Rossi Squire HELP

Hi All
I have Rossi Squire coach gun that is very hard to open. I've given it a good clean and there is very little improvement.
When you break the gun the hammers cock with the sears engaged before the gun is fully open. To open it far enough to insert new cartridges requires more force and you see the hammers being pushed back past the point they need to be cocked. Very slow for CAS.
My understanding is the hammer spring rods need adjusting ( shortening) and possibly the springs lightened?
The main problem is getting the hammer spring rods out. I've removed the sears and hammer pin, but the rods and hammers don't come out.
Do I need to also remove the main hinge pin to get the rods out? If so is there any any tricks to getting the hinge pin out. The pin has slotted covers over them, which I assume are threaded in. I've removed the little locking screws but the pin covers don't want to come out. The screw holding the bottom cover on took a lot of force and heat to get out. I think the previous owner might have got busy with locktite.
Is it a case of more effort and more heat.
The action is different to a lot of shot guns I have had apart. See photos below.
Thanks in advance.
Attachment 171001
Attachment 171004