Maintaining a John Deere 4520? Pick from more than 40 parts on this page, with lighting, electrics and steering and front axle components in one place.
John Deere 4520 parts on this page cover more than 40 items, from a MANN-FILTER fuel filter to the hinge on the cab door. Further tractor parts for the 4520 come from GRANIT, HELLA, AKS-Dasis and BOSCH.
After changing the fuel filter, bleed the system. Work the hand primer until the diesel coming out at the bleed point shows no more air bubbles. Skip that and the engine will crank for ages or not fire at all.
The tank caps on this page are vented, and that vent needs to stay clear. If it blocks, a vacuum builds up in the tank and the engine dies after a while even though there is plenty of fuel left.
Oil seeping between the engine and the clutch housing usually points at the rear crankshaft seal. Since the tractor has to be split to reach it, it makes sense to inspect the clutch while you are there. Press the new seal in squarely with a proper seal driver, never with a few taps around the edge, or it will leak again straight away.
The brake light switches here are oil pressure operated: they switch the brake light on as soon as pressure builds in the brake circuit. If the light stays off while the bulbs are fine, the switch is the obvious first check. When fitting a new hydraulic pump, change the oil and filter too, so dirt from the old pump does not end up in the new one.
Start by checking the data plate to make sure you are working on a 4520. Thermostats, gaskets and seals often carry a number on the old part or its packaging, so compare that with the new one. With a crankshaft seal, position matters too, as the rear seal is a different part from the front one.
The John Deere 3120 has its own page with the parts that fit it, which helps if both tractors are on the farm. For every other model, visit John Deere parts.
