Don't break the glass. That won't help at all.
It's either gummed up badly or rusted shut.
I've never had this issue, but if I did, I'd think of...

1. Spraying some WD-40 onto the rusted parts as best I could. WD-40 is a decent cleaner and might break it free without using more caustic/damaging approaches.
2. Heating it with a torch (perhaps BEFORE the WD-40...don't ignite anything)
3. Penetrating Oil. Again, tough to get on the parts that need it.
4. Smack the ends of the lockdown bar just a bit with a rubber or rawhide mallet. Left then Right. Repeat.

That's all I can offer off the top of my head. Unless you want to dump another Coke down there...
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

I have had a couple I thought would never come out over the years but after a little time I managed to get each of them out without doing any damage. One thing I have had to do a couple times is to pry handle over a little to get release bar over enough for lock down bar to unlatch.

About a month ago I had a machine that lock down bar came off easy but machine had so much stuff spilled on it over the years glass just would not slide out. I actually had to dump warm water on both sides to get soda or beer to soften up enough to let me slide glass out.

You will get it - just take your time and keep messing with it.

One other tip is try putting something under one front leg - then the other. Sometimes if cabinet is twisted a little glass will not release. I use a piece of scrap wood about a 1/2 inch thick.

To bump an old topic, I just rescued a Jacks Open (my first pin!) with this very problem. I am currently unable to get inside any further than the coin door and back box. I have slid a putty knife between the length of the bar & glass and am going to locate a mallet to give it a few love taps. I've only seen photos of a disengaged lever so at least I know which way it's supposed to unlatch. This is all new to me so my goal is to release it with minimal destruction.

I notice that the OP did not report whether or not he had any success?

Ya...that's frustrating when the solution isn't posted. Well, you can right that oversight with your success!
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info

I have encountered this a couple of times.

I just take a hammer to the latch/release handle inside the coin door. I start light and increase the strength of the hits until it releases. Then a judicious amount of Tri Flow Teflon lube to keep it smooth.

Mike O.
Team-EM

This would explain it > http://pinside.com/pinball/forum/profile/ptbopinball One and done?

Thanks for the tip, I will give this a try!

Make sure that the secure bolt is not still in the handle, it looks like a pointed bullet. Its probably not there anymore but take a close look for it.

John P. Dayhuff
Battle Creek, Mi.
269-979-3836

i had the same problem, coincidentally a jacks open as well...

after much pounding, pulling and cussing, i tied a weight (i used a battery from a weed wacker, but anything heavy will do) to the latch and just let it hang... lo and behold, gravity eventually did its job and pulled it free...

note: clean WELL after getting it open... remove the latching mechanism part from the machine and get all the crud out of it as well...

Success!

With a combination of very mild hammer taps to the release mechanism, light taps to each side of the lockdown bar, a putty knife between the length of bar and glass, and finally a large flathead screwdriver as a lever (I should have tried that first, in retrospect), my lockdown bar is now free and all parts will be cleaned.

Thanks again to all who replied!

I've owned half a dozen EM Gottlieb's and never had a stuck lockdown bar... until I started working on my latest acquisition, tonight. Yes, this too is a Jacks Open! Hahah! Wild coincidence. Anyway, after checking here first to make sure I was not being a knucklehead I used a rubber mallet to move the lockdown bar back and forth, left and right. Importantly, I also used an adjustable wrench to give me a better grip and more leverage on the latch, applying downward pressure the entire time I was using the rubber mallet. I could feel the latch move the slightest bit with each tap, and it finally came loose.

I needed to use some lube to get the latch to move freely, even without the lock bar in place, and now all is well.

Best,
Mike

Get vice grips to grab the tab and just use force. I had this issue with jungle Queen and it eventually worked loose.