mine are pretty far gone how would I go about getting started to replace them? One side at a time? Fester.
I did my roadster one at a time but if I had to do it again I would start with a bear frame and mount the new subrails and reasemble in sections repairing problems as you assemble.
If you put in on 32 rails, steadfast makes a nice rear subrail kit. Im sure many others make a model a kit. Get out wizz wheel, grinder, fire wrench, & cut the dead parts out. Take some pictures if you want to work back to original. Helps to have another friend, or your other car to occasionally go back to view. I'd let body float over rails with jack, lift, or crib 2x4's to your desired stance, then tack in new subrails. I say tack in...because I learned the hard way, after you get tires, engine, two people, 16gallons of gas & cooler, you may start moving things around in mockup before final welds.
Measure twice. Cut.cut. cut. Cut. Measure. Cut. Buy more cutoff wheels. Drink beer take picture. Measure. Cut.cut.cut. weld. Buy 2 more 4"grinders.
I made a table top with two pieces of MDF and placed my '30 Roadster subrails on it. I'm using originals from three different bodies. The cowl had rails that were cut at the back of the doors. Another set went from a cowl to the wheel well, and I've got a thirs section that went from the well to the back. Goal is to have a dead stock body, with everything fit properly, then buy the Steadfast kickup for mounting the body on a '32 frame. Bob
Build the subrails first and separate. I like to use rivets just like the originals on the cars I do. Take lots of measurements from your original and build it from the cowl back. I love model A's because almost every piece is riveted and easily removable. Repair every piece separate then install on the new subrails. Posted using the Full Custom H.A.M.B. App!
I did it this way too assembled the entire subframe on the frame itself then placed the body on the sub frame. The bottom 6 inches of the enitre body was gone except for the firewall, started there and worked back using the measurements other model A coupe guys had given me here and on the Ford Barn.. BUT! I welded everything together since this car was never going to be confused with a riveted stocker.
You can buy the complete subframe assembly, put it on a table and start working on the body. Cost is likely to be the same if you build it yourself but the time and trouble saved will be enormous.
Brookville roadster has complete assembled subframes but they are expensive and hard to ship.. I like Walter's suggestion in post #2...
I think that will be what I need to do. I think I will try to find another one so I can steal a few pieces from it.
On the roadster I had a drew a set if grid lines in a 4x8 sheet of ply wood and then centered my body on it. I only replaced the rear halves on mine. I also cut them at 90 degrees to the rails so they matched up well. It actually was really easy