Starting my Tanks Inc install and already hit a snag. Rear bolts on tank straps just spin and won’t come out. Guessing there are welded nuts up in there that are spinning but can’t see them. Any suggestions on how to proceed? For those looking at the Tanks setup, it appears to be very high quality.

 

It’s been a long time since I fought this fight but there is a “speed nut” on a steel tab on each of the 2 large tank bolts. Seems to me you may be able to lock a vice grip on the nut to either limit spin or go 90* to clamp it to the tab. Use penetrating lube & work the bolts both directions to help get things spinning. There may be stripped threads in which case prying on the threaded side of the nut with a screwdriver while turning the bolt may get threads caught & get it moving down the threads. I wish my car was in the air so I could confirm details but it’s not.

Alternative is to cut the bolts off as close to the upper tabs/clips as you can get, that way you can mangle the clips off & hopefully the remaining bolt is short enough to be worked through the hole. A die grinder would make quick work here & get you right up by the tab but you have to control the sparks with a welding blanket and/ or a partner misting the region w/ a spray bottle, a sawzall is safer but access/clearance/angle will not be as good. New bolts & nuts would be required & are commonly available from resto suppliers. If you have new straps with the tank, simply cut the straps, drop the tank & deal with the hardware with much better visibility & access.

Although its 50 years late, anti seize the bolts when reinstalled so they spin freely on new or cleaned up threads & will come off nice & easy if you pull tank in the future even if car is unlikely to see wet weather.

Link to thread on removal/reinstall tips-

https://classicoldsmobile.com/forums...s-tank-120243/

I hope this is info you are looking for and is helpful.

 

If you can't get them loose maybe cut them with bolt cutters, no sparks that way. I'm pretty sure the bolts are available new.

 

My issue is the rear (small) bolts. They spin fine but won’t come out. Bolt cutter would not help as that would eliminate my ability to turn the bolt. There must be a nut inside the trunk pan that was originally welded in place or something.

 

I just swapped out the gas tank in my '72 Cutlass convertible. The smaller, rear bolts are not fully threaded; only the first 1/2-3/4" of the bolt has threads, there are no threads nearer the head of the bolt. To get them out, I used a large flat-blade screw driver to apply pressure behind the screw as I turned the head with a ratchet until the threads "caught" and the bolt screwed out. I have a Texas car so the rust factor is pretty minimal; if your car has spent it's life in the rust-belt, you may have more difficulty with my approach and cutting may be your best option.

Rodney

 

^^^THIS. If you are talking about the small sheet metal screws that secure the strap where it loops around the anchor on the trunk floor, these were typically driven until the last thread under the head stripped (DESPITE the notation in the assembly manual drawing that says "fully seated, not stripped"). Once that last thread strips, there's nothing to grab to unscrew them. As noted, use a flat blade screwdriver under the head, which will pull the screw down until the remaining good threads can bite and then you can start to unscrew them.

 

Thanks Rodney. The “nut” is just a tapped hole on fold of strap. So easy sometimes when you actually know what you are doing (with an emphasis on sometimes).

 

I just ran into the same problem. I just cut through middle of bolts. Now you can replace tank or straps.I now plan on replacing everything fuel related. Go to fusick automotive for your Oldsmobile parts.
btw, I have been going to Weiland since they opened.
take care, Tim

 

Wieland Automotive in Buffalo?

 

Yes, I use to go to holiday olds through out the nineties.

 

Small world. My uncle owns Wieland Auto.

 

Then take all your car repairs to him!!
btw, what are you working on?

 

Too bad I’m in Colorado Springs. I have a ‘68 442. My profile pic is one of the 442s my father drag raced at Lancaster back in the day. Just wrapping up the E85 conversion so I can run the high compression 455 I got without using race gas. Car was such a dog when I got it since I’m at 7000 feet but now is running strong!

 

Tim by chance are you the guy that has the silver 442, ‘70 or ‘71? I remember seeing pics of that car some years ago at Wieland automotive but don’t know who owns it.

 

Yes that is my w-30. Since 1989.
i will send pic when I have better WiFi