I recently purchased a 1984 300D. It was a one owner vehicle, and, in general, was well maintained. However, the car wanders all over the road! The front tires are worn and feathered with high ridges toward the outer edges. I looked at the front-end last night, and the upper control arm bushings look okay. The lower ball joint boots are torn, and, therefore, need replacement. I understand that worn guide rod bushings can contribute to the wandering problem. I'm willing to tackle the ball joints and replacement of all of the bushings, however, before I start I want to be sure that I don't actually have some type of steering problem, as I'd hate to invest the time and money and not solve the problem! I would appreciate any input anyone would have as to how to properly diagnose front end issues with this vehicle.

I did the complete front end job about a year back then went to get alignment at sears, they totally messed it up, went back again within warranty period and they fixed it somewhat. Now the car does the same thing like yours. I think its bad alignment. So in your case too it can be same problem.

MVK

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One penny saved is three penny earned.

1985 300D Turbo 179,000miles

I would start by replacing the items with the torn boots on the front end. Also, take a good look at the track rod mounts and make sure they are not deteriorated. How do the boots on the tie rods look? How does the steering shaft coupling look (between the steering column shaft and the steering gearbox input shaft). AFTER you insure all this stuff is in order then you can go to your steering box (drivers side, mounted on the inner fenderwell accross from the oil filter housing). Loosen the locknut and turn the allen head adjustment screw 1/4 turn counterclockwise and then tighten down the locknut. Take it for a test drive. If the steering wheel still moves over 1" before the front end changes direction, adjust the steering box again. Keep this up till you get it where you move the steering wheel less than an inch before the front end changes direction. Don't overdo it.

Personally, I do not screw around with steering/front end stuff because of the safety aspect of a failed system while driving. I have seen an old GM POS going down the road and lose a tie rod end - it ain't a pretty site.

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Jim

Toe in is too low (both tires point toward the center of the car). Makes for wihte-knuckle steering, may be there to compensate for wobbly ball joints. Car will be VERY sensitive to cross winds and won't respond well to steering input. Tires pointing out will cause the same, but "oversensitive" steering rather than slow.

If the ball joint boots are torn, they need to be replaced, they will go bad if they aren't already.

The track rod bushings will knock or groan (or both) going over bumps like speed bumps if they are worn enough to cause wander.

You need to check the entire steering mechanism before deciding what to do, and in what order.

Steering box -- must have very little play, can be adjusted per Jim's instruction. Note following before adjusting.

Steering coupler. This goes between the steering column and box, has two rubber bushings on steel pins. When the bushings go, the steering wheel gets " loose" from the sloppy connection to the box. Will cause the wheel to rattle and snap on rough surfaces.

Idler arm bushings. You should have no more than barely perceptible vertical movement of the idler arm. Any more and you need new bushings.

Drag link ends -- no play, if you feel or see any, replace drag link.

Tie rod ends. Ditto, replace if boots are bad, too. Much easier to replace the whole thing with both ends than to get a rusted end off, and the alignment shop will thank you.

Ball joints, upper and lower. No side-to side play, lower joint can have a couple mm vertical play. Jack wheel off the ground and pry tire straight up to test.

Wheel bearings. Should have about 0.001" free play cold. If loose, adjust, then re-check in a couple thousand miles. If loose again, replace.

Upper control arm (sway bar) mounts -- if they are worn, the caster changes with load, makes the car steer funny.

Have fun!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Again my gut feeling says Toe-in angle is not set right. But both Jim and Peter have the right approach for you.

MVK

__________________
One penny saved is three penny earned.

1985 300D Turbo 179,000miles

That sounds exactly like mine, my tires are worn unevenly, but I don't want to get an alignment until I replace all the components with cracked boots. There is no play in any of them yet, but I seen two cracked tie rod boots and a ball joint.

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Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k