Glad to hear! Did you have to bleed the system after?

No, I didn't bleed. Just lowered and raised the car a bunch of times and then checked oil level.

Hmm that's awesome!

So far so good. Everything seems to be working well with the ABC system. No leaks from the replacement pulsation damper either. If you're thinking of doing this, you really should get a proper 24mm box wrench and a small pipe wrench. With those two tools and a pair of jack stands, it shouldn't take more than 5-10 minutes to complete.

Mine was replaced by the dealer when I bought the car.. I thought he said it was on the rear passenger side but maybe I was mistaken because that was the side the strut was replaced. By he specifically said he replaced the one that causes the light to come on when you hit a bump.

Probably one of the ABC accumulators then.

I had the same humming/hissing noise inside the car. Before I read this thread I would have sworn that it had to be the transmission, because it was changing with the revs. It sounded worst around 1,500-2,000 rpm.

After changing the pulsation damper it's completely silent now. Thank you very much guys! I can't even tell if the enginge is running when stopping at a red light .

I'm not only writing this to thank the guys who shared their wisdom and experience but to give everyone who is playing with the thought of doing it themself the last push. Believe me, this is dead easy and absolutely worth it!
Even if it wouldn't cure it completely, it's never wrong to change a wear item.

The only similar sound I hear is for a few seconds when starting the engine. When I put it in D it silents immediately, so no big fuss to me.

You've convinced me to do it! Do I just ask for the pulsation dampener? Thanks guys!

Yeah I read the invoice and it looks like they did two accumulators.. the pulsation dampener on the front passenger side looks like it's not so new to me.

This is the part number: A 220 327 02 15

I paid under $150 for it on eBay.

Thanks!

The manual states you do not need to bleed. just let the car sit for approx 10-15 minutes for pressure to bleed of from the pump.

Hello Gents! I’d like to thank you all for your expertise as I would have changed my PS pump but with the recent buzzing noise. In reading your posts, I assume that the cause comes from the front Accumulator / Damper. The only problem I have is I can’t find anyone selling it or can’t find a compatible part to replace it! I got the original part number from the front accumulator which is P/N: 020-4315-043-611/80. I also tried to remove it so I can see if a chopstick bottoms out but I was unable to remove it, I guess I will go buy a heavy duty strap removal tool. Can anyone help find an available / compatible part online? I’m hoping it’s not my pulsation damper that is located on top of the PS pump as that seems hard to replace but I can’t find that part either online P/N: 22032012721112061250. Any/all replies are greatly appreciated and thank you again for your help & expertise!

Situation: Constant buzzing noise after going over first speed bump and noise raises with the engines RPM. Noise is most noticeable from idle to 2000 RPM. No hydraulic leaks from the PS reservoir nor the ABC hydraulic block. See pics via PDF. I hope I an naming the parts correctly! Please let me know if you have any questions as well!

2001 S55 AMG 5.5L V8 w/ ABS System. VIN# WDBNG73J31A187663

Cheers! Nelson