We have a Whirlpool, stainless steel, built in microwave and conventional oven combination wall unit that was installed more than 12 years ago when we built this house. There are two torsion springs that support the weight of the microwave door.
Several years ago, we replaced a failed, right hand spring. So, we already knew where to go for an excellent set of instructions and the replacement part itself. This is a common enough failure that the springs are widely available but, I decided to purchase from Appliance Parts Pro dot com because of the excellent tutorial with links to the correct parts and the promise of quick delivery.
The actual repair was almost anti-climatic. The first step was disassembling the door to determine which of the two springs had broken. Then the replacement spring was ordered and the door put back together for use during the two days it took the spring to arrive. Yep! Only three days total from the loud snap when the spring broke to a fully repaired microwave.
All you need is a screwdriver. The pliers I listed was a needle nose for picking up dropped screws. I used some small tie wraps in place of tape to restrain the spring centers as instructed in the tutorial. Heed the warning about the one fragile part of the door. I cracked ours, but was able to reinforce it easily with super glue and tape.
My wife is very pleased and so am I.