When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Ok, I know on the W221 there are 3 (down one from the W220). So... I know one is under the hood, right on the pump and one is near the spare tire, in the back. But where is the third ABC accumulator/nitrogen sphere located? Bonus points if anyone can get me part #s for them!!
check inside the front driver side wheel liner (US). Usually when searching for these parts, I found the one attached to the pump is called a pulsation damper and the other two are called accumulators. Here's just one site that has the accumulators for front and rear. https://www.carpartsdiscount.com/act...html?3594=2973
check inside the front driver side wheel liner (US). Usually when searching for these parts, I found the one attached to the pump is called a pulsation damper and the other two are called accumulators. Here's just one site that has the accumulators for front and rear. https://www.carpartsdiscount.com/act...html?3594=2973
Yeah, I didn't buy the dampener for the pump... so, just ordered that and the rear accumulators. From what I've learned, all three of these are maintenance items and do wear out over time. They are all original on a 2007 with 93k so not a bad idea to do em all.
Anyone done this? Is it really just as simple as screw off the old, screw on the new? Yes, I know cleanliness is king, but other than that? Do it on a cold system to avoid spillage and need to bleed it, right?
I've only done the pulsation dampener so far and yes, do it cold, just screws off. I had to remove the air box on the driver side to access it. I think it is a good idea as maintenance, but I haven't done the others yet. I did not have to bleed the system after the pulsation dampener and my fluid level was stlll ok. If you do all 3, I'd consider flushing the fluid and new filter once done.
I've only done the pulsation dampener so far and yes, do it cold, just screws off. I had to remove the air box on the driver side to access it. I think it is a good idea as maintenance, but I haven't done the others yet. I did not have to bleed the system after the pulsation dampener and my fluid level was stlll ok. If you do all 3, I'd consider flushing the fluid and new filter once done.
I'll slap a new filter in, but the fluid is looking very green and fresh to me, so I think a full flush would be overkill at this time. I appreciate the "intel"
I'm chasing a rapping/tapping sound that happens upon deceleration at lower speeds. I suspect the fluid is depressurizing and crashing into that dampener that can't deal with it any more
it's a good place to start. That part seems to cause many different sounds that people have chased by replacing numerous other parts only to find out it was that pulsation dampener the whole time. Mine sounded like the pump was failing so I tried the dampener first and it cured the problem. good luck!
it's a good place to start. That part seems to cause many different sounds that people have chased by replacing numerous other parts only to find out it was that pulsation dampener the whole time. Mine sounded like the pump was failing so I tried the dampener first and it cured the problem. good luck!
Yeah, I'll sometimes get a 2003 clapped out Pontiac Grand Prix power steering whine too at lower speeds, especially after long highway driving. No errors, no leaks so I am hoping this knocks it out!
1. Replacing the pulsation dampener on the pump fixed my tapping noise 100%. It also reduced that "whine" at low speeds by 80%. So people... replace it. Took 10 min and it was not that expensive.
2. Replaced the rear accumulator, aka nitrogen sphere, in the rear. All three nuts holding it to the car are under, accessible by removing the spare tire well shield. Then remove the torx bit holding the high pressure line into the sphere. Then pry the high pressure fitting out. To replace, I found it easiest to have someone hold the sphere from above while I used rubber mallet to pound the high pressure fitting into the new sphere. I had originally thought the torx bit would "pull" the fitting in, but that's not the case, so don't try this! Now tighten the torx bit and the other 3 nuts and you're good to go. I did it cold and maybe spilled an ounce or two of fluid.
3. Front accumulator location though.... it most certainly was not behind the driver's fender well liner! Pulled that apart last night and it's not in there.
Probably will try passenger side and see what's there...
The W221 sphere is in the front, drivers side area behind the bumper. Drop the underbody trays and it's pretty clear, there it is. Attached to the valve block assembly (that metal looks shiny and new!). I had a REALLY hard time breaking mine loose. Ended up using a strap ratchet and a ton of force. The new one went on easy and once it was snug it really couldn't get any more tight.
great thanks for the photos! So the liner doesn't need to come out, just the bottom cover. Do you notice a difference in ride at all or do you think the old one was still good and you did this as preventative maintenance? I may do the same. My car is lowered very slightly, but when I hit bumps, the rear feels like it bottoms out. I think the accumulator may be bad in the rear, which doesn't give the hydraulic fluid a place to go when you hit a sudden bump. Did you have any of that before the swap?
great thanks for the photos! So the liner doesn't need to come out, just the bottom cover. Do you notice a difference in ride at all or do you think the old one was still good and you did this as preventative maintenance? I may do the same. My car is lowered very slightly, but when I hit bumps, the rear feels like it bottoms out. I think the accumulator may be bad in the rear, which doesn't give the hydraulic fluid a place to go when you hit a sudden bump. Did you have any of that before the swap?
