Alignment and Control Arm Bushings -- Relevant>
 

Car:
2008 E350 4Matic Sport
85,000 miles

I went to get an alignment (top of star on steering wheel is sitting between 11:30 and 12:00 when driving straight) and was told by the particular shop that they could not do it because of some cracks in my lower control arm bushing.

Since this car has no camber control, and since the steering wheel issue is almost certainly related to tie rods, can someone perhaps explain what I was told?

I have never heard of such a thing.

It means your control arm bushings are roached. They're not going to align it because the control arm is moving more than designed and renders the alignment pointless. It's a waste of their time and your money to align it without fixing the control arm bushings first.

Not sure what roached means but the cracks are small and that is a Long piece of rubber that is still (almost) entirely intact. When it goes, it will be unmistakable. (I am having front axles replaced right now and tech pointed out that the busing is nowhere near worn enough to be of concern.)

My thing is, all I need is a Toe adjustment, so how is the control arm relevant? (With hands off wheel, car tracks straight, despite the cocky steering wheel. )

The control arm bushings fail gradually. Ask any W12x owner the difference they felt when they replaced their "ok looking" control arm bushings.

Cracking means they're hardened, compressed, and at the end of their useful life. Rubber ages in addition to wear. When the control arm bushings wear out or sag, the suspension geometry is all affected. Under the weight of the car and acceleration/braking forces, the control arm is free to move fore and aft to much more degree than it is with good or new bushings.

A reputable shop won't perform an alignment on a car with visually worn suspension/steering components. It's a liability for them if something goes wrong.

If you want to kick the can down the road for a while, find a chain alignment shop like a Firestone, they'll align anything whether or not it's worth your money or their time. Just keep in the back of your mind that you should budget for control arm bushings in your future.

I understand.

Perhaps I was making the wrong request of the shop. I should have instead asked them to adjust the tie rods so the steering wheel would be straight since alignment is otherwise perfect.

If that's all you want you can easily do that yourself. You just need to adjust one tie rod in a little and the other one out the same amount. You can mark the nuts and count rotations. It takes a little thought but it is not rocket science. It's tie rod science.

On Tuesday or Wednesday am am replacing my engine mounts and may give that a try. I imagine the right side would need to be made slightly longer and the left side slightly shorter(?)

Also, is it possible to partially unbolt and lower the control arm just enough to have free access to the bushing? (The arm says attached to the car.) If so, it would be more than worthwhile to buy the special tool made by Baum to push out and install the bushings myself. I saw it done on a RWD car and it took only a minute or two each for removal and installation.

Disregard this. It seems only the strut needs to be tilted out of the way to push out/install the bushing. (Hard to believe repair shops want $1500 for this)

The opposite. Look at it this way: If you put the steering wheel "straight up" then you will be going a little to the right. So you need to point each wheel a little to the left. Put paint marks on the adjusting nuts so you can keep track of them. I would start off with one full revolution of each nut. That should get you very close. Then you can calculate a second adjustment if necessary. Keep in mind the threads are right hand on one side and left hand on the other side (I think). Just keep track of what you are doing. I used to live in Greenbriar BTW...

Yeah, that's just me (incorrectly) determining left/right standing at the front of the car, looking into the windshield.

I will give that a shot. I am not going for perfection; just adequately closer dead-center than it currently is. If one turn does it, I will be happy.

(I pass Greenbriar almost daily.)

You can use a paint pen for this, or give each nut a quick shot of white or yellow spray paint (allowing some spray to fall into the exposed threads) on one side of the nuts the day before you work on it. Observing the paint makes it easier to return the nuts to the exact original position if you loose count and need to start over, just don't get so much on the threads that it interferes with adjustment. When you're done centering the steering wheel, you'll have one circle of paint split into two halves on one side of the car, and a slightly oval circle of paint on the other side (where the painted areas now overlap).

Excellent idea. I will do exactly that. Thanks!

When you shoot the spray paint, you could mask off the top and bottom so you create a rectangle. That way you have a hard top and bottom edge to make it even easier to align if you need to return to "zero".