This sealing washer sits between the baler plunger and the bale-chamber floor, preventing fines and crop residue from migrating into the plunger-guide system. It compresses against the mating face under the plunger’s clamping load, forming a barrier that keeps the guide rails and bearings free of abrasive dust. A worn or missing washer allows debris ingress, which accelerates guide-rail wear and can cause the plunger to drift off its stroke axis. The washer’s large outer diameter distributes the clamping force evenly over the sealing face, reducing the risk of localized extrusion. On reinstall, ensure the sealing face is clean and free of old gasket material.