hi all,

can anyone give me detailed instructions on how to replace the fuel tank? how to disconnect the fuel lines, do i need to disconnect fuses?, fuel pump?, etc. i know it cant be as easy as taking the straps off and dropping the tank....i bought all new sending unit, straps, tank, gasket, nut... i just need to make sure im taking it apart and putting it back together properly.

thanks everyone!!

 

It is just a matter of taking the straps off, dropping the fuel tank and disconnecting the lines. Most likely there are rubber hoses with a clamp. There are no fuel pumps in the tank like newer cars. The fuel pump is bolted to the side of the engine.

The way it should be........

 

Sorry I don't have a direct answer for you, but it sounds like a Chassis Service Manual is something you may want on hand for this project and others.

If you are comfortable with using print outs, go to the 'Wild About Cars' website for a free download of the manual. Here's a direct link to the section you are working on: http://wildaboutcarsonline.com/membe..._Section_8.pdf

 

Really no big deal, as managed to do it on an old Pontiac as a high school kid for the first time, with limited tools. Most important, is draining the tank empty, to keep weight down. Some of the strap bolts may be frozen, and possibly break. Also be prepared to replace some strap isolation rubber. Always a good idea moving some air around with a fan, to help from gas fumes building up.

 

Hardest part is removing the rusty bolts. Lots of penetrating oil a few days before you start and some folks just cut them to avoid the hassle. Good idea on getting all the parts lined up in advance, I would also replace all rubber lines while you are at it since old ones don't like ethanol. A member sells the pad that goes on top of the tank if you do a search, and you might get lucky and find the original build sheet.

 

As others have already said, it pretty much is, with the exception of:

• Make sure the tank is as empty as possible (1 gallon of gas = about 6 pounds),
• Remove the hoses (just cut them with a pair of garden pruners - they'll need to be replaced anyway),
• The bolts will be rusted, and, as H Horns said, a few days of penetrating oil (I like KROIL, myself) will help.

That's really about all there is - remove bolts, tank comes off.

- Eric

 

I've used a 1/4" piece of plywood with my service jack to support the tank during installation. This would be the time to restore the straps. The fuel line spring clamps might need to be replaced.

 

I recently removed my gas tank, cleaned, new fuel sender, and reinstalled.

MAKE SURE YOU PUT A JACKSTAND UNDER THE TANK WHEN YOU CUT THE BOLTS. My bolts were completely rusted out at the threads.

What i did,

Put a jack under the tank/ cut the straps, BAM, tank hit the jack. Lucky i had it there. You'll never be able to get all the gas out of the tank, so as eric said, it'll be pretty heavy.

The way you lower the car from the jack, SLOWLY, and make sure all the hoses/wires and clear so you dont break anything.

You "might" need to jack up the *** end of your car to get the filler neck out.

Best of luck, be safe and dont crush yourself under the car.

 

Pad that goes on top of the tank?

Also what are the strap isolation rubber?

Its these little parts that I dont know about until its down, I just want to have everything right there and then. Nothing frustrates me more than making multiple trips to the parts store during a supposedly quick project...

Anyone have any idea of what size rubber hoses I need?

Thanks all. I will upload photos when I complete it!

 

Yes the pad goes on top of the tank.

Strap isolation rubber is a rubber or coating that goes around the strap to keep it from chafing on the tank and making a hole.

 

Here's a link to the tank pads sold by a member, not sure where else you can get them. Previous owner of my car bought one but did not install it so I put it in when fixing a leaky sender. Don't think the factory used any isolators/padding on the straps and none on my car now. A couple of different size hoses were used for vents/supply so check Chassis Manual for sizes or maybe just take a short section of each to your nearest parts store. Make sure you have the right sender since big blocks have a return line.

https://classicoldsmobile.com/forums...on-item-2.html

 

Thanks Dane!

>Rubber strips/insulation/coating between the straps and tank underside - NOT USED. Factory didn't put anything in there and you don't need to add anything. Once the straps are tightened up there isn't any movement/rubbing between the tank and straps. No risk of rubbing through, etc. I've pulled and have seen a lot of these tanks and not once have I seen any evidence of problems in this area. No need to spend any $ putting anything between the straps and the tank.

>Gas Tank Pad - Your car may or may not have had one from the factory. At some point, Olds stopped installing these on some or all of the cars....sometime after the 1970 model year. Don't know if this was a plant specific deal or something other. I do see them on other GM models such as Grand Prix's as late as 1972 (haven't had the chance to look under any Grand Prix's later than that).

 

The pad would probably be a good idea anyways though right? I mean for $25 bucks... you mind as well do it, ensure no rattling and have a nice snug fit, for the price.


Thanks for all of the advice guys. Really appreciate it. You know you'll be hearing from me more as the projects go on!

Next up, putting on the header back exhaust system (flomaster)

 

I could have swore someone posted a link to a step by step instruction and then when I came back to this post I couldnt find it!

Did anybody else see this?!

 

You may be thinking of the section in the Chassis Manual - I posted the link in a reply above.