Do your old guards have bars on them pushing the sickle bar forward? If it does you’ll have to loosen them up and slide them back.
This is my guards/bar setup.........the mower bar itself is about 1/2" or so thick x about 4 inches fore and aft.........and 9 feet long......so offset that much, it puts a lot of strain on the hitch end. Bolted to underside of the bar are the guards.........bolted flush to the bottom, and at front end is a small turned up lip / claw that prevents guards from moving side to side. These are held up by a special plow bolt style like a carriage bolt......no movement at all......fore and aft or side to side.
The problem I seem to be having is with that small lip / claw. The original old guards have a lip of maybe 1/8". Guards ordered from JD using same part number have a different, taller lip. Now maybe 3/16" or more..........and that seems to be where the problem lies.
![[Linked Image]](https://trapperman.com/forum/attachments/usergals/2026/05/full-51773-294111-img_2330.jpg)
The sickle bar......the bar stock to which the sections are riveted to.....slide along just above that lip....at least with old guard. Very close tolerance, but not touching. With new replacement guards, it slides on that lip........so does not drop down into the slot to allow sections to register on and touch the ledgers on the guards. These have to touch so they shear like scissors.......and these were not.
Green guard on right is my 5th and final option for my Obi-Wan replacement guard. My last and only hope.
![[Linked Image]](https://trapperman.com/forum/attachments/usergals/2026/05/full-51773-294114-img_2328.jpg)
If that works, then on to replacing all the hold downs, pull and sharpen sickle, etc. Plus there are 3 or 4 major adjustments to get this set right to cut. There is a lot to know to get these tuned and running right. There is a reason why the modern era replacement is a disc bower...........but takes a big tractor and big HP to run one of those.
Come to think of it, if OP has a big enough tractor, a disc mower might work for him.