driveability

I finely got time to bring my 65 home after it blew an ABC line. Mine blew the line that holds the what I assume feeds a pressure relief valve. The line popped out of the coupler and the line otherwise looked fine. From what I have read lines blow off mainly due to 1 old rotten lines or 2 skewed accumulators does that sound reasonable ? I removed the accumulator and once again assumed it should house a diaphragm backed by gas. Another assumption is if i push on the diaphragm it should be hard to move, I did by placing it in a clamp and using a short steel rod draw them together. The diaphragm moved a bit but it took a lot of pressure in doing so. Has anyone seen a bad diaphragm ? or know of a way to investigate this issue ? I don't mind and will buy a new accumulator, just knowing the cause of the problem would be nice.

alx

i am not sure anybody here can provide you with a sensible answer about how much resistance there should be in the accumulator diaphragm.

oh wait- i have one - please do not poke the accumulator with anything...

on a related note some people are firm believers that the accumulators need to be replaced every so often as they act as a dampers and when they give up the abc is subjected to harsh pressure jolts.

how do you test an accumulator? i have no idea.

dtohio

Hydraulic accumulators are usually pre charged to around 1/2 system pressure, in your case if I remember the system is 200 bar (3000 psi) so expect half that for bladder pre charge. Pokeing the bladder to verify charge could be dangerous. I've charged commercial accumulators, there are kits made for this that will read and charge them. Bladders will lose some charge over time even if good like tires. If you can find out the mercedes pre charge pressure my gess is you may find a local hyd. shop that will set it, assumeing its not a sealed set up. I hope this helps.

driveability

That's some good information I thank you for not being condescending which is far easier and ( I find it sometimes tempting as well). I am going to replace both units since there one of the few parts which are reasonably inexpensive. I am in the process of getting a scanner which will let me see inside. Maxims is one of the units I am looking at, anyone have input (maybe another thread). I am a long time tune up and driveability specialist,(maybe why I look for details) started just when carburetors were in there last year (approx. 1984) so I have lived computer controls as it relates to cars. That's one of the reasons I bought this car and just maybe the ridiculous power LOL Well OK the power !!!!!!!!!!!!!!!!!!!!!!
Thanks John St John

driveability

They don't make it easy to replace this ABC line. The one from the pump to the hose that goes nowhere. the one with the "U' turn under the crank balancer. My fingers are angry ! I had to lift the engine a bit and just slowly go to work. I am looking for a scanner that can interface the system. I miss driving my car but got to take my time. Just an up date. will have some pictures coming for others to use.
P.s. its interesting how MB built this car, god knows without a computer it wouldn't be possible. What with the plastic covering the rear suspension parts ? Air control at high speed ? Nicely built however.

driveability

Back on the road again ! Didn't have any problems however the parts are not easy to replace. I was surprised ( over-joyed !) the system once I poured the fluid in came right back on line with no air issues to speak of. I'm sure doing it a second time (no not my car) would be much easier. The tool configuration / set up is now known. Trying to reach some of the fasteners is a real challenge. Getting the two lines back on the pump is stressful. Cross-threading that would be easy and expensive. Working in that tight space makes it a real challenge to keep things clean. I would recommend taking pictures of each step because the hard lines and soft lines are easy to forget there correct position and can be put on (almost) incorrectly. I hope I don't have to do it again !!!!

Here is the line that blew off




Here is a shot of the front accumulator



My lift and the big jack stands I made to stay alive !!!

alx

180-200 psi is tops. the system usually maintains around 140 and anything below 120 is considered insufficient. this is according to xentry.

maybe investigate who the manufacturer of the accumulators is and give them a call? merc suppliers are notoriously non-cooperative, but it might be worth a try.

cjcalo

Where at in California are you and would you care to do another?

driveability

I am in Orange County, another what ?

dtohio

You have mixed psi and bar; the system uses a hi pressure piston pump at 200 BAR which is 2900+ psi to serve the ABC.

XZACM102

Did anyone replace accumulators just as preventative measure to avoid ABC issues ?
I heard that this is something that should be done every couple years. How many accumulators are there and what is the estimated cost ?
Any thoughts ?

alx

Yes. 200 bar. 1 bar is 14.7 psi. Brain fart on my side.

red60R

what do the accumulators cost?

Petej

Anybody?

OCKlasse

I believe there are around five accumulators...they're around $120 each from oediscountparts.

XZACM102

My service B is approaching so I've decided to replace ABC accumulators as a part of preventative maintenance.

Can anyone who has done this advice what needs to be replaced ?

I can buy front accumulator no.31 and rear 32 as shown in the diagram for $150 each.

Are there more ? I believe these 2 are both part of the rear suspension

OCKlasse

So, there's one on the pressure relief (number 18 on your diagram), one on the front valve block (31), and another on the rear valve block (32). That's from memory...

XZACM102

Thanks. When I search for MB parts I can get both front -31 and rear- 32 accumulators for $150 each but 18 - relief valve costs almost $1000. Is that correct ? It seems like the accumulator is part of the valve and is not sold seperately......

alx

the pressure relieve and accumulator are two pieces

accumulator - 2203270215

pressure relieve valve - 2203200858 (it comes with accumulator)

so if you want to replace the accumulator only - you order 2203270215

if you want to replace the valve - you order 2203200858 which comes with a valve.

Crissus

Have all of them the same part Number? "2203270215" ???

OCKlasse

No. That's the pulsation damper accumulator part number.

Crissus

Right i just checked EPC. Its actually 4 of them in the car.
Which ones go bad? I guess all? Under the car i saw that one of them (pretty near to the rear right wheel) is even covered in rust from outside. Abaout to change ASAP i believe.

Pics:


#190 (needed 2) have Part-Nr: 220 327 01 15 and is called "Air reservoir"
#185 (needed 1) have Part-Nr: 220 327 04 15 and is called "Air cell
#410 (needed 1) have Part-Nr: 220 327 02 15 and is called "Pressure accumulator "

Switta

ah darn i had my rear block on the bench with #185 loose and could have replaced it then o well things are working fine so i guess i will wait on that one . i replaced the one above rear diff and the pressure valve one and today i am rebuilding my front valve block and replacing that one .

good to have the part # though thanks for posting it .

Dave

PB617

Dropped off my CL off this morning to have my indy change the ABC filter and do a rodeo and change the filter again. I was wondering if i needed to change the accumulators also...i sometimes feel it should be smoother over bumps. The car only has 33k miles but i'm sure the accumulators are original. What do you guys think?

tusabes

there are 4