spitanddirt

I just turned over 148,000 miles on my 2000 A8. I've been thinking I should order a pump just in case. Well, apparently my car "heard" what I was thinking and decided to beat me to the punch. It died in the parking spot at work as I was pulling into it. To make a long story short, I ordered a pump from ebay seller OTOMOTECH and I had it in 4 business days from England to my midwestern home.

The pump was completely identical to the factory pump.

I did find one odd observation though: my factory pump has both Audi and VDO/Siemens numbers laser etched into the outer casing, the new VDO/Siemens pump had visible marks where sandpaper was used to remove the numbers... This, of course, leads me to believe that I am getting the EXACT same pump that is sold to Audi to be installed into their $700+ fuel pump assemblies.

In any case, I love ripping stuff apart to find out how things work and why failure occurred in the first place. I can say with certainty that the pump is constructed very well, and if not for the brushes/commutator wearing out, I bet this pump would last well into the 200,000 mile mark. See for yourselves....

If you look closely enough at the third and fourth pictures, you can see how far the brushes "ate" into the copper commutator of the motor/rotor assembly.

One more thing, this proves that it doesn't matter how low you run your tank on gas as long as you don't run it empty. The urban legend about how you should never run your tank below 1/4 is absolutely bogus! What you see is what you get! The fuel runs directly over the rotor and past the brushes cooling everything as is passes through. The gasoline also serves as a mild lubricant to the bushings that keep the rotor spinning.

The main reason pumps fail prematurely is because people fail to replace their fuel filters at least every 24,000 miles or two years. I personally do mine every 12,000 miles or every year. Because the fuel filter is so restricted in the first place, more amperage is required to turn the pump in order to maintain pressure in the fuel lines. This, in turn, generates more heat in the windings of the rotor and eventually breaks down the coating of the windings and causes a short.

When a short circuit occurs in the windings of the pump there is no longer an adequate path for electricity to flow which generates electromagnetic force that allows the pump to turn in the first place. The excess amperage required to turn the pump also causes excessive wear and tear on the brushes, thereby also rendering the pump useless.

Fuel filters = cheap. Fuel pumps = not cheap. This applies to all gasoline/petrol vehicles with electric fuel pumps.

TerminA8r

Thanks, good info.

klm187

I guess I am overdue for a filter and a pump as I have never changed my filter myself. Perhaps this has been lumped into one of the service intervals that I paid to have done. It behooves me to check now that I know. Better that than be stranded somewhere with nary a fuel pump in sight.

audijim113

Thanks for the reminder. Just bought D2 with 145K, Not sure when filter was changed. Will do it ASAP.

Pchelka01

spitanddirt what were the car symptoms when the pump died?

spitanddirt

No symptoms, I flat out just died. But here's a hint, start your car and crawl into the trunk and stick an ear directly on the fuel pump access cover. If the pump sounds anything but steady and even, it's going to fail soon. Mine had a "blip" in the steady tone about every couple of seconds while it was running. In my honest opinion now, it's best just to change it at 145,000 miles or less and be done with it. Don't question the facts, just change it before it leaves you stranded.

PuiaKa

http://youtu.be/maF2MhmfF7g

pocketchange

Excellent tutorial.. Thank You Sir.

I did my fuel pump about a year ago (@125K) and it looked identical. Much easier in the driveway than the expense/hassle of being stuck someplace.

Kneale Brownson

Whatever you do, don't use the car's jack to hold it up while you work under it.

Adjuster

Holy Jackstand! Get that man a jackstand STAT!

Those stock jackstands are known to be widowmakers folks. I'd never get under a car with one, WITHOUT a jackstand under there as well.

Good tip on "dressing" the crush washers on the banjo bolts.. Just use some very fine sand paper, say p1000 wet/dry on the washer, and a flat surface. (Glass works well.) Few seconds over the sandpaper, and it dresses up the crush washer, and it's ready to be crushed/used again.

No need to replace them, just dress them up. (Worked with a guy who used to just slide them on his metal work bench top, and that cleans them up well too, but not as good as p1000 sand paper does.)