Bought a 4x5 Graflok for a friend, mounted it on my Crown to check focus.

Not sure of proper names for the parts. The 'chrome' latches that one presses to release the screen ass'y from the back on mine, snap firmly and audibly against the triangular cast 'stops' on the panel ass'y.

The 'new' back seems like the latch sits about 1/16" away from the stop, so the GG screen ass'y does not sit flat against the back.

I can't feel a difference in the upper or lower springs, but my fingers are not calibrated. I can't see under the latch where the spring contacts it to see if there is something under it.

Can one torsion spring get loose? They look the same, and one is not broken.

Thanks

Well.....the manual shows 2 graflok back assemblies: 34796G1 for Speed Graphic and 34796G2 for Crown Graphic. No explanation of the differences, both use the same parts.
Will the Focus panel (frame assembly-focusing) from your Crown fit properly on the new to you Graflok back?
Does the focus panel for the new to you graflok back fit on your crown graflok properly?
There are 4 parts on the focus Panel involved: Arm assembly upper, spring upper, arm assembly lower, spring lower.
Compare the pins that the arms latch on on both backs and verify that they are in the same position, use a precision ruler to measure their positions.
Compare the two focus panels for correct assembly of the arms and springs, the new to you back may have a spring misinstalled, wrong spring installed, the spring could just be weak, or the arm may be bent.
Apply a drop or two of light machine oil on the shaft of the arm and end points of the spring and exercise several times. Check for burr(s) in the arm movement path.
If I think of any other possibilites I'll post them.

Thanks. I'll check all that out when I can. having a med procedure done today and I may not be able to do stairs for a while.

A couple things I've found with Grafloc panels.
They get stiff and gunked up (corroded) just like anything else. The axle rod of the chrome arm, the part that runs through the spring and the hinge point in the body of the panel, get stiff and with time wont allow the spring pressure to move the arm easily against its stop (this is partof the chrome arm where it stops against the panel), and thereby the hook-lock on the camera back. If you lock a panel into position and it is loose and jiggly on the back this is probably what is happening.
Simply apply a drop of light lube oil to all the points where you see the rod passes through and perhaps a little to the spring itself, which I do on obviously corrroded panels. Allow to sit for a bit and then work the arm and maybe add a little more lube (any penetrating lube should work fine to get started but I like to use Triflo on these). Should notice a rather dramatic difference almost imediately.
Another problem is that the arms do get bent and missalligned from misshandling, or misshaps etc...
But first lube the arm hinges as suggested above. Then check that the arm is hooking under the locks on the back before the arm stops touch and holding the back snuggly without any loosness or wiggly jiggly. Should be pretty positive. If the stops stop the arm too soon they need to be adjusted (slightly bent or tweeked). If the arms are not sliding in to the hooks easily they could be slightly bent. Make sure the Grafloc slide bar locks are all the way out, and see that the panel arm locks allign without any extra help. I have had to re-set a few arms and was delighted with the results. I use a pair of long flat tipped duck bill pliers sort of like needle noses. A strong pair of needle nose can work also. Be careful not to overbend and stress crack the arms. Should only require slight adjustment if any.
When I lube grafloc arms this is one place I am not worried about using too much lube, and lay it in there. There is galvanic corrosion caused in the hinge points because of dissimilar metals and you'll notice that the panels can corrode on thier own anyway, so simply get it working and wipe away the excess. The springs, being steel, rust also so a little oil will be good for them. When I lube the points I manipulate the arms ptretty far, much farther than a film holder would turn them. Ilike to get the lube in there and break loose the junk. So I pull them back about an inch or more, probably a couple, a bunch of times. I do however ussually remove the glass and fresnel panels to clean them anyway and when all is cleaned and re-assembled it's a good thing.
Have fun and I hope all well and you can get up stairs soon...

Re: the different part numbers for backs to fit speed graphics and crown graphics, the speed graphic part has electrical contacts to fire a flash as the roller curtain shutter opens, either back will work on a Crown. FP bulbs only.

One latch was indeed bent. I couldn't see it until I tried and found useless shimming under the spring end, then took the glass panel ass'y off. A pair on needle-nose pliers under the short lever and gentle torque a few times until the gap was gone and it's good.

Thanks Bert, and others for suggestions.