Here's how to tweak your steel guitar and adjust the pedals and knee levers for proper and comfortable operation. There is also information on how to change the action (shorter, longer, easier, etc.) of the pedals and knee levers. Trouble shooting guides are provided to assist you in diagnosing causes of your steel guitar's inability to "stay in tune".
Make sure your cross-shafts have a small amount of slack (about 1/32 inches).
The slack can be observed as a small gap which appears between the front rail and the cross-shaft when moving it (as shown above). Some Guitars may use thrust springs to hold the shaft against the front apron or rail. They should still demonstrate slight movement.
Carter Steel Guitars Website https://www.steelguitar.com/adjustments.html