Just replaced the gas door hinge on my S60. The top and bottom pins are easy to get in. The middle two are less so. I ended up using two small bolts that screwed right in. Thought I would save everyone some headache by posting this idea.

 

I always snap the 4 pins out and take a straight pick and open the holes just a hair. Then slide the pins in from the back or turn them the opposite from how they came off and insert.

Then going on the car I use my small hammer for the upper and lower one. Then I use a universal nut driver handle(One you can swap sockets on) without the socket and tap that to push the center pins in.

 

Well that would work too. But mine showed a much higher grasp of the need to take a simple task and make it much more involved.

 

Ok we all have our own ways!! Not saying yours is wrong I just added how I do it.

 

I was lucky with my gas hinge, I went to open it, and it crumbled in my hands lol, I was like huh what just happened... lol , I guess my delearship just re-riveted them in, and only charged me for the oil change I requested.