tj
Guest
On the top side of the hooks should be a notch which is concave in shape and about 1_4" deep and about 3_4" long. This notch serves to align the top pipe and helps to hold the concave sections in place. Make sure the hold down pipe fits well in all of the notches. Some aftermarket concaves don't have these notches, some others don't have them inset properly. You may find some grinding necessary if this is the case. Other possibility is that hooks are too shallow on the right hand side, or are spread.