My iphone4 gradually developed a mushy lock button that i had to press with all my might to power on and off. I go fed up and took it all apart to see how i could remedy the issue. I figured it had to be a physical issue since the button worked if it was pushed just right.
You have to pull the back cover off and get the logic board out. Follow the Ifixit screen removal process. Then when you get to the point where the logic board is out, remove two screws holding on the power button mechanism to the frame. you should be able to carefully remove the assembly, then from the outside of the phone you can push the button through and remove it completely.
take a small screw driver and press the yellowish button and see if you can still hear it click. if you hear it, it can be saved. i read about people jamming paper in there or glueing various sized washers so i tried them and the paper solution only worked sometimes and i couldn't find the metal washer the correct size. i tried glueing bits of metal to the circular part on the underside of the button but didn't have any luck. you need to add a thickness that is JUST right. too thick and the button will remain pushed in and not bounce back. too thin and it wouldn't click the button.
What I did was take some two part epoxy (i used Locktite 3092) but any hard epoxy should work. I added a very small drop out of the mixing tube and used a sharp tweezer to spread it out a little thinner. Then after 30 mins of curing i laid some 400 grit sand paper on a flat surface and sanded the blob of epoxy flat. I installed the button and screwed in the ribbon with the lock switch and tried to press the button. it would not budge so I had to remove more material. i did this about 4-5 times removing just a little bit of epoxy till i got the click just right. It only takes about 10 mins of trial and error. Then i assembled it all back together and it works perfectly every time.
DO THIS AT YOUR OWN RISK
You have to pull the back cover off and get the logic board out. Follow the Ifixit screen removal process. Then when you get to the point where the logic board is out, remove two screws holding on the power button mechanism to the frame. you should be able to carefully remove the assembly, then from the outside of the phone you can push the button through and remove it completely.
take a small screw driver and press the yellowish button and see if you can still hear it click. if you hear it, it can be saved. i read about people jamming paper in there or glueing various sized washers so i tried them and the paper solution only worked sometimes and i couldn't find the metal washer the correct size. i tried glueing bits of metal to the circular part on the underside of the button but didn't have any luck. you need to add a thickness that is JUST right. too thick and the button will remain pushed in and not bounce back. too thin and it wouldn't click the button.
What I did was take some two part epoxy (i used Locktite 3092) but any hard epoxy should work. I added a very small drop out of the mixing tube and used a sharp tweezer to spread it out a little thinner. Then after 30 mins of curing i laid some 400 grit sand paper on a flat surface and sanded the blob of epoxy flat. I installed the button and screwed in the ribbon with the lock switch and tried to press the button. it would not budge so I had to remove more material. i did this about 4-5 times removing just a little bit of epoxy till i got the click just right. It only takes about 10 mins of trial and error. Then i assembled it all back together and it works perfectly every time.
DO THIS AT YOUR OWN RISK