Date registered: Dec 2002
Vehicle: 2003 SL55 Obsidian Black, 2007 ML500 Silver
Mentioned: 0 Post(s)
Quoted: 3 Post(s)
ABC: Change the front and rear pressure reservoirs
After replacing the ABC pump on my 2003 SL55 (134,000km) a few months ago I kept getting intermittent white ABC warnings, particularly after going around a corner with a bump slowly or after hard acceleration. For a while now the ride has seemed a bit hard and not like the magic carpet it used to be.
I decided to replace the pressure reservoirs. The best local price was $584 each (I didn't bother asking the dealer) The cheapest price was on parts.com but they don't ship to Australia. I ended up buying two from pelicanparts.com for $580 shipped
The reservoirs are located in front of the front and rear wheel behind the plastic wheelarch shrouds.
The procedure is sort of similar for both ends, I started at the back.
Chock the wheels, handbrake on, jack up the car and use a secondary support
Remove numerous plastic clips and nuts that secure the wheel arch shroud and gently pry it out... it's tricky
While holding a tin under the bleed screw crack it and you will collect about 150ml of fluid
I was dismayed at just how black and opaque the fluid was after I had flushed it with 4 litres of fresh stuff about a year ago ( yes I know I should have used more; the manual says 10)
Remove the nut securing the assembly (indicated in the photo) and the pipe clamp (in another photo) and gently pull it out to the rear and down as far as the pipes and hoses will allow.
Loosen the pipe nut with a 17mm spanner then remove the three nuts securing the reservoir.
Undo and pull out the pipe being careful not to let any dirt enter and remove the reservoir
Assembly is just the reverse, getting the nut on the pipe clamp is tricky
The front starts out the same. Only remove the front wheel arch plastic shroud
Loosen the bleed screw and catch the fluid that comes out; about 100ml is all I got
The valve/ reservoir assembly does not appear to come out easily so you must undo the pipe nut first then remove the three nuts that hold the reservoir in place. The two outer ones are OK, the inner one will need an extension on your 1/4" drive socket and you will need to stick your head under to see the little devil
Assembly is just the reverse but the car will be very low when you lower the jack
I had only bought 4 litres of ABC oil, not intending to do a total flush.
I syphoned out all of the oil in the reservoir then filled it up with fresh stuff running a hose from the return line down into bottles so I could gauge how much was being used
When I started the car it took a while to lift and the fluid level dropped pretty smartly.
After it had run for a few minutes and I topped the fluid level up the returning fluid was transparent and looked clean.
Unfortunately I only had another litre of fluid left and one rodeo cycle went through that pretty smartly.
The oil in the reservoir is certainly much cleaner but I have ordered another 8 litres and a filter and will do the job properly
The ABC fluid in Australia is prohibitively expensive with the dealer charging $90 per litre and Silverstar spares wanting about $60
When I contacted MB spares in the ACT they quoted $30 something per litre and I questioned that they were supplying the right part. When it arrived it was SWAG brand Power Steering Fluid and their website lists it as the same specification as the original Pentosin
The removal and replacement of the reservoirs took about an hour each and you could probably do it in half that time if the trim wasn't so difficult to remove and replace
It was a straightforward job and the car rides beautifully again with no warnings