Honda Repair: 1994 Honda Accord brakes, rear drum brakes, honda techs

Question
QUESTION: I have a 1994 Honda Accord LX no ABS, started getting a soft pedal, all brakes, calipers, pads, rotors, drums, and shoes were replaced last fall. No all of a sudden had a soft pedal. No leaks assumed master cylinder replaced with new mc bench bled and installed then bled system. Pedal is hard with vehicle off but soft with vehicle running and goes to the floor, vehicle brakes and stops but pedal never went this far down. Soft pedal was intermittent before replacing mc until the other day when it was constant.
Thanks

ANSWER: Robin, since you have replaced virtually everything in your brake components try replacing the brake booster. This is located on your firewall behind your master cylinder. Kinda a black, flat pancake looking thing. There should be an air hose going to it as well which you should replace.

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QUESTION: As I understand it the brake booster is a diaphragm to assist in braking and is helped by vacuum, I have no other engine issues or rough running to indicate a vacuum issue. Also the way the booster works if it was failing or going bad it should be a hard pedal not soft correct. I have also talked with a few Honda Techs and most said the brake booster usually doesn't go bad. I guess I am just looking for something other than the booster or a bad line but as you said its all thats really left. Just weird that the soft pedal that goes to the floor would be a result of a bad booster which is used to aid in the amount of pressure required to be applied to the pedal during braking. I guess I will bleed the entire system again and look for a bad hose or line first before spending the $200 plus to replace the booster.

Answer
Do you have rear drum brakes? Did you replace the rear wheel cylinders? Those are notorious for leaking. Also, it is not uncommon for an aftermarket master cylinder to be bad. Inspect all rubber lines going to the brakes then inspect all hard lines throughout the system as well. There has to be a leak somewhere you pedal should be firm not spongy. Was the system bled properly?