For your John Deere 6155R from the 6R series there are more than 190 replacement parts here, such as electrics, trailer couplings and lighting.
A modern tractor like the John Deere 6155R is less likely to be stopped by a worn shaft than by a sensor, relay or connector. The more than 190 parts on this page reflect that: alongside ball joints and starter motors there are fuel pressure and temperature sensors, oil pressure switches, micro relays and NOX sensors. There is also plenty for everything that hangs off the back of the tractor, from makers such as Walterscheid, Scharmüller, Sauermann and Wabco.
A warning on the display does not automatically mean something major has failed. A fuel pressure sensor, a temperature sensor or an oil pressure switch can be the whole story. The NOX sensor in the exhaust keeps watch over emissions, and when it fails the engine may drop into a reduced power mode until the fault is cleared.
Micro relay tip: when a function drops out and you suspect a relay, swap it with an identical relay from the same fuse box that serves something else. If the fault moves with it, you know for certain the relay is to blame. When buying a new one, check the number of pins and whether it has a changeover contact, so it fits the existing socket.
For hitching up there are drawbar balls, drawbar frames and connector heads for the trailer air brakes. If you pull a trailer with forced steering, the parts for that are here too, such as inserts for the Pick-Up Hitch. A hitch that pulls heavy loads every day deserves a regular look at wear on the ball and its locking pin.
At the front axle there are ball joints and track rods. Play in a track rod shows up as vague straight line running, especially at road speed, and after replacing one the toe-in needs resetting. For starting there are conventional starter motors and gear reduction starters. LED work lights give light all round, and a lockable fuel cap keeps the diesel safe when the tractor is left in a field or at the roadside.
The type plate on the 6155R carries the serial number of the tractor. Keep a note of it, because it helps with parts that exist in more than one version. Many sensors, relays and starters also carry a reference number. Compare it with the details shown for the item and you know you have the right part.
The other tractors in the 6R series have their own pages with their own parts: John Deere 6130R, John Deere 6150R, John Deere 6175R, John Deere 6195R, John Deere 6215R and John Deere 6250R. The 6125R and 6145R belong to this series as well. For every other model of the make, go to John Deere parts.
