Well I'm stumped. This is the 84 300SD.

Car was pulling right on a long road trip last week and I stopped at an NTB to have it checked (I have a 5 year alignment with them). The guys were helpful in spotting some issues.

One issue was that the right side upper control arm boot was split (not dry, still had grease, but split). Second, my idle arm was pretty shot - a lot of play.

I figured the idle arm was the culprit. My tie rods had been replaced last year and the steering box was a new "rebuilt" unit so it was tight. No wheel bearing play.

I swapped upper control arms on both sides (did the sway bushings that attach to the arms as well since I was there), and did an idle arm repair kit as well. Now the idle arm is solid.

Had the car realigned and everything was set to spec (rear was fine - front needed only minor adjustment tweaks to both tie rods). Technician didn't identify anything else "loose."

Car still pulls right. I've swapped tires (which are new michelins - only two months old) left to right and front to back. Pull does not follow the tires.

Also, at low speed (cruising around neighborhood less than 30mph) and under braking, the car tracks pretty straight. The pull seems to really make it self known at speed above 40mph.

The only thing that looks suspect is the bushing on the right "brake support link?" (not on the end where it connects to the lower control arm - the side that attaches to the chassis). With the front end up on a jack, I couldn't figure out how to jiggle/push/pull the suspension correctly to see any movement or play on the brake support link. Any good way to check this?

What should I check next? Only thing I can think of right now is to take it to another NTB (since I have a warranty), and get another set of eyes on the suspension and see if they can spot anything else and recheck the alignment setting.

Thoughts?

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~shell
As of 2/2010:
2001 CLK55 0o\=*=/o0
13.6 @ 106mph
10K mi
1984 300SD
260K mi and going and going...
97 S600
46K miles
1991 Sentra SE-R (extremely dorked with)
www.se-r.net

Wheel bearing?

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-1983 VW Rabbit LS Diesel (5speed, VNT/Giles build)

You are assuming they know how to align a Mercedes. Many of us only trust a dealer to align their MB's.

That would be my suggestion. In my area only about $80 bucks.

Steve

I agree with both of the above suggestions....

You may want to read this article.

http://www.continentalimports.com/ser_ic4232.html

Steve

If a brake caliper was dragging, you'd smell it. Wheel bearings should not have any "say" in steering. I had a failure at interstate speeds. No pulling, no warning, just POW! Only an $1100.00 rebuild, I don't use that mechanic anymore. I'll go with alignment, a friend had the same thing, he went back to the alignment shop, they re-did the front end, now it's fine. On most cars there is a large "window" to set front end, on MB's, rather small. Hope this helps.

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83 SD

84 CD

[QUOTE=toomany MBZ;1382689]Wheel bearings should not have any "say" in steering. /QUOTE]

The " shouldn't " but they do...
every manual I have ever seen said to check and set the wheel bearing clearance before trying to align the vehicle...

I understood to check, jack up front, grasp outside of tire at 12 o'clock and 6 o'clock, move in and out, to see if there is any play. I don't understand how to set clearences on wheel bearings. I thought you greased 'em up, put 'em in, tightened lock ring somewhat, put the cap back on, that's it. Interested in knowledge.

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83 SD

84 CD

These German Engineers were a " little " " retentive" if you know what I mean...

On my 81 wagon they had a crush washer ( which could only be used once )... so you put the specified type and amount of grease in the right places... then you put the hub on and use a dial indicator to determine how much you tighten the hub nut. ( as careful as I was progressing I overdid it a few thou and had to go back to the dealer and get some more... I got ' spares' the next time.. it was a 30 mile each way drive and had to wait till they were open.
In the old days on American cars you could use a torque wrench and take it to a specified reading ( to be sure you had squished the grease ) then back off the nut a 16th of a turn or so ... that is just generically talking.... everyone had different specs...
But MB wants you to be way tighter with their wheel bearing readings...

are you driving on a two lane road?

if so it will pull quite a bit due to the crown in the road. try driving onthe left side of the road and see if it pulls to the left equally.

when there is no traffic and you can see a long way.

i am always amazed at how much they pull on a crowned road. it is due to the relatively large amount of caster they run.

tom w

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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.

It took three tries to get my SDL aligned so that it didn't pull to the right. Finally, they adjusted the right side so that it has slightly more caster (I have the numbers in the car and will post here later) than the left. The FSM doesn't specify that sort of 'stagger' but my particular car had been wrecked in the past which I suspect has something to do with it. Anyway, the car tracks stright and doesn't wear the tires so something is right.

You should know that Mercedes' alignment adjustments are closely interrelated which makes the cars are tough to align properly; for example, not many cars have as much range of caster adjustment as a Benz. Even a person's weight in the driver's seat or a slightly under inflated tire can make a huge difference in how the alignment looks to the alignment machine.

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Never a dull moment at Berry Hill Farm.

If the brake link or guide rod bushing is really, really bad, you'd notice a clunking under your feet or the passenger's feet when you apply the brakes. In worst-case scenarios, it might even pull in the direction of the bad bushing.

The alignment shop 'should' be able to tell you if that bushing is bad or, you can pry on the rod with a long screwdriver at the bushing (chassis) in a fore-aft direction. No movement should be possible. If the boot on the bushing appears torn, then it's shot. Plan on replacing both sides. You can replace these parts w/o a spring compressor but a big vice and a workbench is nice.

Look at this thread to see what they look like when worn REALLY bad.

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Never a dull moment at Berry Hill Farm.

I have also noted this.......and have a nice straight section of road where I check this......

SB

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Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

Did they give you an alignment sheet telling you what everything is set to and what everything should be set to by factory spec?

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1985 CA 300D Turbo , 213K mi

Personally I don't trust NTB. I replaced a rack and pinion on father-in-laws car and told the mechanic. His approach was to just turn the rack until it came close to spec. I didn't realize until I got the car home that only 3 threads were holding the tierod to the knuckle. could have been disasterous. Also when he turned the rack the rubber boot wound up so tight, I'm surprised it didn't break. GRRRR

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Closing the store
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