420D deere no steering

steering wheel will not move left or right. removed HMU found nothing inside except the check valve was very hard to remove, cleaned and reassembled and the problem is the same. the HMU spins freely until the air is purged from it, when it sees pressure it locks up. This model has the priority valve integral to the loader control valve. Pressure at priority valve is 2100 lbs. The initial priority valve flow test on the LS line to the HMU was within limits. pulled relief from priority valve...

420D deere no steering

420D deere no steering