126: Brake Pedal Hard on start

[300sd2000]

Hello,

I couldn't find the answer for this searching so I will post a new questions.

My 300SD is having problems with a stiff pedal after 2 times when leaving the driveway after being parked. The pedal is good intially, but then becomes hard after 2-3 tries. Seems much worse than the other (older) 300SD.

Here's what's been done:
1. Vaccuum Pump - dealer replaced about a 1 year ago so I don't suspect it currently. Getting about 20" Vaccuum.

2. Brake Booster and Master Cylinder - just did this myself -- using parts from fastlane. Didn't help much with the cold start problem, but car stops better once running. Brakes bled using Motive Bleeder. Valvoline Syn Dot 4

3. Vaccum Leak testing - swapped the entire booster line from the other car - no help. SO hose and check valve must be okay

4. Leaks in lines - I can't seem to hold good vaccuum on the brown (IGN?), or red/green (AC?), or the door lock. The white (TRANS) line is holding 15" vacccum.

Question#1: Is the brown line supposed to hold vaccuum once car is on? Car shuts off fine... door locks...working. Trans, shifts fine. EGR - temporarily bypasssed for diagnostics. A/C Vents - working, although I had leaks in the dashpots last year.

Question #2: Could leaks from these "small" vacccum lines cause the pedal to become stiff. Has anyone thought of putting one-way check-valves in on these auxillary lines?