need these? I thought the rear suspension was OK, Ive replaces the SLS diaphrams and I have no leakage, but I cant tell if Ive just become accustomed to the poor suspension or if its actually not so bad.

The shop gave a nice printout with the results of the alignment, but its all a little foreign to me. What can someone who knows, say about what these results say.

Its all in french but I wrote beside it the translation as close as I could. I just cant figure out what PARA means.

Thanks for any help

Attached Thumbnails

 

I think it is like our words for or to

Boy that's difficult to read...

...even when you make the picture big




At the moment I'd ignore the bottom half of the report.

Just looking at the "main" angles - from the specifications it looks like

1) The first two lines are for castor
2) The next are for camber
3) The next set are for toe in / out


For the rear, the specs look like

4) Camber
5) Toe

From the measurements on the back I would guess that they didn't start the engine and thus raise the level of the rear end => get the SLS to work <= before they started to say "computer says no"

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

I agree with the Englishman in Holland. Camber and toe on the rear both vary with ride height. They need to measure with the SLS working and leveled out.

__________________
Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

Heres a better quality shot of the Alignment writeup.

So how the can I tell if I really need new rear-end shocks and coil springs? Im pretty sure my SLS is working OK, but as I dont have anything to compare it to, I cant say for sure. Im sure it could be better but, before I go out and buy new shocks and springs, I would hope to determine with my own experience without a doubt they should be replaced.

Is there any way to make a test? would it just be that the car sags more than it should?

A mechanic friend of mine put on some spacers in the coil springs a few years ago, just to bring up the height, would that be an indication they are worn?

It has about 350K on it now.

Attached Thumbnails

 

I don't know about the SLS part but have the Rear Trailing Arm Bushings ever been replaced?

__________________
84 300D, 82 Volvo 244Gl Diesel

I don't know about the SLS part but have the Rear Trailing Arm Bushings ever been replaced?
It also seems reasonable that the test should have been done with the SLS in full operation.
The USA version of the CD Service Manual does not have suspension Specs in it. Stretch has the German Manual and maybe can look up how the Vehicle with the SLS is supposed to be tested.
For Language Translation
Google Translate

__________________
84 300D, 82 Volvo 244Gl Diesel

Even though Im pretty fluent in french, when it comes to car parts or technical names, It can be way off what i thought it would be. I did use Google translate for this document.

So the big question is, how would they know if my rear suspension is needing replacement. (i.e. how could I know) they said springs and shocks.

Is there a fairly easy way to measure and test somehow?

I also just rebuilt my steering box, an replaced my centre tie rod, and had this alignment done, but I still seem to have a slight pull to the right if I let the steering wheel go. Can this actually be due to the rear suspension?

I don't know if Mercedes designed it this way....but most vehicles have a slight pull to the right when you let off the steering wheel.....it is a safety precaution....so in case you fall asleep at the wheel....the car will go into the embankment, ditch or what ever is on the right....instead of drifting into on coming traffic...

__________________

That's a fair amount of accumulated milage. I would expect to find issues in the back end like shot bushings. Thats if you do not have any knowledge of proper rear end maintenance over the years.

Simple test is there a change in the steering when you press and suddenly release the fuel pedal? You will need the stats on the rear sitting height as well with the engine running. It is adjustable. I would normally expect the rear end to seem like it is low with the engine not running personally.

You did tell the alignment guys that that vehicle has an sls system on the rear end? They are uncommon enough to not know it even exists. Plus explain it to them if they did not.

I suspect otherwise they aligned the car with the engine not running and the rear end down perhaps and when you started using the car the rear end rose to its controlled height. In effect perhaps changing the front alignment some what as well. Rear ride level is controlled by the sls system and not springs and shocks.

. A simple test is if you and a friend sit on the rear of the wagon. When somebody starts the engine the rear end should rise. Perhaps you are unaware of this feature especially if it is not working. The model you quote 300td is the station wagon designation I think. The sedans are designated 300d and do not have sls. They do have rear springs.

Most alignment shops have no program on their alignment machines for the 123 chassis as they call for a spreader bar. I hope they did not just shaft you overall by using another Mercedes alignment program like the 107 mentioned by the other poster after myself as well..

Do not feel bad though. For me it is a sickening situation of whenever hiring things out I land up having to be present to make sure whatever the job is is done properly. I spent all day today out in the field with a laser transit doing elevations to make sure I can recheck after the excavators get done. When I neglect to stay on top of things at least fifty percent of the time there are issues unfortunately. Becoming a larger and larger component of todays world I guess or it seems so to me.

I see they used 107 specs for the alignment. The 107 has an entirely different front suspension. They should be using 123 specs.



.

__________________
1983 123.133 California
- GreaseCar Veg System

Isnt that interresting. 107 is referring to some alignment profile,? or is it just saying 107 "All Models" meaning 107 chassis, all models, as opposed to a 123 chassis.

Would that be a pretty big mistake on their part?

I assume they used All models within the 107 chassis spec. If they didn't have the spec for a w123, I would guess the closes to it would be a w126 and then a w116.


.

__________________
1983 123.133 California
- GreaseCar Veg System

Im just wondering if I should be giving them a call... Is this a fairly common practice in an alignement shop if they dont have the exact specs?

Would others think this is a pretty far-off use of their existing specs?

Not defined as mistake . Without owning the spreader bar and it linked to the computer. There is no access for them to the 123 alignment instructions on newer alignment machines. The newer machines just refuse to indicate the required alignment profile for 123s without the bar connected to the computer.

Of the seven alignment machines in my area only one older one will put up the 123 program for alignment without the bar. The other six shops do not own the bar either. For a shop to randomly pick another different Mercedes chassis program is just severe usage at best. Although your pull may not be alignment adjustment related. If it was not present before they played around is an issue though.