cfair

Chasing a squeak today, I took a shot at isolating the gas tank from the trunk to reduce metal-on-metal squeaking. Olds seems to have used felt on wagon interiors, and maybe rubber on underhung tanks like mine. I had some 1/4" thick foam around so I took an hour to slip 2 strips on top of the tank. The tank is roughly 35" long X 30" wide, though I'm guessing someone here has more exact dimensions.

By dropping the tank not off, but down to the lower end of the strap bolts, I used a fish tape to pull 2 strips of 4" wide closed cell foam insulation between the tank & the underside of the trunk floor to stop metal-on-metal squeaking. The foam pulled in quite nicely, but it didn't stop the squeak.

The main thing to document here is that my tank strap bolts were 3.5" long 3/8's-16 carriage bolts that slip up into slots on the underside of the trunk floor. I thought maybe they were 5/16"'s, but no. My old (possibly original?) bolts were semi-stripped from the tank moving around and one was bent. Also one side was clearly tighter than the other, so while I didn't kill the squeak, I feel a lot better about new tight bolts holding the tank where it ought to be.

Before installing I looked at the factory assembly manual. The sequence for 66 big car tank bolts is as follows from top down: carriage bolt - trunk slot - washer - upper nut - tank strap - washer - lower nut. My car was missing the upper washer & nut which secure the carriage bolt to the car, so adding that makes me feel like things will be more solid from here on.

On to the next squeak source...

Chris