The back of the watch popped off and we can't get it back on. Help!

You will find an arrow head on the outside back of your watch where all the printing is. When you put this lid back on, this arrow needs to be aligned with a notch on the inside edge where the cover goes on. As you are looking at the watch from the back with the cover off this notch is in a northwesterly direction. If you doubt it then just hold the back on without popping it in all the way and hit your mode button to make sure that you hear the beeps again. If you do, then you've found the right spot...

Watch backs come off several ways, the most obvious would be screws you would see the screws be very careful not to strip them, the next way is screw off backs there would be even indentations all the way around back where the tool inserts to unscrew the back, if it is screw off you need to go to your local jeweler. The third way is just pop off, you need to make sure edges of watch around back lid are clean (you can do this with a tooth brush) and then look for a lifting spot a small indentation sometimes very hard to find! Use the blade of a pocket knife to gently pry it up it will make a popping sound when it comes off. good luck i hope this helps !!

Watch crystals are pressure fitted to their cases so that they are resistant to popping out. Think of a champagne cork, and how it expands when it comes out of its bottle.
Crystals are set into cases in one of several basic methods. First, a crystal may be installed from the back--watch cases are commonly assembled before the movement is installed. So, one potential way of reinstalling your crystal is to remove the watch movement from the case (if it isn't already) and try pushing the crystal from the back forwards. If this is indeed the way it was installed, the crystal should pop into position with a noticeable click or light thump to let you know that the other edge of the crystal has found the shallow groove in which it's supposed to sit.
Second, some crystals can be installed from the front using a tool called a "crystal lift." This tool has many little fingers that compress the edge of the watch crystal so that it can be slid into the case. Pressure is then gradually removed from the crystal, permitting it to expand into the shallow groove into which it's supposed to sit. Crystal lifts are easy to use in theory but somewhat finicky in real life; the crystal must be grabbed equally by all the lift prongs or else the crystal will have a tendency to squirt out of the tool before it's been completely set.
Looking at pictures of your wife's watch, it doesn't look to me like a crystal lift would do any good. I think instead that your crystal might have been installed using a third method. Looking at the pictures, it looks like the bezel--the metal top of the watch--separates from the watch body. If this is the case, gently pop off the bezel and push the crystal into it from behind. Then, push the bezel back onto the watch movement. It's possible that the crystal is kept in place by being squeezed between the bezel and the rest of the watch case.
If all of this sounds daunting, putting the crystal back in--assuming it's not cracked--is a minor job for a watch repair technician. It literally might only take 5-10 minutes to complete the job. If you're concerned about the appearance of the watch, it might be safest to pay someone the small amount of money to get this done right. Replacing a watch crystal with a new one usually runs about $15-25, around where I live. Replacing an undamaged crystal that's popped out should cost appreciably less, since a new crystal costs a jeweler between $5-25 for most standard sizes (diver's watches and strange specialty shapes will cost more).

Sounds like the seal was not fitted properly/at all?

Take it to an authorised Timex dealer for repair.

Most Bulova Watches have PRESSURE TIGHT backs. Meaning the back is applied with EQUAL amounts of pressure to the entire back. There are two(2) solutions:

1. Take the Bulova watch to an experienced watch dealer/repaiman, to have the back applied, or

2. CAREFULLY MAKE SURE THE BACK IS IN THE PROPER POSITION, then WRAP THE ENTIRE watch with a soft, cushy clothe and with a pair of pliers, CAREFULLY apply pressure to the center of the back plate, until the back covers seats to the proper depth(closed), at the same time BEING VERY CAREFUL not to crack the watch crystal!!

You need a watch case press/pliers to do the job right without damaging the watch. You can find them on ebay or, just take it to a watch shop and let them do it. Don't forget to replace the rubber gasket if there was one. If you reuse the existing one the watch will leak and be ruined if it gets wet.

There is a press for putting these back on.

RECOMENDATION:
Seek professional help.

GOTO
http://www.watch-clock-makers.org/
Hope this tip helps.

r/ David
http://antiqueclock.clockstop.com/

Sounds like you think that you bent it, Probaly you will need some one else to look at it and come up with a better idea. It may need to be rebent or maybe you have it in the wrong way. I suggest you get someone else to look at it

I found a "battery" website that had some suggestions that should be typical of any snap back case watch.
http://www.online-batteries.co.uk/whichb...

specifically they said that when you try to press the back on it must be flat (not one edge down as I had been trying) Put the watch face down on a non scratch surface and press with both thumbs evenly. If that doesn't work a press will be needed. If you have a vice a couple of blocks of wood to distribute the load on the front and back may work, otherwise take it to a jeweler with the proper equipment.

The thumb routine didn't work for me. I have a vice but figured many wouldn't so I tried something else first. I put the watch face down on a piece of wood. I found a small 2" long scrap of wood (3/4" x 1.5" approx) that spanned the back. I centered the back (aligned properly) placed the block of wood squarely and centered across the back and tapped the end of the block with a hammer. First try didn't work, second one did. I used a rubber mallet as the hammer but a regular hammer or other heavy object would work. The trick, I think, is to get everything lined up and square so the blow is centered and even.

Also, I'd suggest cleaning the back and the groove in the case and be sure the rubber gasket is properly positioned. This will give you the best chance of retaining the waterproofing. And remember to check that the watch is running before you do this. Some need to be reset (usually with a very small screwdriver or pin) after replacing the battery. There should be a small hole with some printing next to it. You may need a magnifying glass to see/read it.

Hope this may help you;

this video will show you were the spring goes next to battery