I'm getting better at suspension work, but this one has me stumped (I did try a search).

My wife's 82 300SD has a rattle that sounds like the front suspension. It's not real loud and it only happens on rough roads. I replaced the guide rod inmy 81 300SD a few weeks ago, so I know what that sounds like when it's a problem.The rattle is quick and constant on our dirt road, but rare on a hiway. It soesn't SEEM to be coming thru the steering.

I jacked it up and yanked/pried/jiggled everything I could see and nothing appears to be loose. The only thing close was the bushing at the top of the control arm- supports the sway bar - is a bit loose. But it's rubber and I wouldn't expect a rattle from it. Besides, it seems to be coming from the other side of the car from that one.

I can bounce and shove the car around and there are no noises.

I'm thinking:
A) I missed something or I can't put the necessary force on some of the parts to see if they are loose.

B) Something besides the suspension is rattling.

If anyone has a diagram (thought I had seen one posted here) for the front suspension it would be apreciated. I'll be getting the CD soon (I have the 123 CD that I would swap anyone with a 126).

Any ideas?

I also found a broken air filter mount on my 81, so I'll be ordering parts for that. Lookslike one of the bolts is going to be a bear to get to.

Thanks in advance.

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1984 300Sd 210k

Former cars:
1984 300D 445k (!!) (Strider) Original (and not rebuilt) engine and transmission. Currently running on V80 ( 80% vegetable oil, 20% petroleum products). Actually not, taking a WVO break.
1993 300d 2.5 275k. Current 120/day commuter
1981 300SD 188k (Hans) Killed by a deer

I pushed a thin wedge of soft wood between the air filter housing and the valve cover. That eliminated a lot of the rattling from my engine compartment. (My air filter bracket is broken off at the back, like a lot of them it seems.) The wedge has since been replaced by a piece of 1/2 inch thick silicone rubber, epoxied to the side of the filter housing. I also find that the lower bolt on the air cleaner bracket was just loose enough to allow slight movement of the bracket. It was just enough to feel when yanking on the bracketby hand, but tightening it definitely eliminated some of the noise under the hood.

On the front end, I found that the bolt that attaches the front swaybar to the upper control arm was loose on the passenger side of my car. Tightening it eliminated a bump-induced clunk that I was positive was coming from the back.

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1985 300SD, 203,000 miles, dark blue

Lil Sarah says: "Poor old Grandma Blue Car...She's sad."

I would check the lower balljoints again. I thought mine weren't too bad because a good shake under the tire didn't seem to show any play and there wasn't any steering wheel shake like a lot of other cars get when the ball joints are beat. It clunked pretty good moving along a dirt road but seemed fine on the highway. When I finally got under there by removing the wheel and supporting on the steering knuckle, I could clearly see the play. Quite a difference now that I've changed them.

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'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

Read this thread, and on page 2 there is a great diagram...

http://www.peachparts.com/shopforum/showthread.php?threadid=90724&highlight=rubber+bushing+replacement


Good luck..

The suspension on the W123 and the W126 are almost identical except for the brake mount support, also called the guide rod mount. The W126 has a different unit. Otherwise everything else is the same.
As posted check the ball joints. and possibly the shock absorbers may be going internally.
Use a pry bar and see if any of the suspension bolts are not fully torqued.
Also don't forget the sway bar mounts

http://207.210.95.34/~boostd/

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

I chased down a similar problem on the SDL. It wasn't exactly a rattle, sounds more like someone rapping on the undercarriage with a hammer. Like yours, it is somewhat random. Doesn't happen all the time and doesn't ever happen on the highway.

Found out that the bracket and bushing that secures the sway bar to the body on the right side is trashed. The bar is banging on the body at certain times. The vehicle also pulls to the right because the sway bar is not providing resistance to prevent the upper arm from moving rearward on braking.

This bracket is directly below the battery tray.

OK, I found the rattle, just in time for a long vacation drive. With my son jumping up and down on the front bumper, I could see the bottom shock mount moving and clanking. I searched this forum for advice on how to get the shock off (loosen the one you can get to with a 12-point socket, then take off the top mount, push the top through the hole and pivot shock to get out the other screw). The threads were beat up, so I bought the correct tap and cleaned it up (8mm). Put in new screws and no noise!

__________________
1984 300Sd 210k

Former cars:
1984 300D 445k (!!) (Strider) Original (and not rebuilt) engine and transmission. Currently running on V80 ( 80% vegetable oil, 20% petroleum products). Actually not, taking a WVO break.
1993 300d 2.5 275k. Current 120/day commuter
1981 300SD 188k (Hans) Killed by a deer