Need electrics, steering and front axle parts or lighting for a John Deere 2520? The 2000 series has its own page here, with more than 140 parts on it.
When a John Deere 2520 refuses to start on a cold morning, the cause is usually in one of two places: the starting circuit or the fuel supply. This page covers both, along with pistons, bushes and gaskets for a full engine overhaul. Altogether there are more than 140 parts here from GRANIT, HELLA, VICTOR REINZ, MAHLE and MANN-FILTER that fit this tractor.
For the 2520 there are standard starter motors as well as gear reduction starters, plus separate solenoid switches. The circuit is covered by changeover relays and micro relays, and there is an oil pressure switch for the warning lamp on the dash.
Before swapping a starter motor, check the battery terminals and the earth cable to the block. A corroded connection gives exactly the same symptom as a worn starter: it clicks but will not turn over. Measure the voltage at the starter while cranking. If it drops sharply, the fault is in the wiring.
The fuel system parts include a feed pump with its seal, a filter bowl, injection nozzles and a vented tank cap. A blocked vent in the cap creates a vacuum in the tank, and after a while the engine runs short of diesel even with a clean filter.
If you see water or dirt at the bottom of the filter bowl, drain it before it reaches the injectors. After replacing the filter or feed pump, bleed the system with the hand primer until diesel comes from the bleed screw without air bubbles.
If you suspect an injector, have it pop tested on a bench. Black smoke and a rough idle often point to a nozzle that dribbles after injection. Always fit new sealing washers under the injectors when they go back in.
Going further, you will find piston and liner sets, bushes, O-ring sets and gaskets, for example for the exhaust and the thermostat. Replace every gasket you disturb when opening up the engine, however good it still looks. A reused gasket is the classic cause of a leak that only shows up once everything is back together.
The type plate on your John Deere carries the type and serial number. Faster still is the reference number on the old part, especially for starter motors and injection nozzles, which come in several versions. If another John Deere shares the shed with your 2520, its parts are on the John Deere parts page.