Shaking it Up!

[bwheitman]

Hey Friends,
I got myself a 96 SL320 last fall. I have spent tons of money and time getting it back in shape and it is really coming along nicely, such a great car!
Last Sunday afternoon I removed my hard top and started driving it with the soft top. The car shakes and rattles crazily! The sun visors shake and rumble everytime I go over bumbs. Unlike some of you with more than one SL in your garage, I don't know if this is normal? do I have something loose in the undercarriage? Do I need to have it looked at? Any ideas? stiffen the frame? I put new tires on it and balanced the wheels thinking that might be it, but still it shakes when I go over bumps. Maybe I should ask to test drive another SL this weekend to check it out. Let me know what you guys think! it has 103k on it.
Brian

[elau]

That is not normal. The car should not shake like that at all. With 103k miles on the clock, you may have to replace your shocks.

[bobterry99]

I don't notice much in the way of rattles, but I believe these cars do exhibit a noticable amount of "cowl shake" which was commented upon here. Since that post I have owned three more 129s and they are all similar, but maybe not to the degree bwheitman describes. I would definitely recommend driving another SL and comparing.

[LeaUK]

All convertibles suffer this shaking to some extent or another - it's called 'Scuttle Shake' in the trade.

The SL's shake is minimal and should hardly be noticed - however, I do find the ride slightly better when the hard top is on. Scuttle is reduced to zero as on most conventional coupes.

If yours is particularly noticeable it's time to start checking things!

[jjrodger]

I agree with Learoy: if I'm really, really hammering it (like driving as if I'm on a track but on bad roads), I get scuttle shake. Otherwise this car is so solid. I did 145mph today for about 5minutes on the A1 between Morpeth and Alnwick today (look it up) and it was ultra solid.

[bwheitman]

I put my car up on Ramps and checked it out underneath. I noticed that there are two thin bars that connect to the center crossmember under the engine and go out diagonally to the outer part of the body. The bar on the passenger side is bent. The majority of my shakes reside on the passenger side of the car and they make their way accross. I am going to remove these stiffening bars(?), straighten them out and then remount them. Or should I buy new ones? and how did it get bent? It only has about a slight bend in it, not much. I ordered a new set of wheels too, so those may help as well. I had the entire undercarriage checked when I bought it and they just recommended alignment as well as repairing all the oil leakes it had. I put the hard top back on, I love the car with the top down, but it drives so much better with the hard top mounted. I will keep you posted! Thanks
Regards,
Brian

[bwheitman]

I put the car on ramps and climbed underneath. I straightened the "stiffening" bars,while I was under there I noticed that the flexdisc behind the transmission was failed. There was nylon all over and it was near total failure. I removed it and then will go and get one in the morning. I am sure glad this didn't fly out while driving. So if any of you great Mercedes drivers experience any vibration, take a look at those flex discs! I will let you know if it helps the cowl scuttle too.


Brian

[bwheitman]

So far I have new tires, wheels, alignment, and replaced both flex discs. The car drives so much better and feels really solid on the highway, only a slight vibration.
My experience has been with all the Mercedes I have driven, that is if you have a vibration, a noise, or a rattle, find out what it is, because it is usually something major!
The only thing I am worried about now is at low speeds 3-5 mph, a light right turn I hear and feel a grinding noise, new brakes and bearings, so that is not it, had PS fluid replaced, you can feel it right in the footwell, right where the steering gearbox is mounted, any ideas? Thanks for all the help!
Brian

[jjrodger]

Cat heat shield?

[bwheitman]

I checked the heat shield, no problems. I did notice that there is a little bit of rubbing in the rear wheel well on the subframe, could that subframe be moving? The car still shakes with the hard top off. I can't drive it on the highway without the hard top, it is annoying. It is going into service for it's 105k and that includes a chassis inspection, so I hope they find out what is wrong. At least the problem has led to correcting other problems so far.
I will keep you posted.
Brian

[bwheitman]

I was reading this post and realized I never posted my fix. The problem with the shaking was the fact that I would not allow any wheel weights on the outside of my rims. The prior rims were ruined because of it. Mercedes put clip on weights on that they say will not damage the wheels, the car no longer shakes. There is a little cowl shake with the top down, but other than that it is perfect! They also checked the chasis, the engine, suspension, and transmission, they say everything is in great shape. I think it will last for a few more years!