fuel pump/filter assembly

Post your E12 technical questions and comments here. Please, no off-topic posts.

Moderators: Mike W., Pierre

Post Reply
garyinwestoz
Posts: 390
Joined: Thu Jan 29, 2009 9:05 pm
Location: perth, australia
Contact:

fuel pump/filter assembly

Post by garyinwestoz »

Is there a correct way in which the fuel pump/ fuel filter assembly is orientated.

Ive just pulled apart an assembly due to cracked fuel hoses, and re-assembled it back the way it was, but feel that the hose is too close to the output shaft.
I have another assembley here and it has a different arrangement.

fuel pump assembly diagram
Image


fuel pump out of car - just a rubber hose between pump and filter

Image

that pump assembly cleaned up and installed - hose is very close to the output shaft

Image[/url]

a spare pump assembly I have - it has a metal tube between filter to pump which would be No 4 in diagram

Image

My 77 528i is different - it has 2 filters

Image
74 525 auto
76 525 - 4 speed, LPG and holley carb- restoring
77 528i- 4 speed manual
77 528i -4 speed manual getting rusty
79 528i auto - a SA car?
80 528i auto - ready to relicense
81 528i +3.5ltr - auto - restoring
86 525e 5 speed manual- dd
canada karl
Posts: 1058
Joined: Tue Jan 06, 2009 3:50 pm

Re: fuel pump/filter assembly

Post by canada karl »

On some E12's it appears that at some point the PO has moved the filter up to the left front side of the engine area because it would be easier to change. I've seen this on a couple of cars but ideally the filter should be "before " the pump to prevent the crap at the bottom of the gas tank from getting into the pump.
You can run your pump filter closer to the pump. You don' have to locate it that close to the output shaft.
1976 530i. BMW 59 Triumph TR3A(rolling resto). 67 Triumph TR4A(salvageable). 86 900S Winter car
User avatar
Lock
Posts: 456
Joined: Sun Oct 04, 2015 1:51 pm
Location: Olympia, WA
Contact:

Re: fuel pump/filter assembly

Post by Lock »

I've done that, moved the filter to the front left by the battery, it's easier to change and doesn't get too hot. I don't like the tangle of lines running every which way by the pump, it feels like an afterthrought on a chassis designed for a carburettor. There's a F5 FAQ on fuel hoses and you're supposed to buy BMW right-angle hoses which makes it cleaner.
There's also a sock filter in the tank that is always recommended to clean or replace when replacing the fuel pump, and you'll want new seals if you take it out. I changed out the lift pump and inspected the sock and the tank but it was rust-free and there wasn't any visible dirt on the sock. Unusual for 30+ years but maybe it's all been sucked thought the pump into the after-pump filter.
1979 528i - M30B34 with 9.5:1 B35 pistons, 5-speed conversion G260/6, e28 rear subframe, e34 LSD 3.9:1, glass sunroof, e30 elec speedo, cruise control
garyinwestoz
Posts: 390
Joined: Thu Jan 29, 2009 9:05 pm
Location: perth, australia
Contact:

Re: fuel pump/filter assembly

Post by garyinwestoz »

I ended up using the metal extender from my spare fuel pump assembly with a short bit of new hose.


ie this one
Image

clears the half shafts nicely now.

Image

but I agree - looks to me that the arrangement could be made better - I wonder if the Alpina improved the layout?
74 525 auto
76 525 - 4 speed, LPG and holley carb- restoring
77 528i- 4 speed manual
77 528i -4 speed manual getting rusty
79 528i auto - a SA car?
80 528i auto - ready to relicense
81 528i +3.5ltr - auto - restoring
86 525e 5 speed manual- dd
Post Reply