It would probably be easier to do in place. If surface rust it can be sanded or ground down relatively easy. If rust through then patch or replacement is needed.
To patch or replace you will need to remove the windshield.
The bottom half of the hinges are supposed to have nuts on them. You will need to;
1. remove the hard or soft top
2. remove the link bard from the roll cage to the windshield.
3. loosen the dash panel or remove it altogether.
Mines not near as bad as yours is - or so it appears. But how would one go about fixing this issue? I don't want it to get worse. I would assume just sand it off and re-paint. Any good articles on rust fixes?
1992 YJ, 2.5L, 33" Tires, 2.5" Body Lift, Stock Springs, AX-15 Trans, Stock Transfercase, Stock Axles.
If it doesn't leak or anything you could always just sand it down and use a type of cosmetic body filler to fill it or even use some reinforced fiberglass filler and sand it down smooth. That would prevent water from getting to the rust and may help or slow down more from forming. Just a thought
If you think the rust is only on the outside surfaces, think again. I guarantee you, you will find rot holes in the glass channel. The amount of visible rust on my windshield frame was about the same as Huntsman180, but when I pulled the glass and gasket out, there was a lot of rust and some holes in the channel. You probably don't want to hear this, but to do the job right, the glass and gasket needs to come out.
Here are the steps I took to eradicate the rust on my windshield frame.
1. Pull glass and gasket
2. Scrap every bit of the adhesive out of the channel
3. Send the frame out for a thorough sandblasting
4. Completely coat it with Ospho
5. Spray the insides of the frame with Eastwood's Internal Frame Coating
6. Spray the outside with two coats of two part epoxy primer
7. Fill holes with All Metal filler
8. High build prime and paint
Copperhead is right about the rust. I am retired from the autobody trade and found that where there is smoke there will be fire. On my '87 YJ there was no visible rust with the outer windshield molding in place. I pulled the windshield in order to re-paint the entire vehicle another color. What I found was some glass technician during a prior windshield replacement had cut through the paint and that is where the water laid and rusted the channel through. After considering the replacement cost vs. the repair effort, I bought an aftermarket windshield frame for $130.00 and it worked out just fine with a little additional attention to some minor details. In hindsight, I should have simply replaced the frame, glass and moldings and left the old windshield in the old frame. Someone poorer than me would be glad to have a good windshield & rusty frame for free.
Simply filling rust holes with all-metal or Bondo will fail!! It will look good for a year or so but the rust will come back. Why waste your time when a new windshield frame is so cheap and easy?
Rather than use a knife to cut the windshield out from the inside, I pulled the outer molding off and used a length of piano wire to cut the windshield out from the outside. It's more work but I was able to save the windshield glass. Most glass technicians use a special windshield urethane adhesive to install windshields (about $20.00 a tube) or a butyl tape kit may still be available.
Unfortunately they are right, my frame showed no rust, but the prevous owner had put silicone on the cowl gasket and around the windshield. Great idea it theory, but all the silicone did is hold water in and rot everything out. Pin holes in the frame needed to be welded up, and the dash and cowl was a mess as you can see. The best way is to pull the whole thing.