When I first got Hans, two of the air cleaner mounts were broken causing the air cleaner to dance all over the place and make a racket, especially when cold. I replaced the mounts and all was well, except that I noticed the elbow that attaches to the turbo inlet was not tight and was moving all around - there was no more thread left to tighten.

Then the mounts broke again 4 months later and I replaced them.

Then last week, the bracket itself broke.

I was torn between spending about $65 for a new bracket and mounts or just going with the K&N type mod and trashing the original air box. Looking through the PO records, the bracket had been replaced 2 years ago, and maybe a total of 6 times over the years. But I know the MB engineers designed the airbox for maximum performance and flow, so I didn't really want to mess with it. And there are questions about K&N filters allowing too much dirt in.

As I watched the air cleaner as the car was idling, I noticed that it vibrated at the same frequency as the engine, but not in the same phase. In other words, the air cleaner, only being held to the engine by three flexible rubber mounts, was in effect, moving the opposite direction at each pulse as the rubber stretched and contracted. No wonder the mounts and brackets didn't last long.

Last night, I decided to try something. I took off the air cleaner assy and removed the clamp at the elbow. I then put on a stainless steel hose clamp, size 2 1/16" to 2 7/8" and snugged it. I replaced another bad mount and reassembled the air cleaner. Then I tightened the clamp around the turbo and started the car.

What a difference! Even with only two rubber mounts (the rear one can't be used since the bracket is broken) the air cleaner assy doesn't move at all.

The clamp on the elbow is needed to attach the air cleaner to the engine as much or more than the rubber mounts. A peek under my wife's 300SD showed hers was loose also. This may be a common problem and a reason the mounts/brackets don't last long.

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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