Armando

I want to remove the cast iron arm assembly from the base, but am at a loss as to how it's attached. From underneath, one can see a round slotted brass nut (?) that presumably acts as a retainer for the shaft that the cast arm assembly is attached to (it is free and moves up and down). I've tried soaking in WD40 but there's no movement when attempting to unscrew. Any ideas?

I also would like to remove the retainer for the threaded hose attachment (which has one pin broken off) - it looks like this is held in place with an octagon fastener of some sort (I've never come across that type - it's not a stadard Allen key fitment). Again, advice appreciated.

There is a large brass hand-wheel that appears to be reverse-threaded and screws onto an insert that is located on the base. This may be some sort of water pressure adjuster (?) as it limits the vertical travel of the yellow spray arm assembly.... If I could remove the spray arm assembly, I could get the wheel off for polishing....

Hello, everyone! I joined this forum in my search for information regarding the 'Rain King' sprinkler.... I've been in touch with Paul (who has a few of them), but am still in need of advice.
 
As-purchased: 

I like to dismantle an object as far as possible, to enable more thorough cleaning/stripping/polishing/painting.
 
I removed the hose attachment (metal, not plastic), the two brass nozzles and retaining nuts, and (with some difficulty) the bottom screw (had to use a makeshift tool).

After presenting these to the wire wheels, cleaning and polishing, I now have the following: