A spigot bearing, also known as a pilot bearing, is a cylinder bearing that supports the transmission input shaft and fits inside the crankshaft. It is located in the centre of the engine flywheel or crankshaft flange. The spigot bearing absorbs vibrations caused by the crankshaft and input shaft rotating at different speeds when you press the clutch pedal.
How does it work?
The pilot bearing supports the opposite end of the transmission’s input shaft, which is critical to the clutch’s operation. This bearing allows the input shaft to stop spinning and shift the car’s gears. Some front-wheel-drive cars may not have this bearing because the bell housing is shorter and the input shaft can be supported within the transmission without the need for the additional pilot bearing support.
When Does It Go Wrong?
There are a few things to look for if noise is coming from the bell housing area. Begin by taking the vehicle for a test drive. With the transmission in gear and the clutch pedal pressed to the floor, listen for noise. With the transmission in first gear, release the clutch. Noise indicates a worn release bearing or a worn pilot bearing in this situation. Keep the clutch pedal pressed to the floor and the transmission in neutral to isolate the two. If the noise continues, the release bearing is faulty. Alternatively, if the noise has gone away the pilot bearing will be at fault.