Dreaded 'ABC Drive Carefully' warning came on...

SL63 Mark

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What’s an accumulator? I did not even know we had those. Deep joy. Are they cheaper than the pump to fix ? How many are there .
 
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rexemper

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What’s an accumulator? I did not even know we had those. Deep joy. Are they cheaper than the pump to fix ? How many are there .

There are 4 in all. 2 main ones and a return and a damper which are smaller - at least that is how I understand it from the 'ABC - How it all works' sticky.

Cheaper individually than a pump but if you need to replace all 4 then there may not be much in it. Good news is that you can replace them one at a time as they go.

What do they do? - From the sticky - "They are black spheres that contain nitrogen gas (air) trapped behind a rubber membrane. Hydraulic fluid is allowed to travel in and out of the sphere based on the pressure differential between the rest of the system and the air on the other side of the membrane. The compressed air in the accumulator pushes back against the fluid and can either absorb pressure or supply pressure."
 

Submariner1

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Quick update - the guys at Star diagnosed it as blown/worn accumulator, especially as there was a slight vibration in the car which went when the RPM climbed and the pump took over some of the work (so I understand). The error codes came back as low pressure, but there were no visible oil leaks to account for the loss of fluid.

Booked in for next week to fix....

Sounds logical, the nitrogen ball membrane gives way, and so swallows some ABC fluid.
Hence you see a drop, and once topped up doesnt drop any more.

Just a thought if they are changing a ball, is it a good time to have the fluid flushed and a new filter to prevent future dramas?

When was you fluid changed ?
 

Submariner1

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Change them all! Blown accumulators cause blown lines as the shock waves do not get absorbed, mainly on the return and pulsation damper.

Sound advice, some of those lines are expensive and on mine , one big one £228 was “sweating”.
Note: not leaking, zero fluid loss. Just tiny beads of fluid coming through it.
Lots of labour time think £300. TBH how they got that line out is beyond me! Must have been a horrible job.
I got my main dealer to check it had been done properly, as if it splits they said you will lose all pressure instantly and almost definitely need a new pump.

Maybe it was a waste of money .... i.e. too over cautious. But imo if the rubber hose part lets any fluid through it ... there must be a good chance it will just split completely?
So if Alex says bad accumulators can wreck these lines .... I wouldI do what he says.
There are quite a few lines in my car and I assume same in SLs.

OK I admit it, not having warranty ABC issues scare me ;). ( one new front strut ).
My pump is 188 Bar if memory serves me well, anyway they said that was good? Not sure what a new one is?
Anyway I had my fluid and filter changed at 40K even though the fluid was very clean.
Personally I would change mine at 20K given the chance.

OK my fluid was clear and a light green with just a few micro black dots of crap, so maybe MB are right and it doesnt need changing. But I have seen videos where it was realy filthy! High mileage, worn pump who knows .... but for a while MB said some gearbox’s oil didn't need changing!! And they changed their mind in that one!
 
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rexemper

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Sounds logical, the nitrogen ball membrane gives way, and so swallows some ABC fluid.
Hence you see a drop, and once topped up doesnt drop any more.

Just a thought if they are changing a ball, is it a good time to have the fluid flushed and a new filter to prevent future dramas?

When was you fluid changed ?

As per previous post, I'll probably get the fluid and filter changed at the same time as not sure when it was last done. It is a pretty clean green colour though as opposed to brown or darker.
 

mrmb

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188bar is really good for this pump and I wouldn't worry too much. Me and my dad we are doing an ABC oil change every year, using Pentosin oil. We have some work on the system ourselves including - taking out ABC Pump and replacing the cover. We thought we will have to change a pump as there was a leak but in USA we found an aluminium covers that are made for this pumps in a rebuild kits including all the gaskets etc. 3 years since the job and no sign of any leak. We have also replaced every possible rubber hose, made for us in one of hydraulic specialists in our area. ABC system is a bit feaneky, can cost a lot to fix it however for any problem a proper diagnosis should be made first on SD. Do not let any dumb mechanic to do any work on this system if he has no experience with it. You have to be careful with few things and it is really easy to break some of them. I am not an expert in this system but as I have done quiet a bit of work on it with my dad, and read hundreds of pages about it including WIS documentation I will be happy to help you if you will have any problems with it :)
 

LostKiwi

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ABC operates at between 150 to 200bar from what I recall. Our car also operates at 188 bar so I'm happy with that - especially for a 16 year old car.
I've read up loads about ABC and in my view the big thing with ABC is not to think about it. Putting aside a contingency fund is an excellent idea as is doing preventative maintenance as part of services (alternate ATF and ABC every 20k for example).
Apart from that just get out and drive it and don't worry that around the next corner it will fail as 99.999999% of the time it won't.
 

SL63 Mark

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Agree with Alistair. Mine has been trouble free for 6 years, the one time it went wrong it was easy enough to sort out. The ABC system is actually extremely well made, if you look closely at the pipes and hoses in hidden areas of the car, they are well over engineered. MB did not do things on the cheap.
 

Submariner1

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ABC operates at between 150 to 200bar from what I recall. Our car also operates at 188 bar so I'm happy with that - especially for a 16 year old car.
I've read up loads about ABC and in my view the big thing with ABC is not to think about it. Putting aside a contingency fund is an excellent idea as is doing preventative maintenance as part of services (alternate ATF and ABC every 20k for example).
Apart from that just get out and drive it and don't worry that around the next corner it will fail as 99.999999% of the time it won't.

Very wise advice.
Especially the dont worry part.
It also helps knowing an excellent Indy like MBS ... those guys really know their stuff and are very reasonable. They make ABC manageable.
Main Dealer prices are exceedingly uncomfortable.

I only think about it when I have some Chav up my arse, on a windy road.
Dont you just love it, when you come up to a tight roundabout, and don’t touch the brakes, just gently put the power on before exit!

Flick a glance in the rear mirror and watch him struggle ;);) and then suddenly he’s 30 meter further behind you. :):)
Probably dumbstruck how this old barge glided around that with absolutely no drama ... no fuss! :):):)

He he he F1 Race technology mate!
Or as Clint would say ... “built like no other car” as he exited the multistorey! For those old enough to remember the movie :):)
 
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