T21315T John Deere 350 steel steering clutch disc. These steering clutch discs fit the John Deere 350, 350B, 350C, 350D & 400G tractors. The John Deere 350 series tractors require 7 of these T21315 steel discs per side. The John Deere 350C and later tractors utilize a wet steering clutch and require a mating bronze disc, part #AT117553. The AT117553 bronze disc can also be substituted for the T20790 in the 350 & 350B for severe service.