Fuel Pump Wiring

[DavidBrough]

I have the old style long fuel pump but can't remember which way round the wires go, does anyone know which terminal is positive and which is negative. Also, do the wires exit the boot through the plastic drain tube as in the photos.

Thanks

[DavidBrough]

Attemp 2 at uploading all the pics.

[George Des]

David,

It makes no difference on the old style pump which wires go where. Unlike on the smaller pump, the armature will only spin one way--the proper way. Perhaps more important, is the orientation of the pump vane if you disassembled it--the thin edge of the vane teeth point upward toward the can. If not oriented properly, the pump will spin in the proper direction, but no fuel will flow out of it. That being said, if you are a stickler for detail, the terminals are marked and you'll be able to see a number stamped into the side of the can with a number 30 under the left terminal and a number 31 under the right as you're looking at the can. As I recall, the 30 is negative (brown wire) and 31 positive (muticolored wire) but check this out to verify with a wiring diagram. The wiring does go through a rubber sleeve before it connects to the pump terminals. Hope this helps.

George

[mbzse]

.../...the terminals are marked and you'll be able to see a number stamped into the side of the can with a number 30 under the left terminal and a number 31 under the right as you're looking at the can

The terminal 30 is +12 Volts, a black/white/red wire. Terminal 31 is earth, a brown wire
/Hans in Stockholm

.

[George Des]

Hans,

Thanks--you are correct. 31 is the ground and should get the brown wire attached to it. I had it reversed. I can see where David's pump has been painted and it may be difficult to see the stampings, but 31 is on the right hand side as you look at it.

George

[tel76]

David, That cooling tube looks very close to the body and could touch,why do you not remove it? when i fitted mine i remived the pipe and used W113  oil sump plugs to blank it off

[DavidBrough]

Thanks guys I've found the numbers and the connections now make sense.

Still not absolutely sure about the drain tube but now everything is in and connected it looks right and I'm pretty sure that's how it was when I took it apart.

[George Des]

David,

I took another look at the wires exiting your boot. On my 230 SL, I believe the pump cross mount is mounted on the body cross member that is a little to the left of where yours is. Also the pump cross mount has a hole through the center that lines up with a whole on the body cross member and that's the hole the wires are fed through with a rubber not plastic sleeve. May be some differences between the 230 and the 280s in this regard. Hope this helps.

George