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1978 k20 pickup dual tank replacement

RootBreaker

RootBreaker

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Ok so first the story...
I have had my truck since 1989... many body swaps, motors, etc... HOWEVER the dual tanks have followed through the years.
few years ago I emptied some crappy fuel mixed with motor oil and figured id run the truck BUT never did. Thus truck sat for 3 years with that fuel. I am now running it and trying to get rid of it.

interesting...
I emptied the left tank, cleaned it out - was some rocks, pull tabs (most of you youngins dont know what that is) and other stuff.. but nice and clean.. plus fresh fuel...
so I just drove the truck to work (130 miles round trip) on the crap tank and clogged my fuel filter on this fuel. I figured @ 10mpg only gallons max left. my fuel gauge still read past F so I figured the float is stuck or bad... cmon it is 38 years old..

so I got under the truck 2 weeks ago... put a fuel filter in front of my fuel pump that has a proprietary fuel filter to pre filter the gunk and drain the tank. I got about 7 gallons so yeah tank is empty. HOWEVER while putting the extra filter in i ummmm cut myself with a new razor blade thus 4 stitches. I didnt swipe cut just rock on the fuel line so when it went through it just tapped my thumb knuckle... sucked... so now stitches are out and I can continue to work on the truck.

I just went under and pulled 7 of the 8 bolts. Went for the 8th and the tank rocked hard and fast on a angle... i pushed on it and something wasnt right... so I got my neighbor. he held one end and I removed the other bolt... and dropped the tank.... yes literally dropped the tank. CRAP.
so tank is down AND IS FULL!!!! 18 gallons smack on my arm, slammed my elbow, bleeding, etc... GRRRRRRRR

so now I have beer to numb stuff up. when the tank dropped it slammed and got a tiny dent BUT created a hole. So this means the tank was very rusted and getting ready to leak in a few years anyway.

so I emptied the tank and man their is some gunk in it. even around the float, pulled that out and reached in and the upper part of the tank has so much rust deposits on it.

now this brings up another few issues..
1. my dual tank solendoid isnt working so it is bad.
2. fuel filter clogged and I thought it was on the junk fuel tank but isnt. It is on the clean tank thus it is rusted too...


so now lets get to business....

I have dual tanks. switch works, wires work...

what I am thinking is a few things...
  • Replace both tanks
  • Replace all 4 tank strap
  • Replace dual tank solenoid
  • Replace ALL fuel lines Metal and Rubber

so Q 1.... With replacing all that.. would you replace the float assembly? why still use old parts in a new setup?
so next... I started googling and it is interesting. i have the dual saddlebags and I see different things.
I thought I have always had 18 gallon tanks but all I am finding is 16 gallon and 20 gallons so will definitely go 20 gallon and need to get the correct floats...

In addition to size difference in tanks I am also seeing some say in front of rear axle and some say side tank... but they are different websites... SO... have you bought anything lately and what do you recommend?


i see the straps are like $26 per set and tanks can be $80 so I see 20 gallon tanks with straps for $100...

so I am thinking the following... help correct me if I am wrong...

Tanks - dont say left and right
1978 Chevy K20 Truck 20 Gallon Fuel Tank With Strap Set Carbureted With 8 Foot Bed
$101 http://www.1aauto.com/fuel-tank-with-strap-set/i/1afrk00019?f=445525&y=1978

Float assembly - 3 outlets
1aauto.com shows a different one for left and right and it is double the price!!!!!
but this site doesnt say so. Also doesnt say tank size matters... everything I find elsewhere no one states left and right so im thinking one works for both???
Would this work????
$31 http://www.autopartswarehouse.com/s.../1978/Scottsdale/8_Cyl_5-dot-7L/SPIFG05C.html

or should I go with these
$50 http://www.1aauto.com/search?partTy...1516&q=fuel+tank&year=1978&abTestingValue=OFF

$77 http://www.1aauto.com/1973-79-fuel-...k-with-3-outlets/i/1afsu00031?f=446150&y=1978



$58 Dual Tank Selector Valve
ac delco 467513
http://www.godrules.net/opencart/acdelco-467513-fuel-tank-selector-valve-automotive



Ebay -
$94 free shipping per 20g tank with straps
http://www.ebay.com/itm/Fuel-Gas-Tank-20-Gallon-Straps-Support-Set-Kit-for-Chevy-GMC-C-K-Pickup-Truck-/310900530748?fits=Year:1978|Make:Chevrolet|Model:K20&hash=item48631d9e3c:g:wIYAAOSwe-FU5adc&vxp=mtr

 
so im finding the dual tank valve is not easy to find anymore... I am finding MANY of the 6 port but with more than 1 wire. Trying to decide what to do here..

