I performed the TSB as listed for 2020 vehicles just a few days ago on my 2021 model year. The 2021 bottom of the seat does not look exactly like the 2020 model years according to the TSB pictures. Apparently and I can only assume this, Ford tried to fix this issue by molding the sub-seat differently by adding more support ribs, closer together.
That said, that Mickey Mouse TSB (I laughed out loud at the fix when reading the bulletin) though modified to work on a 21' took the side-to-side motion and the noise out of my seat.
The seat's architecture would not allow the 1" heater section of hose described in the bulletin to fit in the voids of the sub-seat on the 2021 model year. In fact the section of heater hose I ended up using was only slightly wider than the 3/8" band clamps required to hold the hose in place. The seat's rib voids are only that wide. I didn't even pull the module.
I used 2 pieces of hose and two clamps positioned differently than the TSB would have had me do it due to the seat's updates. The noise I was hearing and the movement I was experiencing was gone immediately. The repair is straightforward and takes about 20 minutes to perform. You'll need a couple of inches of 3/4" heater hose and two screw-type band clamps. Two on each side may actually be better. There is room for these above the seat module.
Now having said all that I still think these seats are noisy when I initially sit on them I hear a noise while I'm putting my weight on the seat. Adding the two additional clamps I mentioned above may or may not help here. Once my weight is on them I don't hear anything and there is no more seat shifting on corners. I'm sure I could silence this noise too but it might actually require the seat to be pulled and shimmed. Perhaps another day.
That said, that Mickey Mouse TSB (I laughed out loud at the fix when reading the bulletin) though modified to work on a 21' took the side-to-side motion and the noise out of my seat.
The seat's architecture would not allow the 1" heater section of hose described in the bulletin to fit in the voids of the sub-seat on the 2021 model year. In fact the section of heater hose I ended up using was only slightly wider than the 3/8" band clamps required to hold the hose in place. The seat's rib voids are only that wide. I didn't even pull the module.
I used 2 pieces of hose and two clamps positioned differently than the TSB would have had me do it due to the seat's updates. The noise I was hearing and the movement I was experiencing was gone immediately. The repair is straightforward and takes about 20 minutes to perform. You'll need a couple of inches of 3/4" heater hose and two screw-type band clamps. Two on each side may actually be better. There is room for these above the seat module.
Now having said all that I still think these seats are noisy when I initially sit on them I hear a noise while I'm putting my weight on the seat. Adding the two additional clamps I mentioned above may or may not help here. Once my weight is on them I don't hear anything and there is no more seat shifting on corners. I'm sure I could silence this noise too but it might actually require the seat to be pulled and shimmed. Perhaps another day.