This is in regards to the '89 IROC in the sig...

I have been having some problems with fuel leakage from the tank, and I have finally realized that I'm going to need to drop the gas tank to see where the leakage is comming from and to fix it. I'm looking at my Haynes manual in the section for fuel tank removal, and I have some questions before I jump in...

1. I just put in a full tank of 93 octane (wasn't anticipating having to drop the tank). First of all, I don't know what I'm going to drain it into to begin with. Second of all, I don't know how I'm going to get it drained. Lastly, I would *like* to reuse the fuel, if I could. I suppose most of that will depend on what I store the fuel in. Any tips on removing the fuel?

2. The manual says to support the vehicle on jack stands (obviously). I've never seen one of these tanks out of the car before, so I'm wondering just how much height I'm going to need on the car to get it out. Will your typical 3-ton jackstands give enough clearance, or will I be needing more height?

3. The manual says to disconnect the exhaust pipe from the rear of the catalytic converter. Mine appears to be welded on, and I don't have any equipment to weld with (nor the skills). I have a stock single-cat setup; could I just unbolt the exhaust from the exhaust manifolds instead? I'm not really sure how much movement I will be needing from the exhaust...

4. The manual basically says that the whole rear axle will have to come out (and I've never removed one before). It's pretty clear on how to take it out, but I'm worried about putting it back in--those springs look like they're going to be trouble. Will I need spring compressors putting it back in?

I don't really know what to expect once I have the tank out--all I know is that I can smell unburnt fuel from the outside of the car, and that there is a long stain on the tank originating from the top of the tank. Any ideas as to what *might* be the culprit for the leaking so that I can prepare in advance?

Thanks for the help!

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A picture of the leakage:

 

My friend, you are in for one BIG project. Changing the Fbody's fuel tank is quite a task. For starters, can you see up to the lines, and make sure one of them isn't just leaking? If they aren't then you may have a bad seal where the fuel pump goes in to the tank. To drain the gas, you could siphon it out, or you could disconnect your fuel filter, activate your pump, and let it out that way. Be warned, it will SPRAY. Jack stands, in my opinion will give you the clearance you need to do this, but not the clearance to do it comfortably. You have to remove your exhaust, LCA's, and the entire rear end. You will need spring compressors to do this. I really think you would be better off finding someone who has a lift, or taking it to a shop to have it removed, especially if your exhaust is welded. I wish you luck, and I would recommend searching for any details I may have left out, as it's been a while since I've done this.

 

You most likely WONT need spring compressors to remove the rear springs.

0. Drain tank. I had to siphon due to a bad fuel pump, but using the method suggested earlier would also work for you. Be careful though...
0.1 Put the car on jackstands and let the rear hang.
0.2 Remove exhaust from cat->back and all heat shields
1. Remove Torque Arm
2. Remove Driveshaft (fluid will come out of tailshaft, be ready with a cup or a bucket, depending on the angle of the tranny.
3. Remove the swaybar
4. Remove the panhard bar
5. Remove the panhard bar brace
6. Disconnect the rubber brake hose that connects to the steel hard line that goes from front to rear.
7. Support the rear end with a jack
8. Either remove the LCA's, or just unbolt them from the rear
9. Unbolt the shocks from the rear end. be careful doing this, the rear will shift as there will be nothnig supporting it except the jack!
10. Lower the rear end. If the springs havent fallen out by now, they will soon.
11. Remove gas cap door and inner molded plastic
12. Unhook fuel pump power connection
13. Remove the tank straps
14. The tank should come out fairly easily, it will take a bit of twisting, but it'll come out.

If I were to do it over again, I would have gotten a new tank instead of getting mine repaired. My tank lacks certain baffles, so the gas sloshes around a lot If you reuse the old tank, I reccommend sandblasting it before you do anything. The leak on the filler neck causes gas to drip down the side of the tank, causing dust and dirt to CAKE up all over. Its a PAIN to get off, and sand blasting would probably work the best. Pressure wash the tank, then take it to a radiator shop and have them weld the filler neck up. It'll cost about 60 bucks due to the safety precautions that need to be taken when welding gas tanks shut. When you get it back, you can either just slap it back in, or hit it with a few nice coats of paint. Installation is the reverse of removal Hope that helps! If I missed anything, I'm sure you can figure it out. Its not really techincally difficult, its just a PAIN! Oh, and NOW is the time to change the fuel pump. You might as well put a new one in while the tank is out, cause you'll just end up doing it later if you dont!

