Home / Lawn & Garden / Parts / Zerk Grease Fitting, 3/8-in 539115638 Zerk Grease Fitting, 3/8-in 539115638$2.49 Price may not be up-to-date. In Stock View Product Part Number: 539115638 Brand: AMERICAN YARD PRODUCTS Seller: Sears PartsDirect Categories: Lawn & Garden, Parts Not Returnable Description This grease fitting (part number 539115638) is for lawn tractors. Grease fitting 539115638 feeds grease to a bearing to keep the bearing lubricated. Wear work gloves to protect your hands when installing this part.