OT Zimmatic Sprinkler Question

[Howard H.]

How does the collector ring/elbow assembly come apart on an older (80's) Zimmatic sprinkler??

Does the elbow assembly just lift out of the center pivot frame and vertical pipe? Is there just a gasket in the vertical pipe that seals it and provides the rotation surface?

We've got a sprinkler that the collector ring brushes appear fine from the outside, but it keeps stopping in a certain portion of the circle and we think the ring may be lose on the inside...

Thanks for any advice,
Howard