sounds like you are having the same problem I do with my TR6....I replaced everything up front ,calipers, rotors , pads hoses, still had 'bad' braking...replaced rear brake shoes ,adjusted...took it to shop, b/c it was still not braking right...if I hit the pedal fast (like a panic braking) pedal was up high and firm, if I hit t slow pedal slwly goes t the floor, I could pump it up, but a slow braking it would go down...I told mechanic I thought it was a bad booster...they tested it ,said ,no a bad MC, they replaced it...I picked the car up...it was the same, brought it back...they said , maybe a bad MC (the manuf has 25% return on these!), replaced it for another, picked car up, still the same, now they tell me I need a new booster! LOL...will order one monday , we`ll see... Does Lucas make boosters?? LOL
