Hi Kyle, Good suggestion from Tony above.
Now if that doesn't work, look at the inner face of the back-plate and remove the split pin ( tricky, it may be rusted in ) and then the vertical clevis pin that holds the handbrake lever to the handbrake cable end. Then gently knock the handbrake lever back towards the back-plate. If the handbrake has seized in the "on " position this may be where the problem is.
Now for stage 2... If the above doesn't work then a common 1850 problem has occurred.
The rear shoes on the 1850 are quite narrow and if they do seize in the "ON" position then the brake shoes wear down and the rivets in the shoes cut 2 tram-lines on the inside of the drums and the self-adjusters then lock them in place so removing the brake drum is very difficult.
When I had this on MPD many years ago I had to use a large 3-legged puller to get the n/s drum off.
Budget for a new brake drum, new linings and a steady-spring kit.
Good luck with it,
Tony.