My 1971 240 has been rebuilt from the ground up over the last 6 years and ever since i put it back together it has had poor brake pedal feel. The problem seems to be with the brake booster as the pedal goes down the first 1/3rd very easy (but without much braking force to the wheels)and at 2/3rds of the way down it suddenly stops. At 2/3rd down the pedal is rock solid but it feels like the booster is doing nothing. The calipers / wheel cylinders / master cylinder are all rebuilt units and brakes are definately bled properly. I have tried three used boosters with no success. This last booster holds vacuum as per factory specs under both braking and non braking conditions. Please help - running out of patience.