She go left when I accelerate, right when I coast

[patbob]

I discovered this on the way home last night. My car (1983 300D turbo) does it on different streets and at different speeds. It even seems to be doing it as I go around curves (although it's harder to tell then).

Does anyone know what else I should look at, besides the rubber in the rear suspension, for the cause? I noticed this morning that my 1984 Volvo 240DL also does it a bit, so could it just be a consequence of rear wheel drive?

The folks following me last night probably thought I was a crazy driver or worse . Was a pretty good cure for tailgaters, just not one I care to have anymore.


History:
I've been slowly working my way through the steering problems on my car. The symptoms are that the car drifts to the right a little and the steering feels a little loose. Not enough that it feels like it is pulling, more like just enough that I have to compensate by turning the wheel to the left enough to remove the slack in order to keep it going straight.

I adjusted the steering box until it has about the 1 in of play (it had tons more when I got the car -- somebody adjusted the screw in the wrong direction). I replaced both upper control arms because I found play in the passenger side ball joint. I replaced the idler arm journal bearing because it too had play. After that, it drove great for about 50 miles.. steering was off, but was tight. Then it got worse again, the driftiness and looseness came back. Last night I noticed the left/right acceleration-related pull. I have yet to get the car aligned -- it was next on my list of things to have checked.

The tire pressure is spot on (I keep checking it thinking maybe they've lost air and are now the cause of the problems). The outside edge of front passenger tire is practically bald, but it always looked like it might have a slight outward camber to it until after the UCA replacement. I wanted to fix the looseness or rule out all other possibilities before buying new tires.

[rrgrassi]

Check for play everywhere, guide rod bushings, UCA and LCA bushings, rear bushings, etc.

[R Leo]

On a Benz, the problem you describe is almost directly attributable to a bad subframe bushing...probably the left one.

[barry123400]

I would perhaps be quite suspicious if the car drove fine for fifty miles and reverted to it's former ways.. Alignment problems could contribute to some of your problem as well. Either way I would get this car up on a hoist and check out alll suspension components. Some with a pry bar if indicated.
You mught check your upper sway bar mounts, bushings etc. before the hoist work. Use a little pressure to make sure everything is solid. Also make sure no suspension point is semi mobile because of invisible rust hidden under the undercoat. Those guide rod mount points should be really solid. Your initial description would make me check the rear end area as carefully as the front. Something is probably moving too much under pressure. Use a pry bar. R.Leo is mentioning the type of thing to look for that is bad if not the actual item.

[toomany MBZ]

Sounds like a half shaft issue to me. When acceleration forces are applied to one side only, will cause a "steering" condition to occur. Checking all bushings a good idea.

[patbob]

Originally Posted by R Leo

On a Benz, the problem you describe is almost directly attributable to a bad subframe bushing...probably the left one.

Thanks. That's what my reasoning tells me too. It is appreciated to have confirmation

Originally Posted by toomany MBZ

Sounds like a half shaft issue to me. When acceleration forces are applied to one side only, will cause a "steering" condition to occur. Checking all bushings a good idea.

I'm not sure I follow. Are you suggesting that only one rear tire is getting torque/drag from the engine? Or that it is uneven due to a differential problem? Or is there some other half shaft type problem you're thinking of?

What should I check/What kinds of things should I look for?

Originally Posted by barry123400

I would perhaps be quite suspicious if the car drove fine for fifty miles and reverted to it's former ways...

get this car up on a hoist and check out alll suspension components. You mught check your upper sway bar mounts, bushings etc...

make sure no suspension point is semi mobile because of invisible rust hidden under the undercoat...

Yeah, you and me both Barry,.. I'm very suspicious of the change after a few miles The car creaks in the back as I jack up the front to work on it. I hadn't gotten to looking into why just yet. Now I think of it, its probably related :doh: (where's the simpson doh smilie when you need it?).

I only checked one sway bar mount on the front.. it was OK. I'll check the other on the front and the rears too. Thanks.

Invisible rust.. now that would really suck. I'll keep an eye out for that too, but with the way things are moving, it'd probably already be a rusty hole. Fortunately, of the stuff I've checked on the front, all is good on that account. Keeping my fingers crossed the rest will be fine too.


Thanks all for your suggestions. I'll report back here after I check it out.

[300SDog]

Rear wheel allignment too, thats something alot of shops forget.

