Disassemble 135mm non-ai

[mozart1973]

Hi!

I have an old nikkor-q 135mm lens which I want to use on my D90. I need to get the apeture ring off. I unscrewed the five screws to get the mounting ring off first. But the is some spring or something that prevent it to just be pulled out.
Does someone here have a guide how to disassemble this good old lens?

regards
Atha