Learning how to repair a trombone trigger can seem daunting, and severe damage to an instrument's rotary valve requires repair by a professional. But most problems with triggers are a matter of routine trombone maintenance. By knowing how your trombone rotor operates and having a few tools and oils handy, you can troubleshoot the most common problems with trombone trigger. Keeping your instrument well maintained will avoid the need for major repairs in the future.
Inspect the tubes, slides and the trombone rotor for bent or dented spots and take your instrument in to an instrument repair shop to have severe damage fixed, since you will not be able to repair a trombone trigger at home if the rotor's motion is inhibited by dents in the metal.
Check the trombone rotor for loose parts or parts that may have fallen out, specifically the stop corks, screws, rods, strings and end caps. Make sure you know what parts your trombone rotor should have, since different rotor designs use different parts.
Tighten any loose screws, strings or end caps and replace any parts that have fallen off or broken, such as the string or plastic caps for trombone rotor ball bearings.
Restring the trombone rotor if necessary with a 9-inch piece of rotor string with a knot tied in one end. Thread the string through the rotary rod from the outside toward the valve, making sure the knot stops at the hole.
Guide the rotor string clockwise around top of the rotor stem and loop counterclockwise around the small screw on the rotor. Then guide the string around the bottom of the stop arm to the hole at the top of the rotor rod. Thread through the hole and loop clockwise under the rod's small screw. Pull the string taught and tighten all the screws.
Repair a trombone trigger that is excessively noisy when operated by putting a few drops of valve oil onto the joints of the parts on the outside of the rotor.
Repair a slow functioning trombone rotor by oiling the inside of the rotor. Remove the bell portion of the trombone from the slide portion and pull out the tuning slides on the pipes connected to the rotor. Drip several drops of valve oil down the tubes into the rotor and press the trigger several times, then remove the rotor cap and add a few drops of oil just inside the rotor.
Wipe off and lubricate the tuning slides with tuning slide oil before replacing them, and move the tuning slides and rotor every day for proper trombone maintenance to keep the valves from corroding and sticking.
Bathe the entire trombone if the instrument is in need of deep cleaning. Fill a bathtub with warm water and mild soap, and use a snake brush to clean out the insides of all the tubes.
Always use caution when conducting trombone maintenance and repair to avoid dropping and damaging any of the instrument parts. Store parts that you are not working on securely in the instrument case, and do not leave the instrument or its parts unattended in any location where they might fall or someone might step on them.