did you deduct the IRA's in each of the prior years. if yes basis is $0.   if you took as non-deductible TT should have tracked basis. 

Here's what the IRS has to say about it:

Although Form 8606 is normally submitted with a timely-filed Form 1040, the IRS will process a late-filed Form 8606—even one that is filed after the normal three-year statute of limitations for claiming a refund has expired. The Form 8606 can be submitted without a Form 1040 or a Form 1040X.

The Penalty for Late Filing 

The penalty for filing Form 8606 late is $50 for missing forms up through the 2017 tax year. The IRS sometimes waives this penalty if you can show reasonable cause for the delay. 

Note: Tax laws change periodically and the above information may not reflect the most recent changes. Please consult with a tax professional for the most up-to-date advice. The information contained in this article is not intended as tax advice and it is not a substitute for tax advice.