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MG TD TF 1500 - Fuel pump ground?

I bought a new reconditioned fuel pump on eBay and just picked it up... is there any way to tell if it is a positive ground unit (or is the neg ground a different one all together). There is a part number i believe is 4060 on the backside. It looked identical to one on a pos ground TD a friend is working on, but we couldn't see the backside and he didn't want to remove it?

as usual...thanks in advance
g.b.lawson '53TD

Amazing, in 25 years of tinkering with MG's I never even thought about pump-polarity, but after changing polarity of my Y I don't seem to be talking about anything else.

Early fuel pumps are NOT earth sensitive, later or properly overhauled pumps are because of a fitted diode that prevents pitting of the points.

This diode can be reversed to change polarity (or removed in case of emergency when your +ground car needs a new pump and a only -ground pump is available and (yes, David) the diode should be replaced properly when you arrive home).

See the following links for more info
http://www.team.net/sol/tech/supump.html
http://www.team.net/sol/tech/SU-diode.html

We discussed it also on: the Thread: negative vs positive ground on midget Technical.
Willem van der Veer

GB - The number you found on the back of your pump is the part number of the pump body casting. If the pump is a SU low pressure pump, then the part number is AUA 25 pump and Willem is correct, it is not polarized unless whoever rebuilt it put a diode or transistor in it. You can tell by taking the end cover off of it and match it to the picture in the Moss catalog or send me a picture (jpg foremat and make the picture no more than 3 X 5 so the file is relative small - I'm still on dial up) of the area under the end cover and I will let you know if you need to worry about the polarity. Cheers - Dave
David DuBois

This thread was discussed between 26/06/2004 and 28/06/2004

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.