Y26 pivot bearing

Hi Everyone. Shot in the dark but hope someone may be able to help.

I have a Y26 that has developed alot of movement where the rear triangle connects to the frame.

Does anyone know what size the bearings are so I can order new ones before removing them?

Any technical diagrams would also be useful

I have spoken to Trek and their files don't go back to this model so they couldn't help.

Thanks in advance for any help that can be given.