We lived overseas for three years in the late 1980s. I was teaching part-time in a local school. We reported the income (income earned abroad) to the IRS in order for me to be able to add funds to my IRA account. However, we did not pay Social Security or Medicare taxes on this income. I have 34 years of income reported to SSA, so in that regard I am OK. However, adding these three years of income, even if we must pay additional SS and Medicare taxes, would likely increase my SS payment when I retire--adding the 35th year and deleting one or two of my lower earning years. Is it possible to do this, and, if so, how would I proceed?
The answer is no, and for more than one reason. First and foremost, voluntarily paying Social Security taxes on earnings or any other type of income that is exempt by law from Social Security taxation is not permissible. If the earnings that you had at the overseas school were subject to US Social Security taxes, your employer would have been required to withhold and pay the appropriate Social Security taxes.
Secondly, even if your earnings would have been considered subject to Social Security taxes, such as self-employment earnings for work as an independent contractor, the appropriate Social Security taxes must be paid to the IRS within 3 years, 3 months and 15 days from the end of the year in which you had the earnings in order for the earnings to be credited to your Social Security record.