W113 Fuel Pump - PeachParts Mercedes-Benz Forum

BBAY · #1 04-20-2004, 08:59 AM

I have a 1965 W113. My early style elelctric fuel pump froze from disuse. I tore it down and cleaned it up but though it runs, it does not pump. The internal fuel filter is clean and the discharge check valve seems OK. The shear key in the impeller is intact. Any hints? Any alternative to the high dollar option of changing to the later style pump with the requiremnt for mounting and pressure regulator mods?
Thanks
BB

hookedon210s · #2 04-20-2004, 09:41 AM

I recently had the same problem with my 6.3. After freeing and cleaning the pump it still would not pump. The cause was a coked in-tank screen and steel fuel supply line built into the tank. Cleaned the screen in good carbureator solvent and freed the supply line with a coat hanger from the pump side to the tank sump and let fuel flow through to clean the line of deposits. It now pumps (and the engine purrs) but will need to have the tank cleaned and will change the primary fuel filter to ensure clean fuel.

BBAY · #3 04-20-2004, 09:50 AM

Hi: Thanks for the input. As I am testing the pump on the bench, the tank problems don't apply here, though I find it interesting that, due to the nature of the pump, there must be some head pressure for it to work. This means that, apparenty, when the supply hose is removed from the tank, the entire content empty. Very odd, and dangerous.
Regards
BB

hookedon210s · #4 04-20-2004, 10:22 AM

What you say is correct---this pump does not develop lift. Are you sure you put the impeller back in with the same orientation? I'm not sure this matters on this pump but it's worth a try. Also, is the battery connection reversed either at the battery or the pump? I know that the pump wires are sized so this shouldn't happen but you never know.

BBAY · #5 04-22-2004, 12:09 PM

I took a look at the impellor and noticed a barely perceptable difference from one side to the other. After flipping it, it began to pump normally, though leaked like hell from the weep tube. I expanded the bellows on the carbon seal and that seemed to work to dam the flood. Now if I can figure out the purpose of a 1/4 inch long, 3/16 inch diameter coil spring that fell from the carbon brush end after removing the end bell, I'll put it back in the car and pray. Thanks again for the advice.
BB

HGV · #6 04-23-2004, 01:09 AM

I thought I had a bad fuel pump for my 1969 280SL so I foolishly purchased a new pump. Installed it and it still did not run. It was a bad ingnition rotor. So I have a used but operating fuel pump that would probably fit your car. $50 plus shipping and it is yours. I need to find it in my shack if you are at all interested send me your contact info and I will call you.

Henry