Never really put any thought into this but as I’m alsways looking at pictures of old fiat 500’s, I happen to notice that people have there fuel filters in different locations. I never questioned it due to my fiat came with it after the fuel pump but the more I look at pictures I see the fuel filter before the pump a lot of people’s 500’s. I attached a picture of both. Take a look. What is the proper location for the fuel filter before or after the fuel pump?

My car came with the filter between the pump and carb, although I believe the correct position of the filter should be before the pump, this to protect the pump from debris, also so that the filter is not pressurised, I have not corrected mine as it hasn't proved to be a problem, yet! Its been OK for 5 years so far.

MIne is also after the pump. I was just thinking to protect the pump I should probably put it before it since that what I have been told and seen the most.

berkeleyman said:

I believe the correct position of the filter should be before the pump, this to protect the pump from debris, also so that the filter is not pressurised, I have not corrected mine as it hasn't proved to be a problem, yet! Its been OK for 5 years so far.

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I would recommend changing the filter more frequently than every five years but I suppose it depends on how much driving you do. But there won't be reduced protection for the carburettor with the filter located between it and the pump. For a short time there might be a slight back-pressure in that length of pipe when the carb is full and this might be thought to put a bit of strain on the filter and its connections. Putting it before the pump means it will be in a slightly cooler place and so will reduce the exposure of a relatively large surface area of fuel to vaporisation. If the filter cracks or the pipe ends fall off, a filter between the pump and carb will possibly result in fuel being pumped in the direction of the hottest and sparkiest end of the engine. Before the pump a failure will still mean a flow of fuel under syphonic pressure.
If I had one of these filters I would take Tony's Vitesse advice and fit one which is not made of fragile plastic. In my case I would use a metal one so that I wasn't troubled by the fact that it often appears to be full of air all the time (like me ) when you look at the engine on tickover
For the same reason I would also try to stick it out of sight, under the bonnet, close to the fuel tank. By keeping it higher than the fuel in the tank it would avoid dangerous siphonage of fuel if it failed. It would also be away from potential damage by heat and vibration and be more protected from dirt and other contaminants.

I have a small metal fuel filter, of the type that can be dismantled, between my pump and the carb. The reason for this location is two-fold---(a) it was the easiest place to put it and, (b) the 'T' piece for the fuel return (from the carb) did not leave a lot of space before the pump to locate it. I have been advised by 'clever people' that the best place to locate the filter is just outside the fuel tank, however, this has 3 slight logistical problems. (1) if it should leak, it will be leaking into the car, (2) the factory OE fuel pipe is of the 'hard' variety which makes it difficult to fit the filter into and, (3) prior to taking the car off the road over the winter (when normally I am working on the car) I like to drain the tank and run the carb dry. Modern fuel (even 'Super') has ethanol in it which hates classic car fuel systems, so by removing the fuel, which will probably 'go off' over the winter anyway, I reduce the chance of fuel induced damage. Having the filter prior to the fuel pump, whether it is at the tank end or just before the pump makes it more difficult to drain the tank, which I usually do by removing the feed-pipe into the fuel pump and letting the fuel from the tank just flow into a container. "Purolater" (among other brands) do a very good, small metal filter that can be dismantled for filter element cleaning, or renewal.

the hobbler said:

I have been advised by 'clever people' that the best place to locate the filter is just outside the fuel tank, however, this has 3 slight logistical problems. 1 if it should leak, it will be leaking into the car,

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"Compliment" accepted.

But maybe I'm not so bright? I would stupidly prefer the smell of petrol in the passenger compartment to a fire in the engine compartment.

Hi Napolikid

I have my filter fitted at the top of the fuel tank. It is a chrome and glass item that can be stripped and cleaned. Also, I placed it there to ensure if anything was to come from the tank it wouldn't enter the small fuel lines, let alone the pump and carb. It works fine and so far has caused no flow problems at all

Cheers
Hugh Jarce (aka Gary)

Hi NK, My installation has an electric pump in the forward bay at the side of the spare wheel, and I have placed an in-line filter between the tank and the pump for three main reasons. 1. The tank in the 500 is notorious for rust. 2. I don't want to contaminate the (expensive) pump. 3. I have used stainless steel braided fuel pipe and don't want to pump possibly contaminated fuel down the whole length of the car piping to the carb. The filter is an ebay buy and cheap and easy to change.

Ian.

Well that's cleared that one up eh?