DIY to remove and install ABC pump

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spawnywhippet

New Member
Joined
Feb 1, 2016
Messages
4
Car
2003 R230 SL500 Designo Edition
I am writing this DIY as I don’t find the instructions in WIS to be very informative. It describes how I replaced my own ABC pump after my local dealer wanted to charge over $8k for the job, due to an occasional red ABC Drive Carefully warning on my dashboard, and me needing to re-prime my pump every few hundred miles. I am happy to modify this DIY with feedback or other advice. This work is done at your own risk, I take no responsibility for you skinning your knuckles, damaging your car or anything else by using these instructions!
Total time taken to remove and reinstall the pump was about 5 hours and 2 beers, including taking pics and notes. I spent another hour or so filling and bleeding the ABC and power steering. The pump was a remanufactured unit I bought off ebay for $400. Banjo O-rings were cleaned up and reused, as apparently they cannot be replaced.

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Tools needed

Sockets
8mm (for undertrays)
10mm deep socket
17mm (and long breaker bar for belt tensioner)
19mm
E10 torx
E12 torx
Short and long handled ratchets
Torque wrench

Wrenches
17mm flare wrench
19mm flare wrench
19mm box wrench / ring spanner

Other tools
Hose clamp pliers
Hose crimping clamps to reduce fluid leakage
Flat head screwdriver
Jack stands
Jack
Lots of shop towel / rags to clean up spillages
Drain buckets
Some way to apply a little air pressure to the reservoir after reassembly to prime the tandem pump (I use an air compressor with a rubber bung with a hole through the center)

Consumables
10 litres of Pentosin CHF11S for ABC system (bought from Amazon)
ABC reservoir filter 0031846101 (bought from Amazon)
Plastic hose seals or caps, or kitchen wrap and rubber bands to temporarily seal off hoses etc to prevent contaminating the system with dirt.


Step 1
Remove the engine trim plastics and filter intake hoses. WIS says to remove the fan shroud but this is not necessary. (I was unable to get mine out through the gap without removing coolant hoses, and discovered it didn’t need to be removed anyway.)
Remove the front center 2 undertrays from beneath the engine at this time, using an 8mm socket. Try to clean all the areas thoroughly with degreaser where you are working to reduce the risk of getting contaminants into the ABC or power steering system.

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Step 2
Loosen (do not remove yet) the 3 e-torx bolts holding the pulley to the ABC pump, then remove the serpentine belt. To remove the belt, put a 17mm socket on the belt tensioner, release the tension by turning the bolt to the left and slide the belt off the pulleys. Make sure you review the diagram (see lower down the page) of the belt routing before you do this so you are clear how it goes back on. Leave the breaker bar on the tensioner, as you need to move the tensioner pulley aside again to remove one of the ABC pump etorx bolts. Inspect the belt for cracks or wear and replace if necessary.
Now remove the 3 ABC pulley etorx bolts and remove the pulley from the ABC pump.

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Step 3
Siphon, pump or syringe out the fluid from the ABC and power steering reservoirs using very clean equipment. Do not let any contaminants get into either tank.

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Step 4
Put drip trays under the car to catch dripping hydraulic fluid.
Remove the hose clamps from both of the hoses on the ABC pump, then remove the hoses. I used crimping tools to try and reduce the fluid spilling in the engine bay, but I still lost a fair amount. Cap and seal all hoses as you remove them, I used kitchen wrap and some plastic caps I had in my workshop.

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Loosen the hose clamps from the 2 hoses where they go to the power steering reservoir and ABC reservoir, then pull the hoses from them.

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Step 5
Remove the front 2 of the three 10mm bolts holding the reservoir assembly in the car, then loosen the 3rd nut that attaches the bracket to the strut tower. This nut doesn't need to be removed entirely. Then remove the assembly and place in a drip tray. You will probably have some spillage here. Try to cap off the hoses and clean the units.

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(Pic shows bolt locations with the assembly already removed from car)

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Step 6
Remove the two 19mm banjo bolts on the ABC pump to release the hoses. The rear hose has a bracket that is held in place by one of the AC compressor bolts. Remove that one from beneath the car. You may also find it easier to remove the rear banjo from below, but wear eye protection as it will leak when you undo the bolt.
Remove the earth strap etorx bolt

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There is another metal hose that needs to be undone from the side using a 17mm flare wrench. Undo the etorx bolt that holds the metal hose bracket to the ABC pump then move this hose out of the way.

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Disconnect the electrical connector from the ABC pump.

Step 7
Remove the 2 etorx bolts on the front of the ABC pump. You will need to move the belt tensioner using the breaker bar to access one of the bolts.
The rear of the pump is held in place with a nut through an engine bracket onto a captive stud in the pump. In order to access this nut, you need to remove the cylinder that the banjo bolts go into from the ABC pump. It is held in place by 2 etorx bolts which are not so easy to access. One is under the bracket shown in the pic, the other is at the other end of the bar and bolts into the engine block by the exhaust manifold.


