Hello, we are making a lego robot for a project. I found a SW part online for a gear rack and decided to use it instead of trying to measure and make it myself. This part is going to be 3d printed to match with lego gears for the project. We have tested it already and the dimentions are perfect, however its not long enough, so how do i make i longer? I tried mating many parts in a assembly, but when exporting to STL it just exports all the different parts in the assembly, so i guess i need to make the part itself longer. What is the best way to do this? (Also i think its a old part so i cant edit the sketch itself to make it longer)

Thanks in advance for the help! :D

Edu ​​​​​​​SOLIDWORKS ​​​​​​​