Altimeters are essential instruments for flying planes. A sticking altimeter can be dangerous for the pilot and passengers. Sticking altimeters are generally caused by a malfunctioning vibrator -- the mechanism which prevents the friction in the gears from affecting altitude readings -- or dirt and debris in the altimeter system preventing the internal mechanisms from producing an accurate reading. Repairing a sticky altimeter involves locating the internal vibrator, if your altimeter has one, and cleaning the debris from the inside of the instrument.
Remove the altimeter from its housing unit, if it has one. Altimeters built in to planes are often secured in a housing unit. To remove them, use a standard screwdriver to gently pry the altimeter out. Once the altimeter is out, disconnect it from any cables holding it to the altimeter housing. These cables are removed by pulling apart the plugs connecting them to the wiring.
Remove the back casing from the altimeter. The process for removing the back casing varies based on altimeter models. Some can simply slide or be pried off, while others are connected to the face of the altimeter with screws, which need to be removed.
Locate the internal vibrator, if the system has one. The vibrator will be a spring system inside the altimeter and attached to a power cable that connects to an external power source. You will have disconnected this cable when you removed the altimeter from its housing. Clean the vibrator mechanism with compressed air and a rag.
Spray compressed air into the internal portion of the altimeter to remove any excess dirt and debris which may be sticking the system and preventing you from getting an accurate reading.
Spray a small amount of CorrosionX or other lubricant into the altimeter system. This lubricant will encourage the streamlined movements of all portions of the altimeter and allow the reading needle to move more freely.
Replace the back casing of the altimeter, screwing it into place if necessary. Make sure all externals cables are fed through their appropriate slots in the back casing. Connect these cables to their power sources. Reinstall the altimeter into its housing if necessary.
Use your altimeter at low altitudes to test it. If the altimeter is still sticking, it may require professional mechanical repair or you may need to invest in a new altimeter.