I got the smaller us version mudguards with 6 self tap screws and 6 spring clips for 2011 Prius. Is the metal where the mudguards fasten soft enough to screw into with hand pressure using the self tapping screws or do I need to predrill small holes?
I did not need to pre-drill, just used a hand screwdriver and a little pressure. Removing the tire before installing is a must. Also, I decided to add an extra screw towards the inner edge of the rear flaps as they just didn't seem to be held secure enough with just the two outer screws.
While on the note of removing the back tire, can floor jack be used on rear of car? noticed it can in the center front
Not sure if gen II is the same, but looking at the wheel well liners on our gen III, there are push-in style fasteners securing it at most locations, but near the bottom are different fastener style: having flat plastic face with a hole. Could be these are located to match mudflap self-tap screw locations? Off-topic: this second type of fastener look to be a royal pain to remove, if you ever want to take off the wheel well covers, to see what mud/grit might have accumulated behind. It might be possible to get them out, playing with a pin to get the tangs to release, but it is very tedious. I like to remove wheel well covers periodically, and there's invariably a lot of debris accumulated behind. Addendum: ignore the bit about gen II vs III, see now the OP has gen III.
I did some pre-drilling for some of the screws. The front is easy, since one can turn the wheels. On the rear, it probably would have been easier if I had jacked up the car and removed the rear wheels.
^ Ditto here. I used an small electric drill with very small bit to pre-drill all needed holes as the plastic was really tough. Didn't remove rear wheels, in hindsight would have made it far easier/neater but took more time and work. I was putting in fog lights same day.
removed rear wheels, marked holes, used small bit. It was a breeze putting mudguards on. It took about 30 min to do all four.
No need to remove the tires. You can use an angle bit adapter like this Draper 14 Piece 3 In 1 Angle Screwdriver Set - 43984 - Screwdriver Sets - Draper Tools - DIY Tools | www.DIYTools.co.uk You can find it at home depot or lowes. With this tool, you can cut the installation time down to 10 minutes for all 4
Here's a couple of pictures from my installation...If you look closely, in the second photo you can see the extra screw I added in the inside.
^ I used a piece of aluminum duct tape to hold down that part, but when it finally gives out I'll put in a screw, should have done that in beginning.
I see the extra screw you put on the rears...but maybe the 2012 flaps are different, the plastic section you put the screw on does not extend that far in the ones I just got in the mail...I wonder if they redesigned them somehow for 2012 models? Edit: I just noticed yours are US model, I got the Euros guess thats why they are different. Anyone with the Euro version put in extra screws?
You don't need to take the tire off if you use a small right angle ratcheting screwdriver. I like the extra screw idea, I used some high quality double sided tape and if that gives out I will take the extra screw approach