I have been recently getting my 88 RX7 TII that I purchased a couple months ago (sat for 10yrs from previous owner) back on the road. Finally got it started and attempted to take on a test drive the other day after installing new brakes, rotors, and calipers (front and rear) on it. When i was atttempting to bleed the system at first with car off and and everything was working fine. Then started the car up to feel the brakes, as I pressed on the brake pedal car began to increase RPM and pedal began to real correct. Let car idle then pressed pedal but it was soft and went to the floor. Bled system with car on this time, no air in any of the lines what so ever, bled rear calipers using the upper bleeder screw. As i would rev engine i would loose pressure in pedal feel for a short period of time then if i stop reving engine i would pedal would get stiff and if i let it idle for short period of time the pedal would go to ground.

Leaning toward the possiblity that there could be an issue with the power brake booster.
Just wanted to see if any one has ever had this issue before i spend more money on this car. Take in mind that this car had not run or been moved in more than 10 yrs.

Thanks in advance for any help.

 

Probably the booster as you surmise, but why screw around?
You've already renewed everything else, do the booster and MC and be done.

 

Going to end up having to order one later on in the week. Just hope after replacing both items that will solve the problem. Checked the check valve first to make sure that wasnt the issue.