If it homes to z max then send it to z 0 manually.
3d printer bed level gauge.
Start by tightening down all the screws so you have more room to work with.
A piece of ordinary office paper cut down to about 100 mm x 40 mm should work.
Home the z axis of your 3d printer.
Now level the print bed the same way you do with paper.
Connecting a multimeter in continuity mode causes a beep sound when the head is the correct distance.
Here is a good starting set of tools needed to maintain your bed level and nozzle gap.
Move your extruder to a corner and position the blade under the nozzle adjust the screw until the led will light up indicating that the tip of the nozzle is touching the feeler gauge blade repeat the process in the other corners until you find the perfect calibration.
For 3d printer bed leveling and nozzle gap adjustment you ll need a card of a size you can comfortably hold and slide between the nozzle tip and the build plate.
To actually level the bed is really simple it just takes some practice to get it right.