Thank you everyone for the tips so far! I got overloaded with work yesterday but today I had more time to work on this.
I did check the drain line at the bottom of the assembly under the labyrinth seals and it was not blocked at all. When I removed the line and stuck my finger in the resultant hole, there was no debris or restrictions I could feel. So I don't think it's as simple as a blocked drain line (although I was hoping it was). I managed to get the chuck off (and ruptured my colon catching it when it started to go - THANKS for the tip to put a bar in the spindle to prevent it falling - that sucker must weigh over 200lbs!).
I also removed most of the parts surrounding the hydraulic actuator. When I look into where the chuck was, it appears the inner tube is now free to slide around and that means it should be able to come out from the back along with the cylinder (if it needs to come out that is - see below).
However, do I need to remove the hydraulic actuator AND the drawtube together? Or should I be unbolting the actuator and just removing that? Please see the pics I posted below...
There is a metal ring held on with clips at the back of the cylinder. This is connected to a pair of microswitches that will just be to detect whether the chuck is open or closed, so I will get a clip wrench bit enough and get that off.
On the cylinder itself, there is the actuator itself that looks like a motor, this spins freely with the mount, hydraulic lines and drain line removed. Then right in front of it is a large metal cylinder slightly larger in diameter than the actuator - this has a big set of bolts on the front and some hex socket bolts recessed in the rear. Then there is a brake rotor (may be one big piece that's also the front of the cylinder - I can't tell) then another set of large hex head bolts right before the tube disappears into the casting of the machine and re-appears about 3' to the right inside the machine where the chuck is.
It appears I can either remove the brake calipers and try to slide the whole thing out, actuator, cylinder, and drawtube all in one. OR, I can unbolt it somewhere along the way and just remove that part.
I'm guessing I want to do the latter? But before I start can someone confirm that? I am guessing that in the cylinder part on the front of the actuator will be some connection mechanism to the drawtube, and that's where the seals and o-rings will be. But if I have to unbolt it at the right-most (closest to chuck) set of bolts I will have to remove the brake system from the spindle to get the rearward part off the machine.
Any tips so far? I'm planning to get it off tomorrow or on the weekend and hopefully have the beast up and running again next week. Hopefully being the operative word here
