83 300D camber problem
 

First of all, thanks to everyone here for their vast MB knowledge. I've been a lurker here for years, and have always been able to find answers to my many questions by searching... until now. Here's my situation.

My 300D front tires had terrible wear. The outside tread looked almost new, and the inside tread was worn down to the steel belts. Not good. I got new tires and immediately took it to the local Firestone for alignment. As expected, the camber was way out of whack (-1.2 and -1.1, with the range supposed to be -0.3 - 0.2), but Firestone said they can't adjust it. They said I needed to buy a camber kit.

After searching here I suspected that the problem would be with the UCA bushings, but my local mechanic checked them out and said that they're in good shape. Although he thought the idler arm might need replacing.

Any other thoughts? Did the Firestone guy just not know how to adjust this car? What else could be causing this unusual tire wear?

I should also mention that this is a relatively recent issue. The last few sets of tires had mostly normal wear.

Thanks for any help you can provide.

Randy

If you have worn front end components, then adjusting camber will be a waste of time and money. If you are unable to determine if anything is worn yourself, take your car to a trusted indy to tell you what the deal is.

Scott

Thanks Scott.

I did take it to my mechanic. He looked at the front and said the parts didn't look worn (except for the idler arm -- would that cause the wear I described?).

I guess my question is more along the lines of if the camber can be adjusted at all. The Firestone tech seemed to be under the impression that the 300D didn't have a way to adjust the camber, unless you put in a custom camber kit. But that can't be right. Can it?

When mine had the same problem it was the Lower Control Arm Bushings that were shot.
And, as previously stated you cannot get a lasting alignment with worn parts.

I also do not think that you can see enough of the Lower Control Arm Busings to tell if they are no good.

Both the Lower and Upper Control Arm Bushings pivot on the Elasticity of the Rubber.
In the Pic below you see were the Rubber in my Lower Control Arm Bushing has sheared. It is no longer connected to the other part of the Rubber.
And, you cannot see this from the outside as you are looking at the part that faces inside of the Arm (you have 2 bushing one on each end of each arm).

Also there is an Bolt with an Eccentric Plate on it for adjusting the Camber that goes through the Lower Control Arm. However, it does not have much adjustment range.

Here is what the FSM tells you concernint the Camber adjustment down by the Lower Control Arm.
Camber adjustment range of Cam Bolt at nominal center Value, minus 1 degree to posative 0 degrees 45 minutes.

Camber and Caster have an effect on each other when you adjust.

When you adjust Caster at the Ball Pin down by the Guide/Thrust rod.
30 minutes of Caster adjustment changes the Camber 10 minutes. Caster in the +
direction = Camber in the - direction. Caster in the - direction = Camber in the + direction

Camber is adjusted by turning the eccentric bolt that runs through the lower control arm bushing. Short answer to your question is to get all of your front end components tight, then do your alignment.

Scott

Modern Tire Stores
 

I have found current popular brand name tire stores cannot comprehend
any motor vehicle older than maybe 1995, at best. They are heavily
focused on 2000 and newer.

So, 26mm socket and a breaker bar and you got camber adjustment.
You can do it on the ground without even removing the wheels.

Ask me how I know. I been doing this over the last week to get my alignment
set up.

Odd that your adjustment has changed, that makes me suspicious of lower
control arm rubber bushings.

But the overall thing you really need to know is that camber is way easy to
change on MB 300D.

Agreed on all points.

It's almost impossible for the morons to diagnose bad LCA bushings. And, if they do, they probably don't want to change them (lot of work).

You could put a pry bar against your LCA bushings and see if you get a lot of movement to help tell if they are worn. I'm not advocating that everyone run out and see if they can move their LCA bushing around with a pry bar or that its a failsafe diagnosis method; but it is one tool that may help you diagnose shot bushings.

Scott

Thanks everyone for the information. This has been a big help.

I'm going to take a closer look under there and see if I can figure this out. I'm no stranger to DIY projects on this car, but I've studiously avoided anything to do with the front end. I'm sure I'll be back with another round of questions.

Randy

Here's an update on this situation...

My mechanic did more than look at the bushings. He raised the car up and really did try to move things around with a pry bar, and everything seemed tight (with the exception of the idler arm, which he recommended I replace).

Here's a photo I took of what I think is the eccentric bolt. First, can someone verify that this is indeed the correct bolt (for the driver's side). If this is correct, and assuming I understand how these bolts work (which is a big assumption), it looks like there's plenty of adjustment available to fix my negative camber. Is that correct?

Thanks again for the help.

That is the correct bolt.

You are correct..........there is more than enough adjustment to reduce the negative camber.

Thanks Brian. I think I'm on the right track now.

Randy

Camber correction.
 

I've done my fair share of Mercedes alignments and I can see that there is some adjustment left in that cam, however, I can't tell you by looking at it weather it will be enough to get into specs, you also have to consider caster. Did your mechanic raise your car on an alignment rack with the suspension loaded? The bushings may appear ok and not falling apart but you may need the weight on them to tell if they are sagging too much. The oil on that bushing in the picture can also damage and soften the bushing. Sounds like you need to find a better place for an alignment then Firestone. I have fixed some pretty bad screw-ups from places like Firestone and Sears. The alignment guy there obviously didn't know what he was doing, most alignment machines tell how to make adjustments often times with pictures if you can't figure it out.

+1. I didn't have enough camber adjustment on my car to get one side back into specs. I had to readjust my castor to allow me to get the camber back in spec. Remember, castor affects camber, camber affects toe. Also works in reverse if the adjustments are large enough. I also agree that you shouldn't really trust someone like Firestone to adjust it. Mercedes aren't like other cars even when it comes to alignments. You really should take it to a dealer to get it aligned.

Nice first post jimbonaz. I can tell you've done some Mercedes alignments before. :)

Scott