To access the ABC pump bolt, use a short extension beneath the bracket pointing towards the front of the car.
To access the engine block bolt, best access is from beneath, between the AC unit and the engine. You can get an arm up there and see the bolt.

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This is the banjo unit removed from the pump so you can see the bolt hole locations more clearly.

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Step 8.
Slide the cylinder and bracket aside so you can access the last nut that holds the pump in place. Remove the bolt, then the ABC pump can be removed from the car. You will likely spill more fluid as you maneuver it out of the car. Clean up all the spillages and degrease the work area.

Step 9
Have a beer, cup of coffee or whatever floats your boat.
Wash your hands or replace your gloves before reassembly, in order to reduce risk of contaminants getting into the ABC system during assembly.
Reinstall the new pump in the reverse order of the steps above.
I used Loctite and 25nm as the torque setting for all the etorx as I replaced them.
The banjos need to be carefully done up so as not to cross thread them. (You may need to replace both the pump and the hose if you cross thread!) I tightened these as much as I could using a long 19mm box wrench. I found the rear banjo to be awkward to engage the bolt onto the thread, due to the tension in the metal hose.
Refill the reservoirs and check for leaks.
Prime the ABC pump by rotating the pulley to pump fluid through the pump. (I couldn't detect much change in the fluid levels when I did this.)
Top up the ABC reservoir again.
Put the serpentine belt back on as per the diagram below.

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Prepare your air pressurizing kit to prime the ABC pump again.
Start the car with a helper while you check for leaks. Put a few bar of air pressure into the ABC tank to prime the pump for 15 seconds or so. Keep an eye on the fluid level and top up as required to maintain the levels. Get the helper to cycle the ride height switch to make sure the car rises and lowers OK. This means the pump has successfully primed itself. Rising and lowering the car will bleed the system, as will just driving it around.

Get the helper to turn the steering fully left and fully right until bubbles stop coming into the power steering reservoir. Top up as necessary. Mine was OK after about 10 turns lock to lock.

You may need to get any old ABC error codes cleared from your car using a code scanner or DAS system. I have a Chinese DAS laptop, so I can clear my own codes.

Go and buy a holiday or a weeks supply of beer with the $7k you just saved for one day’s work…
 
If my car had ABC suspension I'd be very happy to see this.
Excellent and well produced "How to":thumb:

One for the mods to make a "sticky"?
 
Well done...where's the $8k work in that??:dk:
 
As above im sure many will thank this thread, Awesome pics btw :)
 
Fantastic - reminds me of this forum in it's best days...

Properly knowledgeable folk sharing proper knowledge.

It would make me go find a mechanic :)
 
Awesome. Thanks for such detailed information.
 
This is definitely doable at home by anyone who is capable of moderate DIY on cars, eg the sort of person who does their own spark plugs, brakes and fluid changes. It requires no specialist skills or tools other than access to the code scanner at the end, but you could take the car to a Mercedes specialist afterwards and ask them to do a code clearing, suspension alignment and rodeo if it makes you feel more comfortable in your work.
I haven't had any formal mechanical training, I have just learned what I know by reading other peoples DIY's, Youtube and workshop manuals. I do 95% of all my own car work. Recent projects include a 1972 Porsche 911 engine rebuild, clutch replacements, IMS bearing and RMS on a 2004 Carrera 4S, Air Oil separator on a 2001 996 Carrera 2, gearbox services on my Land Rover Discovery 3 and Mercedes E550.
Next up is turbo replacement on a 05 Cayenne Turbo.
You just need to bite the bullet and get on with it, small piece at a time. I calculate I saved in the order of $50k in the last 12 months by DIY mechanicing, but I have been doing a lot of Wheeler Dealering!
 
Fair play, that is a write up and a half! I've done it on my driveway afew times, it's not such a bad DIY tbh!
 
I found out that the o-rings can be replaced and the following are the part numbers:


ABC Tandem pump, part number 0034662701 or 0034665001
4x banjo hose o-rings, part # 0289976548
4x banjo bolt seal rings, part # 0279978548


I recommend replacing all the banjo seals to reduce the chance of leaks, they are very cheap.
 
Would this be the same/similar procedure on the V12tt?
Only reason i ask is that i have heard you have to lift the engine on the v12 to access the banjo bolt on the back of the pump due to limited room, however in your pictures once the abc tank is removed there seems to be much more room?
Thanks
 
Really good thread. Seeing this write up is making me me reconsider my decision to steer clear of buying a 500SL.
 
Great write up, unfortunately I'm unable to see the pics, is there any way I would be able to access the pictures. I'm hearing clicking noise on my abc pump pulley area, I'm taking it in to get it checked but I fear the worst!!...the cars probably due for it soon.....the write-up to replace the abc pump doesn't seem to bad, I think with the pics will help me deiced to do it myself....or not?.....Thank for any help
 

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