Help: 87 300D alignment question

No, positive toe-in means the leading edges of the wheels, not the tires, are closer together than their rear edges. That specification allows the tires' rolling resistance to tension the steering mechanism so the wheels will, in fact, be parallel while driving. Toe-out will set the leading edges farther apart from each other than the trailing edges of the wheels. I've never seen a toe-out specification.

The rear wheels also have a toe in which is established by the car's height vs. the camber angle of the rear wheels.

TG,

Thanks for clearing that up.

Now can you give an opinion of this situation:

Just by looking at the wheels from different angles, I can see that the left rear wheel is overly towed in. So, I setup an alignment test in my garage as per this guys procedure

I carefully did the setup and measurements two times and both times I got the same toe-in results:

IN DEGREES LF .223° RF .223° LR .67° RR .223° TOTAL FRONT TOE-IN: .445° TOTAL REAR TOE-IN: .893°

IN MINUTES LF 13.4' RF 13.4' LR 40.3' RF 13.4' TOTAL FRONT: 26.8' TOTAL REAR: 53.4'

The car pulls to the right. And the RIGHT rear tire is slightly wearing on the INSIDE. Does this make sense?

Bill

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First of all, the procedure in the cited url omits something that you should know. He omits a important fact - a car's front track and rear track are rarely the same, M-Bs usually have a wider front track than rear track so setting a string parallel to the car's body is crude at best - but better than nothing.

I check and adjust my cars' toe-in a crude but quite effective way. I drive it into the garage with the steering wheel at dead center and stop the car with the parking brake, not the regular brake. Then I set a vertical stake about 3" from the center of each rear wheel and then hold a 2" wide 12" long level horizontally against each front alloy wheel, I sight down the outer edge of the level to the inner edge of the stake 3" from the rear wheel. This checks each front wheel's toe-in vs. its rear wheel AND against the steering wheel's dead center position. Thereby I treat each front wheel's toe-in individually. The front wheels' caster and camber are adjustable on the older models via eccentric bolts on the lower control arms and struts. I've adjusted these on other cars but find it too hard (for me) to undertake on my M-Bs. I've found my E320's steering is quite sensitive to toe-in, its caster and camber angles are reset (if necessary) with a dealer supplied kit.

On to your car. IMHO if the LR toe-in is really 3x that of the RR it seems to me that the LR tire would have the inside tire wear and that the car would self steer to the left - because the LR tire is steering the rear of the car to the right which causes you to steer (the front) to the right to correct the front's bias of having been aimed to the left by the back wheels.

I suggest you measure your car's height at various places in the rear because the height determines the toe-in. Height to the lowest part of the sub frame and height to the forward pivot point or sub frame bushing. If the side to side difference is more than 1 inch the toe-in may be explained and the heights should be corrected.

Otherwise, worn out bushings in the rear suspension will allow the wheels to drift from specifications. I'd check if a rear wheel shifts its position as the transmission is shifted (at idle) between D and R with the brakes off and the front wheels blocked (don't try this inside the garage!)

I hope this helps you. Tom

Actually, the Russ procedure (web site) does compensate for the difference in track between front and rear. The initial string (fishing line) is set 2" out from the exact center of each wheel. Then plum bob mark the floor at the string just in front of the front tir, each side, and just behind the rear tire, each side. Then measure the distance between the marks in front, and then the back. The rear track on my car is 3/8" less than the front. So I moved the rear strings out 3/16" on each side to establish the parallel lines.

I am going to measure the height tonight. And repeat the complete setup/measurement from scratch. If it comes out the same, I think I am going to try correct the LR wheel from .67° to .223°. Only problem is I will have to jack up the car to do it.

Thanks for the response.

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