i overhauled a simplex rd recently and am having trouble understanding how to mount it in the on-frame derailleur hanger. i'd like to use the top portion of this diagram as an example of the issue:



the derailleur is not exactly like that pictured, but does have these similar parts:

- hanger bolt (3876). mine has a tiny hole for the spring. the bolt is hollow and threaded inside to fit the screw described below.
- spring (3885). mine installs in the front of the body, before the bolt, and is secured to both bolt and derailleur body.
- bracket (3563L). mine is teardrop shaped, has no tiny hole for the spring, has a square hole for the bolt, and has two notch-like-things (not merely one as shown), one bigger than the other, and they project on either side of the bracket (so one hugs the derailleur and one fits against the frame).
- screw (2551A). the bolt (3876) does not screw into the frame, so this screw is used to fit inside the hollow bolt to secure the derailleur.

questions:
- how do i load (tension) the spring? or do you pre-load the spring at all?
- which side of my bracket faces the frame?
- if you think you might have a similar derailleur to the one i described, could you post a pic or provide some info?
- is it wholly necessary for the spring to be engaged for the derailleur to work adequately?

many thanks.