Gas Tank Issues

[unstable]

I hate to have two threads open at the same time but they are seperate questions.

I had a gas leak somewhere, plus the fuel filter looked like it came off of the titanic...unfortunately all of the lines did too. I figured that I would try being proactive instead of reactive and I would just replace all of the nasty lines in one fail swoop and get it done and over with...

I had no clean looking line that was accessible as I traced it back. It looked like the fuel filter-->TO-->TBI was a braided steel type line. Not sure if this is OEM or not...but GAS TANK--->TO-->FUEL FILTER = FUBAR.

I dropped the tank today and all of the hardlines coming out of the sending unit are pretty nasty...like...there was no way on gods green earth that I would have been able to disconnect the fittings had I tried...everything just snapped...No big deal there, but I'm figuring that this has got to be semi-common, especially in coastal areas...What should I do about the sending unit? Any way of salvaging it or should I just try to buy new? I wonder if the sending units are the same between the 1500/2500/3500's between 88-98 or whatever the year span is...maybe I could just jack another tank from the junk yard with the sending unit?

Are the fuel pumps the same for the 5.7's and 7.4s?
ACCKCKCKCKCKCKC

maybe it's time to just carburate.

 

[unstable]

Tank is down, pictures are posted. Hope this helps someone...I would imagine that this is the area of the tank that probably rots out first on quite a few trucks...Everything else is solid. I did the screwdriver test all throughout.

a couple of questions
1-First and most importantly...I want to replace these fuel lines and I was expecting a normal 45 degree flare on the ends of the lines but instead I get the garbage posted in the picture below...will a normal 45 degree flare hold?

2-On the opposite side of the steel line going to the sending unit, it's a one piece steel-to-rubber deal...will hose and hose clamps be sufficient on the TBI system? It generates what, 15 PSI on the top end? I'm just not sure how much pressure fuel hose with clamps can sustain. Do I need to used a barbed fitting or something? Typically I just flare a piece of steel line and push the hose over it and clamp it.

3-I'm not sure if it's in the haynes manual or not...BUT, when I was dropping the tank, the lines were so rotted at the sending unit that they broke and I was't able to see what was what...based on my picture can you tell me which is the feed, return and one is for the evaporative stuff...right? it looks like it runs up to the charcoal filter...

4-LAST...I know it's not very environmentally nice, but do I really need to run that line back to the charcoal filter...I mean, assuming that this is an "off road vehicle".

thank you for the insight.

 

[unstable]

Yesterday I ripped the lines out, leaving just the braided steel lines from the TBI in place. I did the screwdriver test on the tank and I found the leaks on top as noted earlier. I sanded her down pretty well and hit her with some phosphoric acid / naval jelly type stuff...rinsed that off and did a gas-tank epoxy repair on the areas that I found that were rotted out. I contemplated getting a piece of sheetmetal and doing a jb-weld over the top of the holes as well but maybe in the future I will just invest in a fuel cell or something...I think the epoxy will be fine for the time being. The pain in the butt part is dealing with the lines and the frozen bolts to drop the tank.

I picked up the two fuel line repair pieces I needed from NAPA...that stupid nipple thing with the o-ring on it...They come with compression fittings but I'm doing SAE flares with unions in lieu of the compression fitting crap. I got home a little late so I only had time to bend the return line and I primed and painted it while I was at it...Hoping that by doing this that I won't have to replace lines anytime in the forseeable future.

I noticed today while browsing ebay that I could have gotten a new tank shipped to my front door for under $100...for the effort I put in yesterday cleaning up the old tank and repairing the holes, it would have probably been worth it...but a little scrubbing always feels rewarding to me for some reason.

Maybe with some luck I will get her back together tomorrow evening. A nice benefit would be that she runs like a champ with the new fuel filter and she's more responsive...if not, I'm going to lean toward a theory that my old shop teacher had that it might be the throttle position sensor being worn out for the number of miles on the rig.

 

[Mike]

I was gonna say it would probably be less effort to go with a new tank and pump. But good work its amazing how the salt can eat this stuff up!

 

[unstable]

You're absolutely right that it would have made more sense to just get a new tank, or at least one in better shape from the yard...In fact, I'm planning on ripping a rear-end out of a 92 1/2 ton this weekend and it would have been a perfect opportunity....BUUUUT, I have the tendency of doing things the hard way. I accidentally stumbled upon a replacement tank on Ebay for $90 shipped...the thing is, I figured I could get off cheaper doing a repair and in the future I might end up doing a fuel cell or something situated over the rear-axle for some weight who knows though...

Today it was raining when I came home and I desperately need to clean out the garage, but I can't do that without a pickup truck and a dump sticker...I now have both send/bypass lines bent, flared etc. and while they aren't perfect, I'm pretty happy with how they came out. I did flares in lieu of the compression fittings, cleaned up the line and primed/painted it.

I was planning on using the dremel to clean up the ends of the sending unit and the threads on the braided lines to/from TBI unit but apparently my dremel got wet and i decided it would be a smart thing to let it dry out before I try using it.

Not sure if I mentioned it, but in the process of removing the rear-most bolt that secures the tank straps, the cage broke on the nut and it was just spinning freely...I ended up using the sawzall to get it off...so now I'm in a predicament where I need to find a way of securing the rear strap. I picked up some hardware and I think what I'm going to do is drop a bolt in from the top and see if I can't weld it to that cross-sill...I just have to be careful that it doesn't cause any interference with the tank...I still haven't decided what to do here but I'm hoping (weather permitting) that I might be able to wrap this job up tomorrow evening.

 

[unstable]

Of course it just keeps getting better....guess I could look at it from another perspective and say "I'm glad it happened in the driveway while I was working instead of...."

I cleaned up the braided steel lines fittings, popped in the steel lines and put the sending unit back in the tank...
I welded a washer to a nut and i was able to toss that up into the cross-sill where the strap bolts thread into...decided to tack-weld it in place through the little recess...
Everything is looking happy.

i go to put the tank up just as i'm losing light. Somehow I manage to get her up into place and I get the forward strap tightened and I realize the bolt I purchased for the rear strap is too short. Luckily I happened to have a stud that I figured would suffice for the time being...hell, it's been nearly a week that this thing has been sitting in the driveway, I want to drive it! So I manage to get the nut started onto the stud and I start cranking down on her...and POW! the rear strap breaks. Again, I should be entirely grateful that this happened while I was working on it instead of when I was driving down the road because that would have sucked MUCHO $hit!!!

nonetheless, I still need to connect the filler tube and that vent...i tried cranking her over a few times but I imagine the lines are completely dry and it will take a bit of priming to get it started and flowing. Bummer...another day in the life of.