M38 Gas Tank

Harsh · Post by **Harsh** » Wed Jan 04, 2017 3:37 pm

I am a little confused by the tank in my M38. It came with it when I bought it, but it is not exactly the same as an original since it does not have a fuel intake system on top of the tank. Does someone know where this comes from.

Here are some pictures of the tank.

4x4M38 · Post by **4x4M38** » Wed Jan 04, 2017 4:31 pm

My first guess is an early repop. Maybe long time green disease
guys can confirm. Were there some early repops without the pickup on top?

Dimensions would help but one question. How does
the filler neck fit in the tub? Also I see some solder near the neck on
top of the tank. Maybe surgery to replace or move the neck on a repop
to fit better?

If it fits and doesn't leak you are ahead of many.

Fixing it to factory is not impossible but will be some work. The filler
attachment ring soldered to the tank has a depression below it in the sheet
to take into account the screws protruding through the ring. Not sure
how you would replicate.

kenperkins · Post by **kenperkins** » Wed Jan 04, 2017 7:38 pm

early md juan from the '80's. I broke the feeder tube off the bottom once on a trail ride

brimac · Post by **brimac** » Wed Jan 04, 2017 8:06 pm

http://www.willysmjeeps.com/v2/modules. ... highlight=

Looks like mine

Post by **wesk** » Wed Jan 04, 2017 10:46 pm

Here's a good comparison:

Large version here:
http://willysmjeeps.com/v2/modules/gall ... risons.jpg

Harsh · Post by **Harsh** » Wed Jan 04, 2017 11:16 pm

Thanks for the information. Clears up a lot of confusion. Now I need to look for an original or exact replication of the tank.

Post by **wesk** » Wed Jan 04, 2017 11:23 pm

MD Juan is the only repop tank manufacturer still making them. They are closer today then the early ones but still not perfect.

There used to be a guy in Big Sky Country fabricating M38 tanks a few years ago.

4x4M38 · Post by **4x4M38** » Thu Jan 05, 2017 8:09 am

Again how does the neck fit in the tub? That is the real problem.
Is the height ok?

You could make a new mounting ring for the pickup and just use
shorter screws. The rear bracket would be easy to make. Soldering
the wire clips on is easy as well.

Factory resto or....

Harsh · Post by **Harsh** » Sat Jan 07, 2017 12:41 pm

The neck fits the tub pretty well and the height looks right. I will keep looking for a tank if possible as the tank is pretty beat up, but if I cant find one, will straighten out the tank and make a new mounting ring as you are recommending.

4x4M38 · Post by **4x4M38** » Sat Jan 07, 2017 2:54 pm

The height and the neck are the two killer problems with repop
tanks. If you don't have these issues and it doesn't leak you are
way ahead of the curve!

ThomasTausend · Post by **ThomasTausend** » Sat Jan 13, 2018 8:21 am

Hi guys,

seems like the M38 I'm restoring right now also has one of these MD Juan repro tanks.

Wanted to clean and seal the inside with a special cleaner/primer kit I bought, but discovered that the inside of my fuel tank is split into 2 fully enclosed chambers, having only two small holes at the bottom for fuel exchange between the chambers (indicated by the red arrows). Notice that the inner wall you're seeing in this picture is towards the inside of the fuel tank. The outer wall of the tank in this pic is on the right handside.

That makes working with my sealing kit impossible I guess, since I wouldn't expect great success for the sluggish paint to flow into the other chamber...

A bit of background on my M38: It was powered by a Mercedes diesel engine using that same fuel tank when I got it. I'm trying to get it as stock as possible with the correct engine, which is already installed. Are stock tanks and/or MD Juan tanks split into chambers or could this have been a mod for the diesel conversion?

Thanks
Thomas

4x4M38 · Post by **4x4M38** » Sat Jan 13, 2018 12:15 pm

Hi Thomas,
Yes the factory tanks and MD Juan tanks have the baffle separating
the tank in two. Besides reducing sloshing it helps keep the fuel pickup
wet when in rough terrain.

You can get access through the fuel sender hole but the fuel pickup hole
is larger. Both are on the other side of the baffle.

ThomasTausend · Post by **ThomasTausend** » Sat Jan 13, 2018 1:10 pm

Hi Brian,

thanks for the quick reply. Nice to hear of any part on my jeep that is somewhat correct

As you can see in my photos I have no fuel pickup at the top nor a hole for the sender unit. Maybe I can use paint thinner to reach the second chamber or I just leave the tanks inside unpainted as it is after using the rust remover fluid.

Is the only reason for the fuel pickup on top of the tank that you can't rip it off in rough terrain? Other than that (and the fact that its not 100% accurate for a M38) I'm good to go with my tank for the technical aspect? I know that I need a fuel filter and want to go with a simple modern in-line filter.

Post by **wesk** » Sat Jan 13, 2018 11:42 pm

If the photos in your post above are of your tank then the top offers 0 access so any attempt to properly flush the tank and apply the proper coating correctly insuring no future peeling and clogging of the filter are not very good. Short of sending your tank to a professional shop for a proper de-rusting and coating I would limit the home remedy to a thorough de-rusting by filling the tank completely with a light weight rust remover or an acid base liquid like coca cola, let her soak a few days and then flush it with gas. Then install it and keep the tank over 3/4 full whenever it is not being used.

The main purpose for the top feed on the military tanks was easy access to the feed and the in tank filter system.

ThomasTausend · Post by **ThomasTausend** » Sun Jan 14, 2018 6:45 am

Thanks Wes!

That's what I'll do for now. Just removing the rust, get the jeep together and save the painting for later. Don't have a fuel sender unit right now, which I will can always add later, cutting a hole and THEN coating the tank. So much else to do right now anyway

Thanks guys for your help, this board is amazing (as well as Mr Millers book on the M38 which was a huge help to me right from the start)!

Thomas