Cali600

2007 S600, 120k miles. Recently, my accumulator or pulsation damper? (connected to the tandem pump) split open causing complete loss of ABC fluid. I gained access to the unit and tried to remove it but it wouldn't budge. I then tried an oil filter strap wrench and it still wouldn't budge. Looking for any help on how to get this thing out. I do not see any hex heads, and I want to make sure that this thing is regular threaded and can be unscrewed. Is it possible that it is removed some other way? I have attached pictures of the units top and bottom and the crack along the side. Any help would be appreciated

Cracked unit

Top of unit

Bottom of unit

pillowshot

Er. That thing on the top of it is supposed to be a hex-nut. Looks like you either have an aftermarket unit or something really weird happened to it (overtightened?)

This is what mine looks like - original MB part:



It should not be that tight (I want to say 35nm but not 100 sure). It is normal threaded and can be unscrewed (turning it CCW).

Cali600

Thanks for the help. I think you're right, I'm guessing someone over tightened it and the hex popped off. I'm pretty sure it is an oem part based on the mb logo and correct part number. Never know with knockoffs these days though. I guess I'll get back in there with a bigger impact wrench and the oil filter strap and try and give it more power. Hopefully I can get this sucker out

DaleB

I believe you're right. It looks like that is a stud to which the hex part was probably welded, and it's popped off. The strap wrench, or if you can't get enough traction with that, a chain wrench should work. That's what we had to use on mine to get the front accumulator off (not the damper, that came out easily). Another option would be to tack weld a hex nut back onto that stud.

MBCO

I had similar problems getting my PD removed from my SL550. It was seized. I didn’t want to spray any anti seize chemicals there for fear of contamination of ABC fluid. I had the 17mm head on the PD. I used an extension on the 17mm socket and a big hammer and after a couple firm blows it loosened. In your case without the 17mm head you might be able to use a Dremel tool to cut a slot into the PD so that a straight blade screw driver fits. Another forum member used this method when his PD 17mm fitting became rounded. Good luck.

George993

I removed mine using Klein Grip-It S12H (12 inch) strap wrench. Quick and easy. (The wrench is made by a small privately owned company, so it's not even made in China but in USA)

DRTYLNDY

All 2007's have the same PD without the nut on top. I am in the same boat as you. I have tried a few times to remove it but still no luck. The idea of dremelling a slot in it for a large screwdriver
sounds interesting and I may just try that. Good luck
Johan

DaleB

Not all. My 2007 had the hex nut, as have a couple of others I’ve seen. So does the new replacement I installed. Maybe it’s not unusual for them to pop off, I don’t know.