Actually looking at these photos it looks like the filler tube is going up hill. It might be a misleading photo angle but I wonder if some adjustment can be made.

Got me on a mission now. Found this with Google images. It has the extra breather.

Steel tank? If so I assume rust hasn't set in and caused problems at the internal end of the vent pipe?

Sadly it would mean a further opportunity to lighten your wallet. 😞

 

Looking at 14, it just appears they moved from the vent to atmosphere to vent to the tank input and I don't think that's going to be your issue myself.

I mean if it's venting successfully to atmosphere, then bar the pollution/flamable vapour escape risk, the flow of air in isn't going to be any faster if you then force the vapour back down the filler pipe.

 

Of course I could be wrong.

It's not clear to me from the diagram why 12/13 connects up to pipe 30, except perhaps as a fuel supply and 28 being the return (or the other way around).

 

If that's the case, then is the 8/11 pipe actually a vent, because if not then you would need pipe 14.

All the joy of an older car hey

 

I have to say though, I'm loving seeing rusty going around, it's an iconic car

 

EDIT:

 

I posted before I saw the last post with pictures. That looks like it's a plastic tank although I'm not sure the up hill filler would cause the sort of problems you are seeing.

 

Interestingly the shape of your tank and their tank is different as you can see yours rises to a peak on the left, but their tank is far more flat on that side. I assume your tank has the vent pipe from the peak of the tank which is why the shape is different?

 

Definately go for the custom baffled fuel tank in shiny/expensive material option  👍😂😂😂

 

One further, potentially very stupid thought... when it's on a go slow fill, have you tried opening the boot lid?

I only ask as I can see you've had some painting done in there and I'm just wondering if somehow a boot vent flap or similar is blocked.

I can't imagine for a second it would be that, because there is no way air should be being pulled in from that area, but then it's another stupid thing to rule out if it was fine at some point in the past.

Edited 26 May, 20224 yr by cheezemonkhai

28/30 is the later revision replacing the setup I have. It adds a rollover protection valve. 
I have solved part of the mystery with pics from a friend’s car.

 

 

You can see there’s a double outlet going to the vent I have plus a fat one that links back to the filler.

 

This is mine

 

Single small pipe. It makes sense that the small pipe can’t vent enough air to compensate for the fuel flow.

 

And my filler tube has been welded up where the connector should be.

 

 

How odd!

 

I know the car was hit hard from behind once when parked and had extensive repairs so maybe the tank is from a different model, or maybe some repair person did this for a reason but it’s weird.

 

It has always been hard to get petrol in.

 

it is a steel tank by the way.

 

 

Edited 26 May, 20224 yr by RobClubley

Hi Rob, that fuel filler pipe does look pretty flat - if not actually "uphill" I recall a Toyota flat deck that had a filler like that, and it was a bas7ard to fill unless it was parked on a slope.

I think that could well be your problem Rob, as the twin pipe is probably 2 fold, one to return fuel to the tank in an overfil, and one to vent actual fume pressure, (my moneys on the clear one for that)

 

It looks like your plastic pipe on the original setup is returning from the tank to the tank rather than the filler neck or is that just camera angle?. If that's so, the pressure can't go anywhere while the fuel going in is consuming the available airspace with nowhere to go. You really want to create a closed suction loop in the filler so one drags the other along, in other words the fumes being pushed into the neck above the fuel creates a depression to draw the new fuel in. Atmosphere venting may not be cutting it anymore with modern fuel station pump delivery rates being higher now than when Rusty was born.

 

Can you not get a local specialist to place an elbow in for you?. i'm wondering if the previous repairer did not fully understand the system, and welding was simpler as a solution.

 

Just out of interest Rob, have you had your breather pipe off the tank and checked the elbow is clear with a length of welding rod or similar or was that the pipe you blew through?.

On 26/05/2022 at 15:04, RobClubley said:

28/30 is the later revision replacing the setup I have. It adds a rollover protection valve. 
I have solved part of the mystery with pics from a friend’s car.

 

 

You can see there’s a double outlet going to the vent I have plus a fat one that links back to the filler.

 

This is mine

 

Single small pipe. It makes sense that the small pipe can’t vent enough air to compensate for the fuel flow.

 

And my filler tube has been welded up where the connector should be.

 

 

How odd!

 

I know the car was hit hard from behind once when parked and had extensive repairs so maybe the tank is from a different model, or maybe some repair person did this for a reason but it’s weird.

 

It has always been hard to get petrol in.

 

it is a steel tank by the way.

 

 

Is it possible to source the later revision tank or get one built for your car without spending eye watering amounts?

 

I imagine the rollover protection valve would be a nice safety upgrade if you’re looking to fix it. 
 

Goodness knows why they welded that steel tank up. I do wonder if the back panel is straight and the fuel filler where is should be if they resorted to that sort of thing.

 

I hate it when people bodge it because they CBA, but hopefully you can sort it at reasonable cost.

1 hour ago, kentphil1 said:

I think that could well be your problem Rob, as the twin pipe is probably 2 fold, one to return fuel to the tank in an overfil, and one to vent actual fume pressure, (my moneys on the clear one for that)

 

It looks like your plastic pipe on the original setup is returning from the tank to the tank rather than the filler neck or is that just camera angle?. If that's so, the pressure can't go anywhere while the fuel going in is consuming the available airspace with nowhere to go. You really want to create a closed suction loop in the filler so one drags the other along, in other words the fumes being pushed into the neck above the fuel creates a depression to draw the new fuel in. Atmosphere venting may not be cutting it anymore with modern fuel station pump delivery rates being higher now than when Rusty was born.

