84SD follows road crown more than modern cars. It is only what I consider a slight pull but it is definitely there and would be tiring on a long trip.

The front suspension has been refurbished with ball joints, control arm bushings, just about all except swaybar bushings and tie rods which were good and will be done whenever needed.

What effect do worn rear suspension parts have have? New Bilstein HD shocks are also done.

Might more caster help? Settings were near the middle of specs the last time it was aligned.

I would put new springs on it.... the ride height affects everything.
then start looking at the specifics that are causing that pull....
does it pull on a perfectly level surface ?

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Check your tire pressures. If they are overinflated, it will cause a considerable amount of wander. I always use the recommended pressures posted inside the fuel filler door.

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Sam

84 300SD 350K+ miles ( Blue Belle )

Mine does not pull. I suspect caster helps as the alignment fixed a lot of mine.

Fresh forward subframe bushings in the rear of my SDL helped. The ones under the rear doors with a 50 caliber bolt.

I don’t recall that wandering or tramlining got worse in the SDL with higher than spec tire inflation, or in the ‘83 SD with 420SEL rear springs and Bilstein comforts. In fact the SD felt steadier with those heavier duty springs even with no load.

Sixto
98 E320 sedan and wagon

Caster, as I understand things, does not cause or enhance pulling to one side or the other. Camber is the biggest contributor to that - think of leaning a bike over to one side or the other while riding; it goes to the side you are leaning towards. Toe that's out of spec will contribute to wandering, and a mushy on-center feeling.

What caster has to do with is the self-centering of the steering, and understeer/oversteer. Looking at the wheel from the side, caster is the angle of the axis the wheel/hub rotates on while steering. There are many sources of information about wheel alignment online, describing what the adjustments are and how they affect things.

Yes, worn rear suspension can cause a pull. Bad control arm bushings, bad subframe mounts, etc. can contribute in weird ways.

You could swap the front wheels side-to-side, to see how that might change things. If it does then you are looking at a tire issue.

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- Greg -
1973 220D, The Prodigal Benz
1974 240D

It drives very well on level roads. It has a slight pull to either side depending on the slope of the road. It does not consistently pull to one side or the other the way uneven tire pressure or bad tires do.

All front end parts except springs, sway bar bushings, springs and tie rods have been replaced. Tie rods are not very old and were recently replaced.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

Mine did that, never got it fixed.

Lmg is saying that New springs, set to correct ride height, and rear bushings would prevent the wander most likely.

It makes sense, as the rear being squishy, would cause tilt on the crown causing you to steer into the twist...

Look at the diff mount, and the trailing arm bushings...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Sounds completely normal to me. All of my properly aligned vehicles behave that way.

What about the shocks/dampers? Did you replace them? Good ones make a big difference in ride and handling at all speeds.

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- Greg -
1973 220D, The Prodigal Benz
1974 240D

I have been told it’s normal, but few of my vehicles do it.

If you increase the vehicle camber, it reduces road steering, but increases steering effort.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I think its normal for a mb too. They have more caster than most cars. This will produce more pull on a crowned road. The trade off is very high stability going straight and better turning response as the wheels lean over into a turn to offset the natural sway.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

When you solve this or consider it a part of MB's design will you please send me a PM? Lord willing I'm going to start a restoration of the suspension on my early w126 as soon as I finish what's on my list.

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84 300SD
85 380SE
83 528e
95 318ic

Excellent 5 minute read on alignment angles including road crown pull and how caster splits are used to correct.


AGCO Automotive Repair Service - Baton Rouge, LA - Detailed Auto Topics - Wheel Alignment, Camber and Caster

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Paul

Indeed. Thanks for sharing that. I'd not considered the relationship between camber and caster in that level of detail. I've read a decent amount but nothing that ties things together as well as that article. I'm going to chew on it for a while . . .

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- Greg -
1973 220D, The Prodigal Benz
1974 240D

I intend to do the rear bushings this summer since I know that nothing has been done. Trans and diff mounts were included in my original "bring it into reasonable condition tasks" when I bought the car.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.