Hi,
I'm also looking for a A-class pump wiring.

My pump har four wires; plus, minus, alternator (blue) and a green wire. What's the green wire for?

 

Ivar,

I am certainly no expert on this but I'll share what I've learned. I still have an interest in knowing the answer as well, in case you or anyone can shed any more light on the subject. What I was told was that the green wire is apparently for a speed sensor of some sort. My guess is that it works with the programming in the pump to reduce the degree of power assist as speed increases. But that's just my guess. I would really like to know more myself.

Because I was nervous about how this four-wire pump would perform for my application that is wired for three wires, I bought another BBA Reman unit, this time with three wires, so I wouldn't have to wonder how well the pump would work without the green wire hooked up. The part number on the four-wire pump is A 168 460 0601 and on the three wire pump is A 168 460 0501. To my knowledge, all the pumps with 0101, 0201, 0301, 0401, and 0501 are three-wire pumps and the 0601 is a four-wire unit.

As a result of this, I now have a brand new (actually remanufactured), unused four-wire pump that I'd like to sell if anyone is interested. I will sell it for $400 US plus shipping from Seattle.

 

Rob,
Thanks, that sheds light on the four cable setup. I have suspected that the green is supposed to be connected to a speed sensor, but wasn't shure.

I'm experimenting a bit with my 1968 Mercury Cougar and getting rid of the classic pulley powered steering pump.

Maybe you have seen this British blokes page about the A class pumps: Bert Rowe's-Mercedes-Benz 'A'-class info. Steering height adjustment Steering column, Power steering pump.
Quite helpful info.

I'm located in Sweden, so I can pretty easily get hold of A class pumps (there are more pumps fore sale on the UK Ebay than the German Ebay).

 

Ivar,

Thank you. Yes, I had seen that article. In fact, the reason I replaced my pump is because the previous owner had installed a relay (or solenoid) external to the pump to solve the problem described in that article (in which the pump fails to shut off). Though it may be a clever fix, it was not pretty and I wanted to get rid of that solenoid. So I bought a new pump. Two, actually!

I wish there was more extensive documentation available about the wiring and internal programming of these pumps. I haven't found anything. But then again, I'm not very well connected with the Mercedes world, let alone with the A Class cars that don't even exist in the US. I would think there should be some Mercedes and/or VDO technical documentation, but I have uncovered nothing from web searches. If you or anyone else can help, I'd appreciate it.

A 68 Cougar, eh? Now *that* I can help with. If you need an original, belt-driven power steering pump for such a car, I'm sure I can help get one for you over here. I spent a wonderful summer in Goteborg in 1980; I was amazed at how many old American cars are running around Sweden, obviously loved by their owners. There are not many 68 Cougars left here either, but that pump was probably not unique to the Cougar and was likely used on other cars of the era (such as the Mustang). So if you have problems sourcing one, I have some connections.

Rob

 

Rob,

I'm going to replace my belt-driven power steering with a A-class pump, so I don't have to use the original. Thanks for the offer, though.

I'll let you know if/when I find out more about these pumps.

All the best!

 

The main problem with these VDO pumps (3801) is the four Darlington transistors that burn out with monotonous regularity.:frown

They are in a TO263- package and cost about 1,50€ each.

Sequence for replacement is;

Pop off cover, very easy as it's a loose fit and half the problem, a thin smear of silicone is a good idea on reassembly.

FIRST, unsolder the blue wire from the connection bridge.

Next; unscrew the two screws that hold the capacitor housing to the connection bridge and remove the cover, cables and capacitors in one. Remove the two screws from the pump motor and bend the cable up and away.

Now with a very hot soldering iron, apply heat to each of the legs holding the bridge to the board, a small screw driver under the tab will 'pop' it off as the solder melts.

remove the four small screws holding the bridge.

You can now clearly see the board and the four darlington transistors, usually with a nasty hole in them as above, repeat the heat and pry to each of the transistor legs, all 8 of them, then in turn apply heat to the tab at the end of the transistor and gently lift it of, do NOT lift too soon and take the track with it.

You can now reverse the procedure applying a THIN 'tin' of solder to each leg and tab and 'sweat' them back onto the board, not TOO much solder and fit bridge, etc and don't forget the blue wire. . :smile

 

Great post Black eagle!

Please can you give details on the part number for the Darlington transistors? The link points to a 3 pin transistor - can that work? Which pin do I ignore?


(Sorry about the daft question)

Vic

 

 

Hi Black eagle,

Great information, thanks!

Would you say that this is the transistor? BUB323ZT4G - ON SEMICONDUCTOR - Bipolar (BJT) Single Transistor, Darlington, NPN, 350 V, 2 MHz, 150 W, 10 A, 500 hFE | Newark element14

Or do you have a part number?

Thanks,

Vic