Fuel tank rust

[RolfA]

What to use to get the f*****g rust out of my fuel tank? Citric acid? RolfA

[RolfA]

Ok, here's the story. I have been restoring my Dexta. She has been stored outside the past year or so. Finally got her together with brand new fuel/primer tap new filters among other things. Bled the fuel system and she fired up with lots of smoke. Hunting like hell at all revs. Checked the diaphram and it had a 1cm rip. Replaced it. Still haunting and lots of white smoke. Pulled out the oil stick and found out that the primer pump was leaking diesel into the intake and down into the crankcase. DAMN!!! Almost twice the amount of "oil". Disconnected the primer pipe and plugged it until i recieve a extra in line fuel tap. The white smoke disappeared, but still hunting. Lift pump is new. I also checked the fuel tank and there were LOTS of gunk and rust in it. I'm suspecting that this is the hunting problem. Fuel starvation. What can i use to remove this? Pardon my french. I'm 49 yo and writing english is a bit difficult after all these year without school.

[blackbob]

I hope you was joking about using acid

I had this problem with a combine.. Although it didn't hunt, but would just stop, and you had to unscrew the tap on the bottom of the tank and clean the little plastic mesh filter with one hand, whilst the other thumb was keeping the diesel in the tank.. Luckily a Perkins is easy to bleed..
Before the next harvest I took the tank off and took it somewhere and steam-cleaned it out, it was surprising the amount of muck that was in there. You should be able to get your lance in the filler cap, preferably with the tank held upside down somehow. I suppose you could do it with the tank in situ, and with a cold-water washer and detergent and just remove the tap off the bottom of the tank, but I used a steamer.
Consider warming it somehow when you've finished, to remove the last of the moisture, perhaps keeping it in the house a day or two, or using a hair-drier. I don't know your wife

[RolfA]

The tank is off and i have used the garden hose to get the gunk and loose bits out. Still a good amount of stuck rust at the bottom. Citric acid is a mild acid used in food like pickles, jam and fish dishes. Even in coca cola... But if you mix it really "hard" you can use it to remove rust.

[blackbob]

Of course, you are right, I remember now reading about someone on the Nuffield/Leyland forum washing his bits like that

[ianpdexta]

Slosh is good for fuel tanks, there is another similar product but I can't remember it's name. With slosh the instructions say remove tank, put small chippings or similar in the tank, shake it around holding it at all different angles, wash it all out (very important) then some cleaning steps, then use the slosh, again tipping the tank around all angles so the liquid covers all of the internal surfaces. when it sets you have smooth interior, rust is held and pin holes are sealed. I Used it and I would recommend it.

Regards

Ian

[oehrick]

Hi Rolfa

Citric acid is good for copper / brass / bronze cleaning (and limescale) but not so good for iron rust - phosphoric acid* is good for that and changes any remaining rust to a different oxide which is not so reactive.

If there is oily / greasy residue still in the tank and steam cleaning does not shift it all then hot washing soda (or if that fails caustic soda but not very concentrated and wear full protective gear as it burns !) and some lengths of chain or nuts & bolts or even a few handfulls of sharp stones and shake & roll about so they abrade the rust off the inside. (I use a soft wood peg screwed into the fuel tap hole to protect the thread and a bit of plastic bag before fitting the filler cap and shaking, the hot water will heat and expand the air when first shaken and it will try and spit whatever you have inside at you under pressure)

Rinse all the small stuff out well with clean hot water

A hot air gun is good if the hairdryer is 'not available' just get all the moisture out and when completely dry seal with 'slosh' as suggested or other sealer - I have used several coats of diluted Hammerite paint with good results.

Good luck and keep us posted

* I've seen it advertised as aluminium wheel cleaner or cement stain cleaner - depends where in the world you are located

[RolfA]

Thanks for both tips. Probably try out citric acid first. I have some old rusty bolts i a container right now. Need to find the right mixture

[oehrick]

Better than Citric acid is a saturated solution of Salt (NaCl) in Vinegar (i.e. more salt than will dissolve in the Vinegar)

Or better, fill the tank with water with a few spoonfulls of washing soda dissolved then connect the outside of the tank to a 6 or 12 V battery charger negative connection next dangle a chunk of iron or steel into the solution through the filler (insulated from the tank) as an anode, connected to the negative lead = switch on and let it 'cook' for a few hours, rinse out and cook again if rust remains - THE GAS GENERATED IS HYDROGEN AND OXYGEN, DO NOT ALLOW SPARKS OR FLAMES NEAR IT OR YOU WILL MAKE WATER IN THE EXPLOSION

I've been using this electrolytic method of rust removal more and more and if done outdoors the gas dissipates without causing any risk but the rust needs to be dry and not oily.

[RolfA]

Been thinking about that too. But what about the alloy fuel tap threads?

[oehrick]

I suggested using a wooden peg in place of the fuel tap in the previous posting to protect the thread in the tank and would do so for this - not sure if it is an aluminium or zinc alloy used for the tap, neither of which are good with caustic solutions and I have no experience or idea how they would react to the electrolysis.

It is really only the bore of the tap up to the valve exposed so probably not much damage likely but whatever method you eventually use there will probably be an appreciable weight with the liquid - my experience was it is awkward enough to slosh the liquid around so get rid of the tap first to avoid the risk of snapping or bending it

[RolfA]

Citric acid 50 grams per liter warm water removed all the rust. 36 hours. Pressure washer. Flush out the remaining water with diesel. Some black metal where the rust had been but rust free She runs great again. NO hunting after 20 sec from cold Gonna put som Alron diesel additive in each time i fill up the tank to prevent diesel bugs and to keep the system clean. Beer time

[oehrick]

Congrats Rolf - praps I ought to be more adventurous with the citric acid

[RolfA]

Must say that i've removed a good pint of gunk from the tank and replaced two fuel pipes that i suspect sucking air in the system.....