I have a 1922-23 touring body with an oval gas tank under the drivers seat that needs removal. It is attached with 2 straps bolted to the frame rail with castle nuts. The castle nuts are difficult to get to. A socket is out of the question, the round end of the 9/16th wrench won't go on either. The open 9/16th wrench end goes on but its operator does not currently generate enough leverage to get the nut off especially with the cotters still in place.
Is there a trick to getting the castle nuts off? The cotters are very difficult to get off under the circumstances.
You have to pull those cotter pins out of the bolt first, then loosen the bolt...it is a bit of hassle to loosen them, but the only other way to get to them is to remove the front seat box and push to the rear
One band has two mounting bolts whilst the other has only one. And are easier to get to with the front seat removed.
But if the car is upholstered, you'll have to undo the arm rests so you can get to the screws along the side of the front back rest on either side on the car...the four screws in the seat box are attached to the brackets that mount to the frame walls and there are two flange screws that screw into the front part of the body rails and there are 4 screws that screw into the sides of the rails behind the seat box that anchor the kick panel at the back of the seat.
They are fairly hard to get to. If you want to save the nuts and bolts you will need to remove the cotter pins. If they are rusted up and seized you can use a lot of WD-40 to maybe help loosen things up.
You can use a ratchet end box end wrench to get them off. I used a open end and box end wrench but the ratchet end box end would have worked better if I had one at the time.
I've done it from under the cars that I have. One is a 24 Coupe and the other is a 21 Touring.
On the Coupe I finally had to twist of the nut with vise-grips. Ruined the bolt but got it off.
Its not easy but it can be done.
Just finished that laying on the back job! Working with wrenches overhead.
To remove the cotters, use a cotter pin tool, pointed tapered wedge like screwdriver tool, that inserts into the circle and you pull as you straighten the ends.
Without removing the cotters, the work is too difficult.
Henry bolted down that gas tank with he famous "3-point triangle" attachment. Cottered too, as you don't want 9 gal. of gas in a tank coming loose anytime
I've noticed several posts recently recommending wd-40 as a penetrating fluid, it's not very good for freeing rusty parts (but better than nothing). If someone is getting started in this hobby they will have better luck using a commercial penetrating fluid or the 50-50 acetone-atf recipe. Just posting what many have already discussed. jb
I did it on a '25 roadster with no problem.
You think a 20's car is bad, try an early 11 Touring tank. Dan
The guys have done a good job of answering your question, I might add only that if by chance you remove the bands from the tank pay close attention to the location 'cause once removed and snugged on the tank the three frame mounting bolts have to line up, been there myself and after a dozen or more trips under and over I add this comment!
This is what I had to do to get the tank out of my Chalmers-Detroit.