Uprated ABC Pump in a W220?

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W4SIM

Banned
Joined
Jan 26, 2011
Messages
216
Car
S55 AMG Kompressor
Iv been looking at a 2004 S55 recently that i want to buy and one of the first things i asked the chap over the phone was about the suspension.

Glad to hear he was a Merc enthusiast and knew what he was actually driving as opposed to someone who just jumps in to get from A to B.

Anyways, he knew about the whole suspension issues with these cars and he told me that about 3 years ago the ABC pump did indeed fail on the car and was replaced with an "updated" pump.

I didnt know there was such a pump. So how true is it? Did Mercedes make some revisions to these pumps to make them better?

Thanks.
 
yes, there is a new part number on most of the abc system, as when i got new struts valve block you could order either part number, i went with the later ones.
 
yes, there is a new part number on most of the abc system, as when i got new struts valve block you could order either part number, i went with the later ones.

Thank you very much, thats great news :bannana:

So hopefully that should make the ABC Pump atleast that bit more faithful. The struts and valves on the other hand, well . . . . . . :confused:
 
the abc pump normally fails as a result of having to work too hard. The thing with the ABC is that no component is particularly that bad, its the fact that when one goes it knackers another. ie pump goes it takes out a valve block, or a strut goes takes out the pump and valve block. Or a valve block goes it takes out a strut as its not supplying enough oil. Thats how you get the ridiculious abc bills.
strut knackered, 1k takes out pump and block 3k.
 
the abc pump normally fails as a result of having to work too hard. The thing with the ABC is that no component is particularly that bad, its the fact that when one goes it knackers another. ie pump goes it takes out a valve block, or a strut goes takes out the pump and valve block. Or a valve block goes it takes out a strut as its not supplying enough oil. Thats how you get the ridiculious abc bills.
strut knackered, 1k takes out pump and block 3k.

Yeah i see what you mean, usually you do see more than one component let go at the same time, i guess its a kind of a chain. One lets go, takes something out along with it.

But isnt there a bit in the middle somewhere that acts like a damper system for the whole ABC system if it takes a violent bump somewhere??? Iv read about it somewhere on the US forums whereby it takes a certain amount of the shock, but in time it tends to seize and fail. Then when a big shock goes through the ABC system it goes all the way from the strut back to the pump, do that a couple of times and it'll take out the weakest link in the chain, usually a pipe/joint somewhere. Its supposed to be a serviceable part, but not a lot of people even know about it.
 
W4SIM said:
Yeah i see what you mean, usually you do see more than one component let go at the same time, i guess its a kind of a chain. One lets go, takes something out along with it.

But isnt there a bit in the middle somewhere that acts like a damper system for the whole ABC system if it takes a violent bump somewhere??? Iv read about it somewhere on the US forums whereby it takes a certain amount of the shock, but in time it tends to seize and fail. Then when a big shock goes through the ABC system it goes all the way from the strut back to the pump, do that a couple of times and it'll take out the weakest link in the chain, usually a pipe/joint somewhere. Its supposed to be a serviceable part, but not a lot of people even know about it.

You are referring to a pulsation damper. Unfortunately this is the ONLY part of the ABC system that will NOT cause the system to fail or go into limp mode. The damper reduces the vibration of the fluid coming directly from the pump main line. It does nothing but reduce vibrations. The damper has a nitrogen chamber inside it. Just to put your mind at rest, there is no 100% ABC safe car. Even brand new cars have failures. HTH
 
W4SIM said:
Yeah i see what you mean, usually you do see more than one component let go at the same time, i guess its a kind of a chain. One lets go, takes something out along with it.

But isnt there a bit in the middle somewhere that acts like a damper system for the whole ABC system if it takes a violent bump somewhere??? Iv read about it somewhere on the US forums whereby it takes a certain amount of the shock, but in time it tends to seize and fail. Then when a big shock goes through the ABC system it goes all the way from the strut back to the pump, do that a couple of times and it'll take out the weakest link in the chain, usually a pipe/joint somewhere. Its supposed to be a serviceable part, but not a lot of people even know about it.

W4SIM said:
Yeah i see what you mean, usually you do see more than one component let go at the same time, i guess its a kind of a chain. One lets go, takes something out along with it.