All of the 1 wire setups are only 3 port (1 each tank and out to carb). From what I have learned the extra 3 are fuel return lines. Not sure I need these...
Also in my readings the 6 port was for an automatic trans and 3 port for manual. My truck was an automatic but i went manual....

man im more lost than ever. guess I need to buy the one I linked above and just replace what is there...
 
Ok I'm a little confused on what you got going but here is my knowledge on it. Shortbed trucks got 16 gallon tanks and longbed trucks got 20 gallon tanks. Certain yrs I believe were the same left and right. I don't know what yr your truck is but my old '79 had 3 outlet senders and I bought new ones from my local napa for both sides. Mine had a 3 port selector valve. This was for suction lines only. Since there was no return line coming back off the mechanical fuel pump on the engine. I believe they were built both ways(with and without) return line on the pump. Not sure why. I always replace tanks with the poly ones just so I never have to deal with rusty tanks again. My '79 had mint condition tanks so I just replaced selector(found a 3 port from CARQUEST with 1 wire) and both senders and it was good. If I needed to do a tank or both I was going to convert to a single 31 gallon blazer tank in the rear. Doesn't look too hard if you google it.
 
hmmmm maybe a 31 gallon blazer tank is where I should be looking...

so my truck is with the return line.

Currently my truck has 3 ports on the float assembly.
1 goes to selector valve top
1 goes to selector valve bottom
1 just has a 1" breather line

id have to figure out where to put the 31 gallon tank in my truck.. getting rid of the side saddle bags also means if I put a BL back on the truck (I know most dont like BL but I had a 3" and it served its purpose) i wouldnt need to build protection bars (required in NJ - and i know NJ sucks - another topic)

I have no clue when it comes to this stuff... my father said the obvious ( make sure im getting power to the 12v post) so need to check that first.
then second he told me there was one in the toolbox he gave me. Hope i didnt throw it out.. ughhhh if so I may just bite the $70 and buy the one I found as it is a drop in and go...

or hold off and save that coin for the blazer conversion - off to searching this site now for that... hah

google image got me this....

PICT0016-1.jpg


from here
http://www.barthmobile.com/eve/forums/a/tpc/f/3431087061/m/4303955787
 
oh sheeze.... like for real... why dont I utilize what few brain cells I have left???

Ok so my truck
Was:
automatic
mechanical fuel pump
return line from fuel pump

Now:
manual
electric fuel pump
return line not in use anymore


so with that I can go with a 3 port not worrying about the 6 port anymore!!!! DOH!!!!!

ok...
 
I believe this is the one I used. It would work perfect for your application with no return line needed. If you search google the blazer tank mounts in the rear where the factory spare would be. Need to fab mounts a little but not bad compared to buying two saddle tanks. I didn't really search the center mount 40 gallon tank option at all but I think it has been done. I had a 32 gallon steel tank off of an International medium duty mounted in the bed of one of my old trucks once. It worked good and only took up about 2' square of space in the corner of the bed.
upload_2016-9-6_14-26-33.png
 
ughhhh I think my switch is bad...

at least I have power on the pink/black wire.... and it should be the green wire to the tank and no power when throwing the switch

I know I saw a diagram somewhere.. trying to google it now.. hah
 
Pffft figured it out. Diagram above is wrong... hot in middle but still pink. I took switch out as it looked like switch was bad... jumped pink to green... still no voltage to green wire at valve....

Pulled plug apart at firewall under hood.. voltage there...

So lets backup many years when i was a wee lad... u know.. use wire nuts... butt connectors.. etc... well i have been fixing things as i see them... i even ran the wires in wireloom and fastened to frame with loom connectors...

Jump back to now.. i went to drivers side and saw wires breakout to that sender.. i saw green wire.. tugged on it... wth!!!! Disconnected. Ran through loom... found it. Used butt connector and must not of been a good crimp... so gonna solder wire and shrink tube... but that will have to wait as im at MMA.. well my kid is but im in parking lot.

I still need new tanks but electrical is fixed...
 
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