The ON-OFF-Switch and the Shutter-Release-Button are pretty similar on all Pentax-bodies*.
(KP is different though but I haven't inspected a KP yet and touch wood, I won't have to)
*K-S1 is different in size but same principle


For this manual I used a heavy used switch/button from a Pentax *ist-DS.


Disassembly should be clear, if not, check on the other tutorials I wrote!


Once you have access to that part, it looks like this:



1. Unscrew and take off that part with 3 pairs of "contact-bushes" (and don't bent them at all!) RED ARROW:



2. Unsrew and take of that round boomerang-shaped part GREEN ARROW:

Don't lose that tiny ball at the long end of this part, it is just fixed with some grease on the backside!


3. Now you can see a black coloured round metal spring, take that one off (red arrow):



4. Now you can take out the On-Off-Switch / Shutter-Release-Button:

Take off the "snap-ring"!

You can see, it this switch/button is pretty dirty ... and I won't clean it, I slaughtered this damaged *ist-DS for its solenoids and the focusing-screen only! (The use of the solenoids is well known by now in this forum, the f.screen is the better one for the K10D/K20D)


5. Now you have 2 parts:

a) The springloaded Shutter-Release-Button:

I only realized how dirty it was when I checked the photos!

and

b) The ON/OFF-Switch



All parts disassembled:



Clean well, apply some grease to this tiny ball and were it runs. I have used some thick bearing-grease which does not affect rubber).
Or "valve-lubricant" such as "Dow-Corning Molykote 111" or a good silicon-grease.



Assemble and hopefully all is well now!

[Dale H. Cook]

I would not use automotive bearing grease, as you don't know its chemical composition. It is designed for lubricating steel parts in a harsh environment and might attack other metals or other substances. I would suggest using white lithium grease whenever grease is called for in a camera repair.

[Paul the Sunman]

In the case of the on-off switch becoming very stiff, I have had good success (on the K5, K3, K1) switching it back and forth for several minutes while holding it under a stream of warm running water. Take the battery out first. I have not needed to disassemble any of them yet.

[photogem]

I would not use automotive bearing grease, as you don't know its chemical composition. It is designed for lubricating steel parts in a harsh environment and might attack other metals or other substances. I would suggest using white lithium grease whenever grease is called for in a camera repair.

I use white lithium grease on my bikes since years. But it is too thin for that part.
The bearing grease I use is for bearings covered with rubber and plastic sealings so I don't see any danger there.

@Paul the Sunman:
I have tried that method with warm water on my K5II but it didn't work that well. Has high shuttercount and suffered extrem temperatures.

Not all Pentax-bodies are WR anyway, so I wouldn't recomment the warm-water-method on those at all.

Disassembly is not that difficult really, but the result of a thorough clean is worthwhile.

[Dale H. Cook]

I use white lithium grease on my bikes since years. But it is too thin for that part.

In that case I would suggest Dow-Corning Molykote 111. It is a fairly thick silicone oil based grease which is pretty inert. It is one of the eight greases that I carry for work