Rusty Fuel Tank Tab Repair

Shit, Had I known there were options I would have tried one of them.

But, I ended up buying a new OEM tank from GM at a cost of about $500.00. I already had a new OEM Delco pump assembly that I bought some years ago on an Ebay auction for $75.00 shipped.

The rest was a shit load of labor to replace the tank assembly. The whole rear cradle came down to accomidate the replacement. By the time it was all done it cost about $1,000.00 to eliminate the CEL for a Evap Leak.

In this State I couldn't get an inspection sticker without eliminating the Evap System leak which was coming from the top of the fuel tank at the fuel pump flange. When the tank was removed it was obvious where the vapor leak was.

But, I already knew where the leak was from using a smoke machine on the fuel system and it came out at the flange of the fuel pump. After pulling the inspection plate it was quite obvious that everything was rotted to the point of no return, so I ordered a new tank from GM.

EDIT: The tank cost included new tank straps, a retaining ring, fuel pump seal and shipping came out to less than $500.00.
Add the cost of a new OEM fuel pump, that I had already bought real cheap (didn't need the new pump, but figured I'd use it since we were going to take the tank out) and then I paid a local mech/friend of mine $400.00 to do the job for me due to my back not being in great shape and I came out under $1000.00.
If you are going to do the mechanical work yourself it will obviously be a lot cheaper.

I never thought of asking the body shop I do business with what they can get a new tank for. I just ordered it from Monsterparts.com when they were still in business after I looked on-line for any other source and talking to my local parts stores. When the other sources came up dry I pulled the trigger and bought from Monster.

Hey guys,

I'm going to dig into my fuel tank tomorrow night and I know for a fact my tabs on my gas tank are toasted. The lock ring is almost dust too, and it's causing fuel leakage when the tank is full/nearly full. So I've decided to go with the method that Larry posted midway through this page and use bigger stainless steel screws and washers to hold down a new lock ring I bought.

I'm going to clean up the rusted fuel tank ring as best as possible, smooth it out, and paint it with POR-15. Hopefully that will dry by morning (the morning of the meet) and i can put in a new tank seal and screw down the new lock ring into the tank.

Anyone have any other suggestions? Thank you.

Z-type wrote:

I'm going to clean up the rusted fuel tank ring as best as possible... ...Anyone have any other suggestions? Thank you.

I know you want to dig into this tomorrow, but do yourself a favor and just order a new ring. They come not rusted and pre-painted and they're cheap.

http://www.amazon.com/gp/product/B000C9SNLC?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00

Oh, I meant the metal on the fuel tank where the tabs used to be. I have a new lock ring .

Oh well in that case my only suggestion is to get some airflow going in the trunk, work in the coolest place possible. It gets pretty hot while you're jammed in there hammering away at that dirty ring . That and the fuel vapors get to you pretty quickly. A mask might even be beneficial.

Here is my old lock ring. I think.


And what I was left with after that was all gone. Only 3 tabs that were recognizable and none of them were solid. They were all flaky too. They're still there and usable enough that I could use them to help position the new lock ring.


New unit on the left. Got a good price on it. New pump, housing, internal filter, and the improved design fuel level sender.


Updated wiring harness that had to be spliced in - easy. They even gave diagrams because some wires were different colors.


And here is the fix I came up with based on a suggestion earlier in this thread. Stainless self-tapping screws and washers.



So normally I would have just gotten a new level sender and separate fuel pump to fix those problems, but the other problem I was having was the non-existant lock ring. It was no longer holding anything down so I got fuel leakage pretty bad when the tank was full. If I filled up the tank too much, gas poured out everywhere. So I just got an entire new sending unit to get the pump, level sender, and gasket for the tank opening.

Got it all together the first time and fuel was still leaking everywhere from the tank opening under the sending unit. I was not pleased. I took it apart and realized the inner sealing surface for the gasket on the tank was warped slightly here and there, which I have not heard of before.

I didn't have much of a choice what to do, so I used a sealant. Permatex 85420 - fuel resistant. Not affected by fuel unless it's submerged for long periods of time, which this ring area never will be. Put a good bead under the gasket ring, and on top for between it and the sending unit, used it to seal the screws for the lock ring, and let it sit overnight. Fired the car up today and drove it around some hills and turns and it's still bone dry. I'm hoping it holds up!


I hope this information and pictures helps anyone else with no more lock ring tabs on the tank...

Thanks to everyone who participated in this discussion. With the information gleaned here and also seeing what's out there today, in 2021, I believe I have solved the fuel leak at the tank pump/sender. This keeps my 1997 Riviera, which I bought new, on the road indefinitely.