DIY fuel filter fix

[JohnH]

I have an old BMW E28 520i, 1986. The in tank filter has failed allowing a lot of crud into the fuel pump which has now given up the ghost.

Change the filter, you say, well I would except they are over £300, so I was looking to fix the one I have.



Theres not much to it. The alloy potion contains the float and the "foot" on the bottom, the filter.



What I would like to do is glue some filter material onto the bottom of the foot replacing the torn filter.

So the question is, is it possible? What glue do I need? What filter material?

Anyone got any ideas?

 

[Craig-SM]

Filter sock and zip tie to the tube.

 

[Anguz]

Fetch another one from a scrappy.... dont they come out from under the rear seat when you rip the seat out?

 

[8ob]

You could buy the gauze and bond it onto the existing pickup https://www.stationaryengineparts.com/Brass-Fuel-Filter-Mesh.html

May get away with a wrap of the gauze around whats there and wire ties or cable ties to hold it into place.

Bob

 

[james butler]

Filter sock and zip tie to the tube.

second this and ive used metal cv clips to hold it on

 

[julianf]

I'm not familiar with them, but can you strip out all the in-tank gauze and put a "rock catcher" inline filter on the line as close to the tank as possible?

 

[8ob]

That plastic filter extension is worth another 15 mmish in pickup length, to do away with it may leave a few gallons in the tank that will never get picked up, running out of fuel might come before the red line or empty is shown on the gauge. I would wrap what’s there.

Bob

 

[JohnH]

Guys, thanks for all your ideas.

I had wanted to stick some filter material to the foot, but after thinking about it I think the "filter sock and zip tie" approach is probably the best (and easiest). I think I need a filter of 40 microns or better and most of the ebay socks seem to be 70 or more. The foot is 125mm long and 50mm wide and 10mm thick. Would the socks fit over that and up the tube?

Bob, I like the look of your brass mesh but it appears to have an "aperture " of 0.25mm (ie 250 microns), which would rule it out.

Meanwhile I've cleaned the tank out and coated it internally using POR15 materials from Frost https://www.frost.co.uk/por15-basic-big-fuel-car-tank-repair-sealer-kit/ which seems to have done a good job.

I fitted a new external pump and filter and will finish putting it all back together today swmbo permitting.

The internal filter is accessible from the boot so I can fit that later.

 

[Anguz]

Are you certain the fuel wont eat the zip tie?

 

[Matrixx]

Wow a Haynes manual, I used to use them a lot, I always found that one simple instruction could take hours to do, and on my Escort 1.6 CVH every single bolt and nut were rounded off.

 

[JohnH]

Are you certain the fuel wont eat the zip tie?

You.re right, so a twist of wire instead.

 

[JohnH]

Wow a Haynes manual, I used to use them a lot, I always found that one simple instruction could take hours to do, and on my Escort 1.6 CVH every single bolt and nut were rounded off.

Yes Haynes 1560, by far the best E28 manual available and that includes the official BMW manuals. I was trying to find the location of the secret tank bolt. The thing I like about the Haynes is that they use tweeked copies of the original schaltplan wiring diagrams. On these early manuals they follow the step by step procedures listed in the BMW factory service manuals, so they are well worth a couple of £ off ebay. Having said that the 1960s early factory manuals are truly excellent, the later microfiche stuff is carp by comparison.

 

[Anguz]

Assume you have sorted this by now... but just come across this in the workshop

 

[james butler]

You.re right, so a twist of wire instead.

steel cable tie used on a cv boot

 

[JohnH]

In the end I couldnt use anything to keep the sock in place. The hole in the tank is only a gnats larger than the filter housing/boot, it is quite a tight fit around the alloy tube. so for now should be okay.

I have bought some 35 micron nylon mesh and a suitable glue, so at some time in a warm future I'll give it a go.

 

[Anguz]

What size hole did the originall filter have? If its the same as tne one i have you can have it for postage

 

[sardine]

You.re right, so a twist of wire instead.

You can get metal zip ties.

 

[knighty]

as julianf said, remove the filter and fit an inline one outside of the tank

it's what a lot of people running biodiesel/veg oil do

something like this.... https://www.ebay.co.uk/itm/171163995430

or a smaller one if you're tight on space

 

[Keithmac]

I might have a motorcycle one kicking about at work.

Cable ties are fine in fuel, plenty of oem fuel pump assemblies use them for securing cables.

 

[james butler]

You can get metal zip ties.

yup

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