 

Can you not get a local specialist to place an elbow in for you?. i'm wondering if the previous repairer did not fully understand the system, and welding was simpler as a solution.

 

Just out of interest Rob, have you had your breather pipe off the tank and checked the elbow is clear with a length of welding rod or similar or was that the pipe you blew through?.

 The plastic pipe I have goes under the tank and out to atmosphere through a grommet in the boot floor. That is the one I blew through it's definitely clear but it's just not big enough to move enough air to compensate for fuel going in.

 

40 minutes ago, cheezemonkhai said:

Is it possible to source the later revision tank or get one built for your car without spending eye watering amounts?

 

I imagine the rollover protection valve would be a nice safety upgrade if you’re looking to fix it. 
 

Goodness knows why they welded that steel tank up. I do wonder if the back panel is straight and the fuel filler where is should be if they resorted to that sort of thing.

 

I hate it when people bodge it because they CBA, but hopefully you can sort it at reasonable cost.

 

I'm talking to a local guy who has a shed full of old Audis in various states, he might have a tank and filler spare. Need to be careful though as the Coupe GT has a similar tank but it's 71 instead of 91 litres.

 

Getting one built would be expensive and would require the car to be re-certified at a cost of about $1000. Though technically the modifications to the tank and filler as they are would need a cert too.

 

I do plan to remove the ABS as it's leaking from the ABS unit and not functioning and parts just aren't available to repair it. Again that requires a cert.

 

A cert is basically a full safety check by a specialist with any modifications listed and stamped onto a plate which has to be riveted to the body in the engine bay.

It's required on a car with certain modifications, so that it can go through the Warrant of Fitness process (MOT).

 

A cert is a one-off process for any and all mods and if further mods are made it had to be re-done at full cost.

I would still slip the pipe off the tank and have an exploratory prod with some wire.

 

The hole may be able to pass air, but may be restricted in size...... and it costs nothing to try.

So even if you have an exact replica of the correct tank built you need a cert? Sounds expensive 😞

 

Hopefully you can find a genuine tank in good condition 👍
 

This the set up you are supposed to have?

 

http://www.t85q.com/urTfa/Subgroups/fuel.html

Edited 28 May, 20224 yr by cheezemonkhai

Yeah this one.

http://www.t85q.com/urTfa/Subgroups/fuel-filer/image001.gif

It's not hard to get the tank out. Boot carpets out, remove 4 big bolts and the tank is loose, disconnect the feed pipe to the fuel pump (which is under the car). disconnect vent tube and sender, pull the rubber boot out around the filler.

 

The hardest (smelliest) bit is draining it. Just knowing how much is in there and having a big enough container

Might get a small pump, and pump it out, I can pop the fuel gauge sender out for easy access as I have a new O-ring to fit on that anyway.

Much more controlled than pulling the 15mm pipe off the bottom and it gushing out everywhere.

 

 

On 28/05/2022 at 22:00, RobClubley said:

Yeah this one.

http://www.t85q.com/urTfa/Subgroups/fuel-filer/image001.gif

It's not hard to get the tank out. Boot carpets out, remove 4 big bolts and the tank is loose, disconnect the feed pipe to the fuel pump (which is under the car). disconnect vent tube and sender, pull the rubber boot out around the filler.

 

The hardest (smelliest) bit is draining it. Just knowing how much is in there and having a big enough container

Might get a small pump, and pump it out, I can pop the fuel gauge sender out for easy access as I have a new O-ring to fit on that anyway.

Much more controlled than pulling the 15mm pipe off the bottom and it gushing out everywhere.

 

 

Hi Rob, re. dropping off the 15mm fuel line - I did that once while marshalling on the Mobil economy run, (when all NZ motorsport was cancelled in 1974) -  I ended up looking and smelling like a monk about to self-imolate!

Yay all washers working. As always it turned into a more complex job than expected. The rear washer I had to extend the pipe as it seems to have shrunk with age and wouldn’t reach the pump. The fronts were blocked, and the water smelled funky. It seems to have dried out at some point and formed smelly black slime which has blocked the squirters. Took them off and soaked them in cleaning solution overnight. Had to pull the bottle out and clean it, using bleach to make sure!
And I managed to damage the wiring to the pump so had to repair that too.
It’s never simple!

 

Saw this on your Instagram. Good work!

2 hours ago, RobClubley said:

The fronts were blocked, and the water smelled funky. It seems to have dried out at some point and formed smelly black slime which has blocked the squirters.

I suspect that some 'sole had used a washing up liquid in the screen wash bottle.

Some clips of Rusty from Wookies
https://www.youtube.com/watch?v=X7u4lj5iG2s

Edited 5 June, 20223 yr by RobClubley

 

New brake pressure switches from Latvia

 

 

Bah, it's never easy. That bottom one (right side on pic) was pretty grotty and leaking.

 

 

 

 

 

At least you can get your parts locally🤣🤣

8 hours ago, RobClubley said:

 

 

Is it an optical illusion, or is the thread finer on the new one?

 

Gaz

3 hours ago, Gaz said:

 

Is it an optical illusion, or is the thread finer on the new one?

 

Gaz

 

They are the two old ones. Different part numbers with different threads. 

Ah, righty ho, I was reading it as old and new.  Will get back in my box.

 

Gaz

This is fun and the brake test is very unexpected, at least by me

 

 

 

1 hour ago, Lady Elanore said:

This is fun and the brake test is very unexpected, at least by me

 

 

 

 

Nice! The noise from the rally car!!