1. Fender liner did not need to come out. That "flange" on the sphere itself is useless because it's like 26mm so any wrench that can fit that is too fat to fit in the space. Damn false advertising.
2. I can tell no difference. I'm a new owner of this car and did them both "just because" the car is 11 years old and considered it preventive maintenance
3. My car is slightly lowered too (via links) and I never noticed any bottom out issues. I believe if the sphere itself is bad, you'll get warning message on the display
4. From what I've read and learned, those spheres and the steering pulsation dampener are considered "wear items" which makes sense to me.
5. I DID notice dramatic improvement (reduction) in weird noises up front upon replacement of the steering dampener
1. Fender liner did not need to come out. That "flange" on the sphere itself is useless because it's like 26mm so any wrench that can fit that is too fat to fit in the space. Damn false advertising.
2. I can tell no difference. I'm a new owner of this car and did them both "just because" the car is 11 years old and considered it preventive maintenance
3. My car is slightly lowered too (via links) and I never noticed any bottom out issues. I believe if the sphere itself is bad, you'll get warning message on the display
4. From what I've read and learned, those spheres and the steering pulsation dampener are considered "wear items" which makes sense to me.
5. I DID notice dramatic improvement (reduction) in weird noises up front upon replacement of the steering dampener
Nice explanation of how to get to that front accumulator. I have an active post because a few days ago I got a loud POP front the front and it seems to be this accumulator.
Tell me, is it absolutely necessary to jack the car up off all 4 tires?
Also, did you do anything to prevent a dramatic loss of pentosin?
Nice explanation of how to get to that front accumulator. I have an active post because a few days ago I got a loud POP front the front and it seems to be this accumulator.
Tell me, is it absolutely necessary to jack the car up off all 4 tires?
Also, did you do anything to prevent a dramatic loss of pentosin?
Thanks
I don't see any reason that you can't do this with just one tire in the air (use jack stand!). When I took the sphere off, the pentosin kind of just trickled out. I bet I spilled less than a cup in total with a quick swap of the old for the new. It didn't come gushing out (make sure you are working on a cool car and the cap on the reservoir is cracked).
I don't see any reason that you can't do this with just one tire in the air (use jack stand!). When I took the sphere off, the pentosin kind of just trickled out. I bet I spilled less than a cup in total with a quick swap of the old for the new. It didn't come gushing out (make sure you are working on a cool car and the cap on the reservoir is cracked).
Good luck!
Thanks so much for the timely reply. Yea I just can’t see paying $1,600 for a job that seems so straightforward.
I have ramps so the tires will still be holding the weight of the car while I’m removing. Do you think jack stands would be better so there’s no weight on that front drivers side tire?
I don’t want to have 200psi of pressure coming at me because the tire is still holding the weight on the ramp.
good point... not sure what will happen. Every time I worked on my car I had it 100% up in the air. I'd be ready to swap it fast! Keep in mind, it's a closed system, so weight on any wheel will "push" the fluid around
good point... not sure what will happen. Every time I worked on my car I had it 100% up in the air. I'd be ready to swap it fast! Keep in mind, it's a closed system, so weight on any wheel will "push" the fluid around
Right! That’s what I thought. I think it would be wise to just use jacks and get it off the ground 100% just to be extra safe.
The reason I even considered it is because I know for a fact the ABC reservoir isn’t pressurized like the coolant reservoir since when the accumulator failed the pentosin it held simply came out via the dip stick cap as an overflow fail safe.
I appreciate your insight so much!
One last thing, when you decided to use the strap wrench (I have a rubber one I use to remove the oil filter) did you need to support the valve block in anyway? Or did you just go at it with brute force?
use your judgement on supporting the valve block. If that accumulator is really on there, then you might need to put a hand on the block as it does move a little bit. But for mine, we were able to just crank on the strap
use your judgement on supporting the valve block. If that accumulator is really on there, then you might need to put a hand on the block as it does move a little bit. But for mine, we were able to just crank on the strap
Good deal! I appreciate you so much. Have a great weekend.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