[MBeige]

Originally Posted by 240Dog

Rear wheel allignment too, thats something alot of shops forget.

I don't think the rear suspension is adjustable on a w123. Maybe you mean thrust angle?

[R Leo]

Originally Posted by 240Dog

Rear wheel allignment too, thats something alot of shops forget.

Can't be done on a 123 or 126.

[toomany MBZ]

[quote=patbob;1415030]


I'm not sure I follow. Are you suggesting that only one rear tire is getting torque/drag from the engine? Or that it is uneven due to a differential problem? Or is there some other half shaft type problem you're thinking of?

What should I check/What kinds of things should I look for?

Do you hear anything unusual from rear? Sound may be masked by ambient noise. Doubtful it's differential related, as you probably would not have any drive. I am suggesting partial, or no power to only one wheel. How are the conditions of your boots on axle? If you jack up rear, securing with quality jack stands, of course, you should be able to test for failing CV joint. Some rear ends will drive both wheels, start, put in drive, see what happens. With tranny in park, (might as well shut off engine) try to turn wheel. Moving a very little, okay, if you hear, or "feel" anything that sounds like bad news, it probably is. Hope this helps.

[patbob]

Originally Posted by patbob

Thanks all for your suggestions. I'll report back here after I check it out.

Well, I managed to check out my car... Found some amazing things, but no real smoking guns as it were.

The only things I could detect that were wrong are:

• The front subframe bushings seemed weak -- I could see movement in both (more on drivers) just by pushing on the wheel. Seems too easy to resist the forces of accelleration so they go on the list.
• The steering damper shock is worn -- it gurgles when I turn the wheels.
• The car has four different brands of tires on it (five if I count the spare). That'll cause wierd problems too. Gotta be some kind of record there. I'm also ashamed to admit I hadn't noticed. Guess I'm the new recipient of the IDIOT award
• The front LCA rubber bearings (both sides) need to be replaced. I can't get any play from them, but the rubber doesn't look in great condition.
• The front, drivers-side tortion bar rubber bearing is worn (passenger side is OK), but I don't think that would cause the problems I'm having.

So, looks like I'm in for:

1. Rear subframe bushing replacement.
2. Steering damper.
3. New set of tires and alignment, where I suspect the rest of my list and maybe more will happen....
4. Front LCA bushings.
5. Front lower ball joints. I can't get any play from these so they may be OK, but as long as the spring is pulled and the LCA off, it's time to do them too.
6. Front tortion bar bearings, although I doubt the extra 3mm of vertical play in the drivers side one could be the cause of my problems.

I'll drop by this thread and report back as I get the work done in case anyone is interested in what it ends up taking to correct the problem.

No matter how I slice it, this is still way cheaper than car payments

[peterhardie]

I would start with #1, before you spend tons of money unnecessarily. I had the exact same problem with my wagon, new rear subframe bushings fixed the problem.

[bodyart27]

I just rebuilt the front end of my 126, and though I had the dealer do the alignment (they put some cross ???? whatever to compensate for the pull to the right) it is still not right.

I just picked up my subframe bushings and trailing arm bushings yesterday, so hopefully I can get some time Sunday to put then on.

On my car the rear just seems "loose" and squirely. Maybe these cars are like this, but if I do quick left to right to left to right steering inputs at speed it doesn't feel very reassuring back there (wallows?).

I also have a speed sensitive pull. Lower speeds, not too bad, highway speeds, it wants to pull right.

Just this morning I noticed an acceleration noise. Like drivetrain noise when I'm on the gas, and a reduction of noise when I lift. Maybe normal - just grasping now. Maybe at Leo's GTG I can ride in someone else's 126 and get a baseline.

I'm crossing my fingers it's the rear rubber. I'll let you know in a week or two (when I can get some time - wife doesn't like it when I do marathon weekends in the garage) what I find out.

[peterhardie]

A few days before you attempt your rear bushings, spray the heck out of them both with some good penetrating oil. Drive it, then spray it some more.

More than a few are seized, rubber to metal. Go slow at first with that main bolt.

[patbob]

Originally Posted by peterhardie

A few days before you attempt your rear bushings, spray the heck out of them both with some good penetrating oil. Drive it, then spray it some more.

More than a few are seized, rubber to metal. Go slow at first with that main bolt.

Thanks for the reminder. I usually try to fit that into my mental schedule, but already forgot. Anything that makes the job go faster is always a win for me