We went this morning and no one could tell us where to find the 867 bus station.

Apparently no more bus 867, but 936 permit to go there. Someone said it takes about 4 hours... I dn't know, will test tomorrow

I went few days ago in the 867. You should take the subway to the Dongzhimen station. there, take the B exit. The building near the exit is a bus station. Do not enter there. You should go outside the building in the clock wise direction, that is, the building in the left hand side. Then, you turn to the left, and you will see lots of buses stopping at that street. Follow in that street, and after a few minutes, you will se a park lot with more buses. There you should take the 867. So as a summary, the Dongzhimen bus station is between the outer bus station (where you take the 867) and the exit B.
They departure at 7:00 and 8:30. The other way round is at 14:00 and 16:00. It costs 16 RMB single trip.