But isnt there a bit in the middle somewhere that acts like a damper system for the whole ABC system if it takes a violent bump somewhere??? Iv read about it somewhere on the US forums whereby it takes a certain amount of the shock, but in time it tends to seize and fail. Then when a big shock goes through the ABC system it goes all the way from the strut back to the pump, do that a couple of times and it'll take out the weakest link in the chain, usually a pipe/joint somewhere. Its supposed to be a serviceable part, but not a lot of people even know about it.

You are referring to a pulsation damper. Unfortunately this is the ONLY part of the ABC system that will NOT cause the system to fail or go into limp mode. The damper reduces the vibration of the fluid coming directly from the pump main line. It does nothing but reduce vibrations. The damper has a nitrogen chamber inside it. Just to put your mind at rest, there is no 100% ABC safe car. Even brand new cars have failures. HTH
 
The ABC pump is a pulse generator pump. The hydraulic system is constantly (few times a second) pulsed with hydraulic oil which is directed to each corner of the car by two control valves (front and back) and a control unit on each shock. The damper unit keeps the system under constant pressure.

The "new" pump is only a re-numbered "old" pump. From 2004/05 onwards Mercedes seem to have re-numbered the same units for some reason (unknown to me):dk:

Mel.
 
You are referring to a pulsation damper.

Indeed that is it. I wasnt exactly sure of what it did but now having read your post i see what it does. I honestly thought it does more than that but i suppose anything that helps reduce the burden on the ABC system must be a good thing. I read about it a good few months ago and the guy was saying how this can be overlooked part that keeps causing various problems with the suspension. I think he replaced 2 struts, a valve, a split pipe and a pump within the space of a couple of months before replacing the pulsation damper and finally got it sorted. But in all that time no one at Mercedes mentioned this to him. :wallbash:



Unfortunately this is the ONLY part of the ABC system that will NOT cause the system to fail or go into limp mode.

Your kinda saying it like thats a bad thing, or am i reading it wrong? :rolleyes:
 
Just to put your mind at rest, there is no 100% ABC safe car.

Er, Thanks . . . . that'll make me sleep easier tonight! :crazy:

But i know what you mean, sometimes its just pot luck. ;)
 
The "new" pump is only a re-numbered "old" pump. From 2004/05 onwards Mercedes seem to have re-numbered the same units for some reason (unknown to me):dk:

So what your saying is that its the same problem but in a new box??? :eek:

Damn You Mercedes :mad:
 
Have changed a few pulsation dampers over the years on ABC systems, usual clue is increased noise in the system.

They are just an accumulator in the main fluid feed from the pump, and easy enough to swap.
 
Have changed a few pulsation dampers over the years on ABC systems, usual clue is increased noise in the system.

They are just an accumulator in the main fluid feed from the pump, and easy enough to swap.

Thanks, the guy did say to change it at about 40-50k. Cant remember wether that was part of one of the big services or wether he recommended having it changed at these intervals just to be on the safe side.
 
My rear passenger side shock seems to be making a knocking noise over bumps, there are no abc warning lights and the abc works perfectly, could this damper be my problem?!
 
More likely one of the ball joints, the ones in the upper wishbone can make quite a racket.
 
My rear passenger side shock seems to be making a knocking noise over bumps, there are no abc warning lights and the abc works perfectly, could this damper be my problem?!

As said above, if its usually making a knocking noise over bumps then its usually a ball joint or bush related problem.
 
can this be DIY'd? im pretty capable, any walkthroughs on the net anywhere?
Cheers....
 
from all ive read and learnt about abc. Also having spoken many times to arnolt industries in us. The struts main problem is the rubber at the top. Its how can we put it. Rubbish. Also you cant purchase it seperately.
I am guessing your rubber has gone which gives symptons of ball joints. Same happened on my front struts.
The miss you getting is the excessive force the stut is having to do now the rubbers at the top are not doing there job. dont know when, but it will happen the strut will fail and crap will run around the system blocking and knackering a valve block or pump.
Get it looked at. Arnolt industries sell reconditions shocks price of 2 is same cost as one from stealers.
 

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