I Hear You Knocking

I Hear You Knocking is a side quest in Fallout: New Vegas.

Walkthrough

 * 1) You access this quest at Fortification Hill after you talk to Caesar and speak with his subordinate, Lucius. From there talk to him until you reach the question about whether or not Lucius has employment opportunities. He will then explain that the Legion recently obtained a howitzer (which is aimed at Hoover Dam), but they do not have the part to fix it. He then tells you about a tribe of people called Boomers who are obsessed with such weapons.
 * 2) In the northeast corner of the Mojave Wasteland you will find Nellis Air Force Base, and after some careful running and dodging howitzer fire you will be stopped by a Boomer guard. If you then agree to go willingly with Raquel she will take you to the eldest of the tribe, Mother Pearl. While talking to her you can ask her for the firing mechanism but she won't be so willing to part with it. After questioning you will have free roam of the base.
 * 3) To get the part without theft, finish Volare! or become idolized to get her to let you have the part, removing its stolen tag when taken from the cabinet.
 * 4) Once you exit Pearl's barracks head for a row of curved corrugated buildings and enter the second building from the end. Once inside look for the gun cabinet in the corner, open it, and among other items you will find a howitzer firing mechanism. It's located in the Nellis workshop, between Loyal's house and the Nellis Boomer museum.
 * 5) When you return, search out the howitzer on the cliff. Examine the howitzer and replace the firing mechanism.
 * 6) Return to Caesar's tent, and inform Lucius that the howitzer has been repaired. You will gain Caesar's Legion fame as well as 100xp.

Behind the scenes
This quest is named after the song "I Hear You Knocking," probably the best known version being that of Fats Domino.