A floating bridge is a term that refers to a guitar bridge that is raised up and not flush against the body of the guitar. Some guitar players prefer a floating bridge, as it allows them to manipulate the whammy bar in both directions instead of only forward. However, a Fender Stratcaster bridge that floats too much can damage the bridge, as well as put too much tension on the neck, causing it to bow or bind in a way in which it is not meant to.
De-tune your guitar strings. You must release the tension of the strings before adjusting the bridge. If you lower the bridge position without releasing the tension of the string, the strings will undoubtedly snap and your guitar's neck could also be damaged. To detune your guitar simply turn the tuning knobs, or machine heads, clockwise, slowly for one to two rotations.
Unscrew the six screws that holds the plastic cover in place on the back of the guitar. This plastic piece covers the guitar's springs, which put tension on the bridge.
Locate the two large screws inside the back of the guitar, which fastens the entire "Tremelo" system to the guitar's body. Turn the screws clockwise to tighten them closer to the body of the guitar. This will force the metal claw that the springs are attached to, to pull closer to the body of the guitar, which pulls the bridge back down into place.
Re-tune the guitar to see if the extra tension of the strings being in tune will pull the bridge back up and make it still "float." If the bridge once again comes up from where it should be, detune your guitar and repeat step 3. Continue this until the bridge remains in place while the guitar is in tune. If you have turned the two large screws move than three or four complete rotations and the bridge still remains floating, you can purchase one or two extra springs and attach them next to the current springs in the guitar for added support on the bridge.
Adjust the "Truss Rod" of the guitar to alleviate any extra tension on the guitar's neck. The truss rod is the metal rod that runs along the length of the guitar's neck to hold it straight. Place a capo on the first fret of the guitar. Hold the last fret of the guitar on the 6th string. Use your feeler gauge and measure the distance between the bottom of the string and the fretboard on the 8th fret of the guitar. The correct measurement should be betwen 0.008 and 0.012 inches. If the string is too close to the fretboard, stick the long end of an Allen wrench in the hole at the base of the guitar's headstock and turn the wrench counterclockwise. If the strings are too far away, turn the wrench clockwise.
A floating bridge is commonly caused by adding higher gauge strings to a guitar. This adds more tension to the neck and subsequently pulls the bridge up out of place. Note that the bridge does not have to be completely flush with the guitar's body, if up to 1/8 inch of the bridge floats, that is not a problem.