so im looking to do my back breaks for the first time on my 99 ford ranger v6 4.0 xlt 4x2, having trouble finding out if my rotors are 9 or 10in rotors anyone happen to know for sure

 

I hope you mean "drums" , 99's didn't come with disc brakes in the rear.

You should be able to just remove a wheel and read what is stamped on the drum, should say "MAX DIA" 9.xxx or 10.xxx

depending on what wheels ​​​​​​ your truck has you might be able to see it without removing wheel.

 

YES I MEANT drums and thank you