 

i believe there's a recall on your problem, call a dealer and ask. i have a 12v external eletric fuel pump i connect to a battery to drain gas tanks with. droppingthe gas tank isn't really a bad job, it just sounds liek it. to me the worse part is exhaust system.

 

I had the EXACT same problem that was described in the recall (leaking filler neck), but my VIN was not covered by it

 

This is about the height you need.




You don't have to pull the rear off of the car, but you need to get it as low as possible.
I've dropped 2 tanks and it isn't hard at all, just time consuming.

You don't need spring compressors, rear can stay on the car, removing the muffler makes it easier, but it isn't neccesary.
Tank will come out at a funky angle.

With the rear off and the muffler removed, it will make it really easy to pull out and put in the tank.

 

Wow, thanks for all of the detailed replies! Good stuff...

What I was most worried about was the exhaust, but it looks like you guys think I can leave it up. I'll have to see how far I get with that, but I don't know what I'm going to do if I end up having to drop it since I can't weld. I just need to get the car up on jack stands and see what I'm working with...

RE: The recall... I have checked into it but, like Scott_92RS, my VIN wasn't covered. It doesn't really make sense to me why they cover other cars with the same defect and not mine, but there's no use arguing with GM's database...

Thanks again

BTW -- One more thing... about how much will the tank weight without the fuel in it? Can I guide it down with my hands, or will I need a jack under it?

 

You can guide it with your hands, My tank still had a little fuel in it(siphoning didnt get it all), and it was still fairly light.

Scott

 

One *******IMPORTANT******** detail:

When you have the tank down, replace the fuel pump while you are at it. The way most third-genners luck runs, the fuel pump would die the minute you reinstalled the tank. This could turn a 4-hour job into 8-hours or more. I say just replace the pump while you already have it apart.

Andy

 

Oh, trust me, I'm one step ahead of 'ya about the fuel pump.

I've found an AC/Delco pump at AutoZone for ~$90.00--I'm just hoping that it is a stock replacement for what I've got and that it isn't a remanufactured unit (else I'll be replacing it even sooner).

 

When I dropped my tank to replace the pump, I energized the fuel pump by hooking a long wire from the positive terminal of the battery to the "G" port of the ALDL (the fuel pump was working off and on). I took the fuel pressure gauge off of it's hose (Hypertech gauge with about a 20" hose) and ran the hose from the schrader valve on the fuel rail to a gas can. After the can filled up I would shut off the pump, empty the gas can into another container (like my other two cars tanks) and repeat this untill it was empty.

 

I read a thread earlier about dropping the fuel tank vs. cutting a hole in the floor. After i thought about it i figured i'de just drop the tank because after getting the carpet pulled up, cutting the floor and fuel lines and patching the hole it would take just as long. Heres what i came up with......... Unbolting everything about 1 hour...........wrestling the tank out, cussing and throwing tools around the shop, 3 hours. Installing new pump and having every last bolt in, 38 minutes. Would i cut a hole in it the next time ? .... NO ........ Two words.............. FOR SALE , lots of luck to you.

 

Well, I finally got around to pulling the gas tank today. It took my me and my dad about four to five hours, but we did it. Most of the time was spent just unbolting stuff--and since we're taking this opportunity to fix some other things while we're at it (i.e. squeaking shocks and bad rear brakes), we took more out than we really needed to.

I ended up draining the tank by forcing/hardwiring the fuel pump AFTER I had the tank out because I went through hell trying to figure out how to do it beforehand. Turned out, I was shorting I was using a bad wire to make connections (yes, I actually managed to use a "broken wire" that didn't look broken) . About the only nonstandard thing I had to do was cut the muffler off (since mine was welded in at the cat). I cut it off about 3 inches from the muffler but, looking back, I wish I had cut it near the cat--would have made pulling the tank easier.

I also figured out where the tank was actually leaking: it was leaking from the region where the filler neck connects to the tank (which was originally what I had thought). You can see now how deceptive that first picture was--I could have sworn that the leak was comming from ABOVE the tank when I saw that. I suppose the leaking fuel was just absorbed upward by the dirt.

To fix the tank, I had my radiator repair man (who was cool enough to open up his shop on Saturday just for me) just solder around the neck.

Now I just have to put it all back in...

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<i>Just out of curiousity...</i> Was this exactly the problem that GM responded to with a recall (leaking from where the filler neck meets the tank)?

 

A picture of the tank after it had been repaired (and cleaned)...