Out Banjo persistant leak

[sgnimj96]

    I just got a 1.6 n/a.   Previous owner was not good to it,  but the engine is still healthy.    After fixing various things I still have this return banjo leak that is perplexing:  new copper washers,  return line seems clear (blew air through it), rubber hoses are good and tight,   engine runs fine.      However,  when I ran a short fuel line from the return banjo straight into a bottle the leak is much less.      It idles fine,  but leaks a steady drip from the out banjo.        I'm really not happy about having to take that banjo bolt off-    I've  never seen torqued copper washers leak so easily.     The PO had rigged a lot of stuff ridiculously wrong.     The idle adjustment screw is gone and I was told the fuel screw was turned up.   

[theman53]

I would make sure both copper washers are clean and not cracked or something. I would make sure the banjo isn't cracked either. A guy on here says he sands the copper washers with fine sandpaper and then heats them to blue with a torch. He said they seal better for him. I personally haven't had an issue or used this method, but would give it a shot if you have that bad a leak.

Also, if you reused the cloth line after pulling it off, then that is your problem. Replace those as they leak always.

[sgnimj96]

thanks for the reply
  I'll try cleaning and heating the washers,     I was starting to worry the pump was over pressuring the return with the odd fuel/idle set up.   It's a 81' scirocco that someone put a diesel in.    Then someone else got it and thought it would be faster with an electric fuel pump and the fuel screw turned up.    There is a long list of dumb stuff.    Good thing he sold it.

[8v-of-fury]

Hey now, don't be dissing the electric fuel pump.. It is my first modification when I start working on one of these bad boys. That and clear fuel lines, best things to do if you haven't



Also, yes it could be ridiculously high internal pump pressure.. he may have tinkered with it if he has done some other funky stuff. I'd be checking it, by making one of these;



However, before you do any of that.. when you remove your OUT bolt, make sure it is not gunked up inside.. that will cause stupid high pump pressures, and sooner or later you will start blowing seals out.

[ORCoaster]

8V  you forgot to tell him about the tiny screen inside the OUT Bolt and the teeny tiny hole in it where the return line goes.  Both of these need inspection and air through them.

Nice gauge set up but again, tell him where it goes to measure the IP pressure. 

You may be correct on the PO pounding in the regulator on the front part of the pump.  Refer to the sticky from the home page that has the diagrams and such in it so you can get started on understanding where the fuel comes and goes in these critters.

I have a take off on the out bolt that provides me with IP pressure.  The gauge is inside the car with all the others.  Lots of others. 

Good luck, I hate leaks like that. 

[8v-of-fury]

Ahh yes, my apologies.

My second picture is an air tank gauge (yes it is broken, they should sit at zero). The bolt on the left is a drilled and tapped OUT bolt. When you take yours out you will see that there is a very small hole on the side of it above the threads. It is this small hole that regulates the internal pump pressures by the way of being a restriction. You need to make sure the screen is free of debris, and gunk.

As can be seen here, I have the gauge in my out bolt. With separate testing lines in to a jug of 2-stroke oil.




And here is a video of said excursion. My pressure was WAY LOW, as I had some internal pump issues.. but you're looking for around 45-47psi at warm idle I believe.

[bajacalal]

About washers-

I sand them with fine sandpaper, like 1000 grit by laying the sandpaper on a smooth surface and moving the part back and forth in an figure 8 motion.

I don't heat them though, I tried that once and it melted the washer.

[8v-of-fury]

I don't heat them though, I tried that once and it melted the washer.

Too hot.. lol

[libbydiesel]

The copper washers and banjo fitting seal around the outside of the OUT bolt and so are not under any pressure at all, ever, unless there is a blockage in the return line to the tank. 

[8v-of-fury]

IIRC he has blown through the fuel lines.

I think you just may have to crank it down a little tighter. You have to crush that copper washer for it to seal.

[R.O.R-2.0]

electric primer/lift pumps are a GREAT IDEA on these old cars..

i, as well, add an electric pump to any new cars as well.. they really DO help out..

plus, if/when you run out of fuel, all you have to do, is turn the key on, and let the inj pump re-fill, then hit the key..

that eliminates the need to crank for minutes at a time to re-prime your fuel system..

have you confirmed that it IS INDEED the out banjo leaking, and not the throttle shaft seal? they are both on top of the pump, and in close proximity..

[ORCoaster]

I use the figure 8 pattern as well but when heating I only use the tip of the torch flame not the internal blue tip.  It takes like seconds to turn them blue and then they smash better.  Clean extremely well on all sides of all parts.  Why embed a bit of dirt and make it leak again?

[745 turbogreasel]

I hang the washer from a screwdriver, and heat it over a burner on the stove till it just starts to glow.
Doesn't take much.

[libbydiesel]

IIRC he has blown through the fuel lines.

I think you just may have to crank it down a little tighter. You have to crush that copper washer for it to seal.

The injector jumpers and return line to the tank are similarly on the outside of the OUT bolt and so are not under any fuel pressure at all unless there is a restriction to the line to the tank. 

[8v-of-fury]

They still utilize a crush washer for a reason, no? To be crushed lol.

You can't tell me there is 0psi on the return, it does not just trickle back to the tank. The pump forces it back there.