Super! Now if I was currently in a country that didn't ban utube, I could watch those.

FWIW, I've been playing around with getting the toe-in adjustment on my w124 just right (or so I think), and learned a lot in the process. Sharing some maybe common knowledge here about it.

I used the string method to measure toe-in. Pull a string at hub height along side of the car, set string an equal distance (couple inches) away from center of each hub. Then use calipers to probe distance between the string and wheel rim, at the leading edge then again at trailing edge of the wheel. Difference divided by 2 is your toe measurement - for that wheel.

My goal was to have zero toe on the front tires. First, I tried doing this by parking front wheels on greased tile sandwiches and proceeded to set both tires to zero. Test drive revealed dancing around on the road a little too much for my liking.

Get back, and did not park on greased tiles this time I measure toe again. They're toed out! Each about 0.080". Aha! This probably has something to do with the "spreader bar" that I don't have and road force and w124 geometry, etc.. When you park on greased tiles the wheels must ease together (toe-in) a bit by themselves, with the lack of "road force". Versus if you roll to a stop on solid ground your front wheels are going to be splayed out a bit. I presume when you're driving on the highway they keep a splayed out stance so my first "zero toe" attempt was in fact toe-out at speed, and it felt like it. Skittish.

OK. So I don't own a spreader bar. I parked on greased tiles again, and dialed in an equal amount of toe-in on the front tires. I set each wheel to toe-in about 0.080". Went for a drive, this was much better! Less dance on the highway, steering wheel was a little off center (my fault for not parking it exactly straight when I did the adjustment)... but this time held a line on the road much better. Less susceptible to cross winds too.

I have yet to go down and check what the "standing toe" is now that the car is parked on solid ground after test run.

Through this whole process and test drives, I learned the car drives better with perhaps a little too much toe-in rather than not enough (neutral or even a little toe out).

I used a 22mm crowsfoot socket on the end of a socket extension to reach in at the adjuster nut on the tie-rod. Some people use vise grips - PO did on the previous tie-rod you could tell with the marks.

Can anybody with a w124 and perfectly done fresh alignment please use the string method to report what the "natural" amount of "standing toe" is for this car is parked on cement?

What I'm trying to arrive at is what is the "correct amount" of toe-in adjustment needed when NOT using a spreader bar.

Although my car is driving much better now, maybe those wheels are still splaying out at speed more than they should be and I might need to dial in more toe.

As long as you are not using bias ply tires, the correct amount of toe is ZERO! If you have drivability issues with true zero toe then there is something else wrong.

I have driven a combination of MB 123 and 124 cars well over a million miles. During this time I only had professional alignment ONCE. I have personally set toe on these cars at LEAST two dozen different times and probably many more than that.

The important prerequisites for toe setting are properly adjusted wheel bearings and the wheels must have rolled at least one full turn on flat floor before the check. If your greased tiles are adequately frictionless, then this PROBABLY does away with the need for the roll.

Are you sure that your wheel bearings are tight?

Well.. I always drive onto the greased tiles, so there's the tire rotations there. And they are frictionless enough that when I'm turning one nut on the tie rod with a hand tool I can watch the wheel toe in or out with the direction I turn.

I just did all front wheel bearings (according to the book using dial gauge for end play). There is no discernible wobble or hand-detectable free play in bearings, wheels free spin a few rotations in the air, so they're not binding too tight either.

I recently got all new tie rods and a professional wheel alignment. After this it had an ever so slight pull to the right and steering wheel off center in that direction too, tech said "maybe a radial pull". (Later I swapped tires left to right and no change..). I remember they were adjusting caster on one wheel, spent a lot of time on that. Basically got it near spec then ran out of caster adjustment room.

Then I went and put in the new center drag link and steering dampner, and is why I started playing with the toe.. This part replacement immediately increased my pull and off center. But I'm at the point where I am very close to driving nearly perfectly straight and I can take my hands off the wheel at highway speed and car goes continues straight (stays in lane) hundreds of yards. So.... I'm pretty close.

Struts could be the originals on this car, lower bushings are showing their age but two different techs say "not too bad", strut top rubber mounts are showing a little cracking but look whole. Car sits even at correct ride height.

Not sure of condition of steering idler arm on passenger side, maybe it's offering a little slack in the system?

What concerns me regarding the above post is that you said that it pulled AFTER having a professional alignment. Unfortunately, it is all too common for alignment jobs are actually "set the toe and let it go." You need to verify all settings and components. The toe settings should not be having the effects that you describe.

