Retirement tax questions

I want to max out my 401 contributions to offset a high tax debt if I apply for my SS now while I am still working.  I can't afford to catch-up without it. My SS is smaller than my survivors benefits at 67 I would be retired then and would change to his SS.

I just want to be sure my maxed out 401 contributions would LOWER my tax debt so all my Social Security wouldn't be taxed away.