Have a 94 YJ new stock master cylinder, stock booster. Stock HP30 front with a 97 Explorer 8.8 rear with disc brakes. 4.3 ltr Vortec, 4l60e, NP231. My problem is when the suspension is in travel the brake pedal goes to the floor, at no other time does it do this. I did check to see if any hoses when pinched, nothing. I had the master replace last week beacuse the pedal went to floor after I did a huge burn out. Since then only does it during suspension travel. I was told a motor with a bigger cam would not create enough vacumm, but I would think the problem would be happening all the time. Not just during travel. Any thoughts??