You are going to need an impact driver to tighten the screws on the latch after you adjust it. You can't get them tight enough with a regular screw driver to keep them from moving. I adjusted the latches on my '66 Valiant and didn't use one. The doors worked fine for a while and then I hit a pot hole and it turned into a 3 door when the latch moved. Never did get that door open but the other 3 got the impact treatment and are fine to this day.