Jaguar E-type spare parts do not offer a repair kit for the belt tensioner pulley. It is only proposed to buy back the complete pulley.
I offer you a small tutorial which allows you to replace only the bearing part and thus refurbish your pulley:
1- Remove the tensioner pulley by unscrewing its nut.
2- Push on the bearing on the side of the axis with a press or a bench vise. In the photo below you will see that I was able to easily take out the bearing using two sockets, one big to hold the roller and a small one to push on the bearing. You will see that the protective sheet metal pad of the bearing (radiator side) will come off when you push. The roller is 23 mm wide, and the bearing is 24 mm in diameter and 21 mm in wide.
3- Fit two sealed and standard bearings of dimensions: external diameter 24mm, internal diameter 8mm, length 10mm. For your information, I inquired, the sealed bearings withstand about 28,000 rpm/min and 120°C (which is well above the operating temperature of the roller). The goal is to mount them side by side by aligning the 1st bearing on the face of the roller on the engine side. For this, you can for example push (in the same way with a bench vise or a press) with oil the 1st bearing from the face on the radiator side, then the second bearing on the same side (which will push the first at the same time).
4- Next, find a 5/16 UNF bolt of at least 35 mm length and a small width washer allowing the roller to be slightly spaced from its mounting bracket.
5- Then firmly tighten, with a shakeproof washer, the roller on its bracket. If you have the motivation, you can make an axis conforming to the origin with two flats to block the axis on bracket. But with a single bolt it goes very well.
Technical advice Q&A