[s800]

Anyone have a pdf or anything else for the Pentax 67 55mm f/4 SMC lens?

Need some assistance with disconnecting the rear (inside) aperture mechanism from the ID of the focusing helix.

Thanks much!

[MysteryOnion]

I don't have a exploded view, but if you are pulling the lens open due to oil on the diaphragm? The challenge is that you will need to open the lens from possibly both sides. On the Pentax 6x7 lenses I've open and cleaned a few of them and they seem to have similar layouts. Here is a basic walk through just to give you an idea.

To access the Front as far as seeing the Helicoid... (oh... -to- meaning going from one to the next)
Name Face Plate -to- Shroud and screws -to- Clamping screws -to- Focus sleeve (if the Name Face plate has no spanner notches, try wearing rubber gloves for extra grip.)

To remove front groups to expose aperture cavity...
Retainer ring with lens spanner -to- group sleeve or next retainer

Working from the mount side...
Mount screws -to- Mount plate -to- flat black Shroud plate screws -to- Shroud plate -to- Aperture Position Blade -to- Aperture Yoke -to- Yoke spring -to- Stop-Down Lever spring post -to- Stop-Down Lever pivot Screw and spring

Removing the rear group...
Shroud/Sleeve with lens spanner or Retainer with lens spanner. NOTE: that most are a rear group that is easily spun off.

Removing the aperture cup...
Assuming that there is no obstruction from the front, you will see the cup or aperture assembly can come straight out...also you may need to separate the upper half from the base or cup to completely remove. From the rear, remove three screws, but not that they are not fully seated, only thread locked in place. The tension is low when reseated and the screw must be thread locked back. Do not try to remove more than the screws holding the cup.

Thats it... or all in general...been a while since I was inside the 55mm so I hope it helps.