What you are describing, one LLC member performing more actual work than the other but still maintaining 50/50 equity is called Guaranteed Payments or Payments for Work Performed. Your partnership agreement can and should delineate this. It can be an actual specified amount or can be flexible and based on billable hours, or the work you do.
These guaranteed payments are not subject to payroll taxes but you are subject to self employment taxes, social security and Medicare, as well as this is ordinary income to you, and a deductible business expense to the company.
The company reports it on line 10 of the partnership return, form 1065 as well as on your K-1
