4B1397 4F5003 Idler Pad Assembly Fits CAT Fits Caterpillar D7 D8One New Aftermarket Replacement Idler Spring Mount (Pad Assembly) Fits Caterpillar (Fits CAT) D7 and D8 Track Type Dozers This aftermarket replacement spring mount (idler pad assembly) is part of the front idler recoil and track adjustment system on Fits Caterpillar (Fits CAT) track type bulldozers. The spring mount cushions the front idler assembly, allowing it to absorb shock loads and move forward and back to maintain proper track tension during