tbran
Guest
No the A series or 'black' heads were very reliable until they stared to get 'patched' or rigged unstead of correctly fixing. The first heads were made in '77 and called 78 models. later in around 80 they lowered the profile and made the snouts longer and replaced the cast blades behind the lower bearings with cast augers. These heads were produced in conventional and rotary design (offset throat). Through the years few changes were made to increase reliability which attests to general reliability. The heads do have a point at which they wear out. They do this like a cowboy finds a lost cow - all at once. They can be restored but the labor is the killer. In your case it seems the unit has an aliagnment or lose unit between row units which accentuates the problem. Units that were narrowed from factory setting, if not done properly were also prone to premature spline wear on coupling shafts.