Suntour Accushift Derailleur Overhaul

I bought a well used Suntour Alpha 4050 rear derailleur that could use some help. I have this same model on a 1988 Schwinn Letour, and it shifts very nicely.

Time to take it apart. I'll start with the mounting pivot. It's spring loaded, which is unusual for Suntour. There's a small C-clip that can be pried out with a screwdriver:

 

That clip will go flying. After retrieving it from across the room, you can slide out the mounting bolt and spring:

 

To service the pulley knuckle, remove this philips screw:

 

Now let the pulley cage unwind, and find the right position to slide it out. You need to rotate it just right so that it will slide out of the knuckle:

 

There are 3 positions for the spring beneath the plastic cover, I'll just use the middle one for reassembly.

 

The pulley screws are 9 millimeters. A socket works best for the screw on the back of the cage, since it is recessed into the plastic cage plate:

 

Pulleys disassembled:

 

Exploded view:

 

Now I can clean everything.  For reassembly, I added grease to the knuckles and slid the springs into their mounting holes:

 

Next I reinstalled the mounting bracket by rotating it against the spring and pressing it into the knuckle. Then I secured it with the C-clip (I pressed it in with a flat screwdriver, but it's easier to use pliers).

Now I reinserted the pulley cage plate into the pulley knuckle.  First I had to insert the spring into the middle mounting hole, then wiggle it a little bit while pressing it into the knuckle. The toughest part was installing the cage stop screw while holding the knuckle back against spring tension.

 

Next I reassembled the pulleys:

 

 And screwed the cage back together:

 All done. I considered sanding out the scratches and touching up the paint, but I actually like the worn look.