Maybe knowing how a leverage plot is constructed will help?
Consider a multiple linear regression model with Y as the dependent variable and X1, X2, and X3 as the independent variables. To create a leverage plot for one of the independent variables (for example, X1), do the following actions.
• Regress Y on X2 and X3. These residuals are the vertical axis of the leverage plot.
• Regress X1 on X2 and X3. These residuals are the horizontal axis of the leverage plot.
This comes from the ANOVA and Regression course offered by SAS.
Dan Obermiller