Need Help Mutoh VJ 628 damper replacement

I have 1624 and it looks like the same head as yours but with a little more room to work around it.
I'm not sure but I think you can change the dampers without removing the head height cross bar.
You want to make a note of what color is at each nipple so you get them back in the right order. I labeled mine 1-8 in a 2x4 grid matching the head position.
You can pull all the ink tubes off along with those plastic adapters on top of the dampers before the hold down plate has to come out. Just turn the little plastic base under the nut a quarter turn so they unsnap. Put the open ink tubes in something the ink won't eat thru - like one of the blue gloves - tape it to the top rail so it won't fall down and dump the ink. Then you can unsnap the damper lockdown by releasing the plastic hooks on both sides of the head. Here I am not sure as mine came straight up but you only need to go up a little then out away from the bar until it clears and then straight up off the head. You'll need some needle nose to pull the dampers straight up off the head manifold. Once you get them all off clean up any ink down in the bottom and make sure none of the old 'O' rings remained behind on the manifold nipples. Put a few drops of cleaning fluid on all the damper 'O" rings to make them easier to mount. New ones snug down onto the nipples - there is a note not to hold or squeeze them by the thin plastic membranes on the sides. Once all are in slide the lock-down plate on and wiggle everything around until the dampers are centered and you can snap down the retainer hooks on both sides of the head. Install the nut flanges onto the dampers - the have to snap into place on all 8. Lube the new 'O' rings, side the new nuts on the tube, then the 'O' ring. Match them up with your seating chart - tighten down the nuts as tight as you can with your fingers and then use a 9/32" (7mm I think) wrench to turn them another 1/4 turn tighter. You should see the 'o' ring start to bulge up just a little on the tube. Run a couple of strong cleans until the tubes fill with ink and you don't see any more air. Once everything looks good with no leaks and no air - put the covers back on and run some nozzle checks and test prints to see if everything is good.

 

Maintenance Manual states you need to remove the printhead before you can replace the valve dampers.