I brought in an outdoor forklift on pneumatic tires. It is not the one
that I bought for $500, but another one.

This outdoor one, runs good, but has nonworking brakes. Quick
investigation shows that brake system is full of air, and that brake
fluid is leaking from the right brake drum (I can see it leaking).

This is a Cat V50B LPG powered forklift.

Am I correct in assuming that a repair is simple, though not
necessarily easy, and likely amounts to replacing or fixing the brake
cylinder os some such?

i