Rusty Fuel Tank - Need Help

[Saibbe]

Hi everyone,

I am planning to restore a 1988 e32 730i (m30b30) 5MT that has been sitting under trees since 1995.
It has about 195 000 km ( 121 000 miles), but has been aged due to sitting.

I want to make the engine run, but the fuel tank is actually pretty rusty from the inside. I drained about 10L from it, opened the tank from the top (where the fuel pump is) and took a look.
20170601_184752.jpg20170601_184801.jpg


Does anyone have an idea about how to treat the tank ? sandblasting ? using chemicals ?
The same question goes for the fuel pump that has been sitting in there. Do you think soaking it in chemicals might help to free it ? It certainly is seazed due to humidity.

That you for reading and for your help.

Seb.

[XAlt]

CLR, Muriatic Acid, Coca Cola, Vinegar, etc

[shogun]

Maybe not rust, but bad fuel. Had the same on a car stored for years.
Copied from At Lube-Tech:

Oxidation and Bad Fuel

Specifically, stale gasoline or bad fuel is fuel that has oxidized. Gasoline can begin to degrade and oxidize 30 days after its pumped. During oxidation, fuel molecules become less stable. As fuel oxidizes it can turn to gum and clog jets and other openings in the fuel system, leading to non-starting or poor running conditions. Gummed up carburetors cause serious problems in power equipment that sees intermittent use or long periods of storage.

I removed the tank and made Electrolytic Rust Removal
Google search for: remove rust baking soda battery charger http://www.instructables.com/id/Elec...val-aka-Magic/

[unity]

The problem with that level of rust, is that it may fail. You can do whatever to remove it, but you would certainly need to spray-line it with something. Really, if I had a tank like that I would replace it. My car say for many years and there is zero rust. So you don't need to go new, just find a nice used tank. The pump, I would not bother. Just replace. There are very affordable options for new pumps.

Your next concern would be the metal fuel lines....

By the way, rust in the system can be catastrophic to proper operation. It will quickly clog filters and injectors. As I am sure you can guess.

[Saibbe]

thank you everyone for the replies.

I guess i will give a try to removing the rust with one of the substances you mentionned.

@unity : why should I be that concerned with the metal fuel lines ? Aren't those simply leading to the expansion tank ? I guess that they will de-rust likewise the rest of the tank, otherwise i still have the option to swap it with a healty one.

[shogun]

Here I how I did it with my Highline tank
first washing https://www.youtube.com/watch?v=gw7tCiw6B_s
then electrolytic rust removal https://www.youtube.com/watch?v=rz5C3KRmwHg
worked well

[unity]

If the tank is that rusty, there had to have been water in it. If there was water I the tank before being parked, then it would have easily been pumped into the lines. There are numerous metal fuel lines.

[Saibbe]

Very interesting videos, shogun. So the - is connected to the steel bar, and + grounding the tank ?

@unity well i dont think that the rest of the fuel system is damaged, as when i removed the fuel lines on top of the pump, the gas was still lightly yellow / clear unlinke the old rusty amber gas in the tank that rather looks like a 30-year-old whisky. I guess that in 22 years , water or not, the tank has had the time to rust that far.

[6erWEBB]

So something to think about is all the chemicals that will get rid of the rust but what you may not be thinking about is that the rust used to be the metal of the tank. So, the tank has oxidized over time, meaning its given part of its own makeup to be this new "rusty" substance, so. what youll end up with after you remove the rust is a THINNER tank holding your gas... which isnt great. So, try it, coat it, but... finding a new tank is easier and cheaper

[Saibbe]

@6erWebb : Hello there. I have thought about that, that's why i will make sure that the tank is rigid enough after repair before mounting it back onto the car, otherwise getting a healthy tank still is a better solution. Thank you for helping

[shogun]

Very interesting videos, shogun. So the - is connected to the steel bar, and + grounding the tank ?

More info http://myweb.tiscali.co.uk/andyspatch/rust.htm
http://www.secondchancegarage.com/pu...cleaning-1.cfm
google for: electrolytic rust removal

[328iFun]

Just get another tank

Sent from my SAMSUNG-SM-G935A using Tapatalk

[dimonlexx]

You can use e34 plastik tank. The biggest is 90 liters as the smallest for e32. Just some simple modifications and you will have new tank.

[SergeBMW]

New tanks cost upwards of $750 and used ones are nearly impossible to find. Erich, did you just use a battery charger for the power source? I can set mine to 2A which is used for trickle charge. That should be fine considering the size of the tank.

Other than that, I was looking at the muriatic acid technique as well, but id have to make sure to neutralize it before pouring out, the part that worries me.

[Sansouci]

You can probably find shops that do tank restoration which may be a cheaper solution. If they are honest, they will tell you whether it is worth it or not.

[shogun]

Erich, did you just use a battery charger for the power source? I can set mine to 2A which is used for trickle charge. That should be fine considering the size of the tank.

yes, I used a battery charger. But most of the stuff which we first thought is rust was actually degraded gasoline, which turned to red color gums.
Use google search for: rust removal baking soda electrolysis, or rust removal washing soda electrolysis, you find a lot of info
http://www.instructables.com/id/Elec...val-aka-Magic/
https://www.spaco.org/Blacksmithing/...ashingSoda.htm

of course a pro shop that does tank restoration whill probably make it perfect.

[SergeBMW]

yes, I used a battery charger. But most of the stuff which we first thought is rust was actually degraded gasoline, which turned to red color gums.
Use google search for: rust removal baking soda electrolysis, or rust removal washing soda electrolysis, you find a lot of info
http://www.instructables.com/id/Elec...val-aka-Magic/
https://www.spaco.org/Blacksmithing/...ashingSoda.htm

of course a pro shop that does tank restoration whill probably make it perfect.

You may be right on that, I had the same feeling about the rust which might be mostly degraded fuel. I will drop the tank and pressure wash it first to see what I am working with. The car sat for 2 years before I purchased it.

[shogun]

In the E34 for sale/classifieds section someone is planing to part an E32 750iL from 1989, tell him what you need, see the thread Feeler-E32-750il

[SergeBMW]

In the E34 for sale/classifieds section someone is planing to part an E32 750iL from 1989, tell him what you need, see the thread Feeler-E32-750il

Thanks! I would have never checked there! I just posted, hope he is willing to part those out for me.