My mechanic says that the humming and buzzing noise is due to this part which needs to be replaced.. any ides where I could possibly get one ??

 

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www.mymercedesparts.com

Have your VIN ready and Jeff and his folks will get you what you need! They are extra careful.

 

Have Jeff or anyone email me at steadystud73@yahoo.com and I will provide them the VIN number.

 

photos are being moved to the "other forum"

 

Sorry, can you post a link to where the pictures are at?

 

I can't get the ****ing damper off the valve unit, it's will not budge. Any suggestions? I'm using a 24mm wrench and the thing just will not turn. Also it's on some rubber mounts which makes it even more painful.

 

maybe modify a crow's foot to put on a breaker bar if you cant get a cheater pipe on the wrench for leverage.

 

It's almost impossible when the car is jacked up on jack stands.

The main problem here is the rubber mounts that hold the assembly in place, any leverage that I apply to damper is just lost when the rubber mounts flex.

 

Use a adjustable wrench on the valve body/bracket to counter the torque and keep it stationary. It wouldn't hurt let some WD40 soak in over night.

 

Excellent, thanks. The valve body looked to be made of aluminum so I didn't want to press it too hard.

 

try to spend as much time as you can bleeding the system or you may end up with a hissing noise. In the end you will be happy you did the repair, you should feel a positive difference with high speed handling.

 

Yes sir, I was planning on running a full program of the rodeo (I think it's 15 minutes?) after all is sad and done.

One question - since you seem to be the pulsation damper connoisseur. You mention releasing pressure from the struts by using the bleed screws for each strut. Why is this necessary if the car is off and the valve blocks have the check valves closed?

I figured once the ABC pressure sensor is reading 0 bar, all pressure is relieved and the excess is in the tank. Since the sensor is on the valve body I figured this is the pressure reading inside the pulsation damper.

 

I don't have the tsb/repair info in front of me so I may be wrong. If I remember correctly you have to bleed the system via the bleed screws to get rid of the air in the system from the repair or that air will end up getting trapped in the system once you run the car hence the hissing sound, once the air gets trapped in the system it is hard to remove.

 

I did this fix to my S55 just a few months ago. I had someone hold the unit when removing the cylinder itself but it wasn't that bad especially since I only raised the car up a few inches anyways. I lifted the car just enough to get the wheels off the ground and supported it with jack stands. Then I lifted each wheel up until it just started to not hang and blocked it and lowered again to basically get a zero pressure situation. I did this so it wouldn't push out any fluid or suck in any air. It worked great when I pulled the old unit off I only lost a small amount of fluid and I just put on the new one. Dropped the car back down and filled up the tank since I did lose fluid in the part itself that had popped. Started it up hit the up down button a few times and I was done.
Now I am fixing the stupid shifter stuck in park problem. It is cold here in Maine.
Good luck
Johan

 

Thanks everyone for the help, here's my story:

The rough ride was caused by the damper.

After the change, the car handles like brand new. So firm and responsive. The rough ride is completely gone.

It was very difficult to do it on jack stands so I found myself a lift and had it off in 2 minutes.

YOU DO NOT NEED TO BLEED/RELIEVE PRESSURE IN THE LINES GOING TO THE STRUTS!

Let the car sit for about 10 minutes to make sure all pressure is out, lift it and undo the old pulsation damper with a 24mm wrench while holding the valve body with an adjustable wrench.

When you install the new damper, YOU MUST LEAVE the plastic shimmy tube inside, do not discard!

When done, verify fluid level in ABC tank and start the car. Perform the rodeo or about 5 minutes worth of up/down exerciser. Verify there are few to no bubbles on the ABC dipstick and you're good to go!

Here's the culprit:

Attachment 449196

and the new damper:

Attachment 449197

 

What makes you sure about not having to remove the pressure from the struts by bleeding the system?

 

Because just about everyone has done it like that, including myself. And iv done this on 3 separate occasions now.

 

Does the suspension have to be relieved of pressure? As in can this type of lift be used or should it be this type?

 

Relieve the pressure in the system but raising the wheels off the floor so they are hanging in mid-air for about 20-30 mins.

Like the ramp in your second link.

 

And then it really is as easy as unscrewing and re-screwing the part?

 

Well thats the basic principle behind it yes, but its not necessarily "easy" though, especially the unscrewing.

Get yourself 2 pairs of pipe wrenchs/mole grips and grab the ball with one wrench, and the body its screwed onto with the other wrench.

The tricky part is that your trying to unscrew the ball, but at the same time keep the rest of as still as possible because the its pretty easy to break a pipe.

You'll see what needs to be done when your under there. Maybe get a helper, i did.

 

My main concern is introducing air or debris or air into the system.

 

From the old unit being un-screwed off to the new unit being screwed on takes less than 3 seconds with 2 people there, if the second person is ready in place with the new unit in hand.

Virtually no chance of any debris or air getting into the system.

But after you've put the new one on i suggest you start the car and raise and lower the suspension fully about 30 times. Thats about the equivalent of a Rodeo test and it'l clear any problems.

Trust me, its not as hard or as scary as you might think.

 

True. It's a simple task. Just do it (carefully). Not a lot of air will enter, and it will not go out to the wheels while the system is off.

Raise the whole car to let wheels dangle, wait 15 minutes (put jack stands under for safety), pressure in system will reduce to where you can unscrew the ball. Wear goggles, as some fluid may still squirt out under remaining pressure, but probably not more than a tablespoon full. Install new one. Voila.

All four shocks use system pressure to hold up the car. I recommend you lift and block the whole car when you begin this repair at the front of the car. Even though the rears shocks have check valves in the rear valve body designed to help keep thempressurized when the car is turned off, you cannot be 100% sure the valve body at the rear will hold pressure if the weight of the car is still on the rear wheels. If you were to have leaky O-Rings or gunk in the rear valve body, it could allow a shock to compress in the rear when you open the system in the front. It is like the safety jack stand argument; do you trust a hydraulic jack's valve to hold pressure while you crawl under your car, or should you use jack stands?

There are several good posts that mention bleeding after the accumulators are replaced. You can find a bleed nipple for the ABC line in each wheel well. You don't want to open those when the wheels are dangling, but you also don't want to open them while the full weight of the car is pushing down on that wheel (unless you want to chop your arm off at the elbow.). You CAN put another hydraulic jack under a dangling wheel, raise it slightly to put the fluid under compression and open the bleed screw a bit to let some fluid/air out and then close it up. Most likely you will get a little inky black fluid only.

And remember when you are all done that you can't just drop the car down fast off the jack stands/lift. You have to bring it down gently because you have depressurization the system and it may go to the bump stops. (Probably not, but just to be safe...)You do not want damage the shocks by dropping the car fast. Once the wheels are back on the ground, start the car and ABC system will re pressurize and it will rise up again. You will probably get some ABC warnings until after a few up/down presses. And maybe turn car on /off a couple times. But mine always resets and I haven't needed a Star Diag system to do any of this type of work yet.

 

It was not necessary.