Pull is strong word... when they were done slight drift was more like it. You could write it off as "crown in the road" causing it.. or radial pull. Yes, they took it for a few test drives during the process. Had it on the alignment rack for a couple hours, lots of computer and manual measurements being done, they handle a lot of Mercedes and was why I was referred to them. I watched them and chatted throughout the process and he was cool with that... I don't think any sloppy workmanship happened. These guys would consult with each other in the pits to come and have a look, or what do you think, and double check each other's work. Seasoned guys, not kids.

Larry, you've done so many alignments. I've got the string set up for toe. I'm very meticulous with measurements, hand repeatable using a caliper to within a few thousands. I'm parked on greased tiles to adjust toe, it's very slippery and doable. The tiles are each about 1/8" thick hard linoleum, if that's a concern?

1. What is the correct toe to dial in to a 1987 w124 after rolling the car up onto this setup? Zero or slight toe in? (Remember I don't have a spreader bar).

2. Does slack or wear in the idler arm contribute to play in toe? Or any of the other components that have not been recently replaced on this car?

With radial tires I set toe on ZERO. It doesn't matter if it's a 124, a 123 or a dump truck. I've never used a spreader bar on my 124 and I've kept it adjusted such that I have had a minimal numbers of sets of tires in 300,000 miles. This car is the only one that has ever had a professional alignment and it was at an MB dealer where my brother in law works. I expect that they used a spreader bar, but out of curiosity I measured toe after I got it out of the shop and it was dead on zero by my measurement technique.

I can't imagine a loose idler arm having a significant effect on toe. If it were REAL loose, it might make measurements inconsistent. That said, I personally wouldn't be bothering to set toe with a loose idler arm or any other linkage component until the problem is corrected.

A loose idler arm will make the steering vague. We used to call it wandering or road walking. A loose tie rod end would be a totally different story. They should be tight!

I like the idea of tiles and grease as turnplates. From your post, it sounds like it works well. I've used sheet metal and grease and it wasn't bad, but a mess to clean up, so I haven't done it much. For me unless a car has been hit or is just doing something screwy, I keep the toe set on zero and don't check the rest of it.

Through the years even my high mileage MB's with some wear in ball joints have seemed to work well. As long as they drive good and don't have tire wear issues, I'm USUALLY good with it.

Even caster and camber being a little off usually won't cause any issues unless they are a strange combination such as significant differences in caster from one side to the other. Those kind of issues seem to only occur to cars that have had crash damage or cheap built cars that have spent lots of time on rough roads. In my experience, if you can keep an MB from getting wrecked and keep the steering linkage components tight and toe set, it will drive well and not have tire wear issues.

My $0.02,
Larry

Thanks for the spare change...

Like I say, both tie rods (complete) and center link are new / no play. So it's a pretty firm set of connections between the wheels.

I think I've got a little bit of wonder lust on the road you describe, and some inconsistency cropping up in toe readings varying a bit from park to park cycle. Hmm.


I'm going to get physical with the idler arm do a little crow bar push and pull on it, and check play in the steering box area as well.

In the meantime, thanks, I have stopped second guessing about toe-in and reset both to zero toe, went for a drive, steering wheel is straight, and is driving straight. But it's really cross-windy today... and w124 are touchy in this regard anyway.

I'm not sure about a diesel 124, but on a gas 124, the idler arm bushings are a bit of a trick. The bolt at the factory goes in from the top as it should, so that if the nut comes off it doesn't fall out. The bolt won't come out without lots of persuasion. It is commonly cut off with the blue wrench and then the new bolt put in from the bottom. The odds of it ever coming loose if tightened correctly are extremely remote if even possible.

If you want the bolt in from the top, it will require lots of messing around to do it. It's been a long time since I did so, thus my memory of the details has escaped me. Maybe a diesel is different because as I recall it is the exhaust manifold that is the interference on the gas car.

A good DIY Link
 

How I adjusted the toe in / out, camber and caster on my W123 300D
http://www.peachparts.com/shopforum/diesel-discussion/284337-how-i-adjusted-toe-out-camber-caster-my-w123-300d.html

More options
 

Recycled
 

for new members

FYI
 

More new tools to DIY wheel alignment.

wheel alignment gauge in Automotive Tools | eBay

https://www.google.com/search?q=wheel+alignment+gauge&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a


.

K-mac tons of camber lower control arm bushing
 

my 300TD was not alignable , camber not adjustable to factory spec

Now it is perfect after installing one of these, replaces factory lower control arm bush. Tons of Camber in any direction


K-mac its from Australia, $350 for two many years ago

Someone may not need those. And what is the price and availability now?