Fuel pump failure

[Sundance1234]

Hi All

The fuel pump on my 1970 911E failed after I had owned the car for about a decade (These are the two inlets one outlet pumps).
On inspection the electric side of the pump was completely filled with fuel so presumably the internal seal had failed between the pump side and the electric motor side?
I replaced it with one supplied by Porsche GB (they all seem to be refurbished units).
It failed in a similar way after about 14 months and Porsche have just supplied a replacement.

Is this a normal mode of failure for these pumps? Ie the internal seal fails or is it possible I have some other problem?

thanks

Dom

[Magyar Kiwi]

Hi
Bosch electric fuel pumps common to classic Porsches, like yours, all operate with the electric side of the pump filled with petrol, for lubrication and cooling.
There is no internal seal between the electrical and pump sides.
Hoping this helps.
Cheers

[Discseven]

I've had Bosch pumps last for several years and one that lasted for less than 12 months.

[Sundance1234]

Originally Posted by Magyar Kiwi

Hi
Bosch electric fuel pumps common to classic Porsches, like yours, all operate with the electric side of the pump filled with petrol, for lubrication and cooling.
There is no internal seal between the electrical and pump sides.
Hoping this helps.
Cheers

What ? so the armature of the motor spins in petrol ? ...... surely not? Wouldnt the fuel short out the electrics?

[Alan L]

The pump relies on the fuel for lubrication. Which is why it is not advised to run it dry (out of fuel).
There are also a lot of fake 'Porsche' pumps in the market these days. Many documented issues with them on this site.
I recently acquired a 2nd hand genuine pump rather than risk buying a new one.



Don't know if this is the type of pump in a 1970 911, but it is for most 911s in the 70's

[wazzz]

Originally Posted by Sundance1234

What ? so the armature of the motor spins in petrol ? ...... surely not? Wouldnt the fuel short out the electrics?

Fuel doesn't conduct electricity. Many fuel pumps, like those for Porsche 924 and others, are immersed in the tank with their wires and contacts bathing in fuel. No air so no risk of fire.

[Sundance1234]

Thanks everyone.

Thats amazing I never would have thought they filled with fuel.

good to know that you must never let them dry out.

More proof that you should drive your porsche regularly ot they ......... 'compalin'.

Thanks again for your help

[Vrod]

I have one that works. And has not been used for 50 years . Are you interested ?