After reconditioning and replacing both front calipers (due to split boots) and replacing front brake hoses (due to cracking) on my 240 I bled them according to Haynes. All 6 nipples bled OK so fluid was expelled from both brake circuits and pedal is firm. I did not note if the same volume of fluid was expelled from each nipple. However during bleeding fluid was taken from only the front reservoir (closest to the engine). No fluid was taken from the rear reservoir (closest to the firewall). THe level in the rear reservoir did not drop and the fluid remained its old "contaminated" green-black color.
This problem has just prompted my memory that for some months now the front reservoir has been half inch below full as the pads wear, but the rear cylinder remained full.
My stopping seemed OK so I guess both circuits were working. But since I dont drive fast or brake hard maybe its not possible to tell if only one or both circuits are working? With only one circuit stopping distance is doubled?
Also replaced pads and noticed some wedging of pads (say 2 or 3 mm difference in thickness between top and bottom of pads. Dont know if this is normal or if different circuit pressures applied to top and bottom pistons. Brake failure lite has never come on until after vigorous bleeding. (The FAQ details fixing/resetting the switch)

sutherml in Adelaide, Australia (where some brake parts cost 2 to 4 times the prices in America!)
1979 244GL at 518,000 km