My 08 had the same problem after I had a LS installed in it. Turn out the O-ring that sealed the mater cylinder to brake booster was not installed when put back togerther. wasn't really a problem for me as I installed my ARB air compressor back on it when I brought the jeep back home, so I just put a new o-ring back on. the o-ring is 1-7/8 ID if yours is missing or broken.
you don't need a vacuum pump to check and see if it is working. just run the engine for about a minute and shut it off. then pull the check valve off. if there is no leak then you will here the air rushing into the booster. It may help to pull it off first before you start and spay the end with some silicone spray, it will help seal also. If you pull the hose off the check valve nothing will happen, took me about two trys before I realised this and then pulled the check valve to booster off.
89 Wrangler, 2.5L TBI, D30 Truetrac 4.56 gear front, Super 35 4.56 gears rear, 31" BFG Mud's, 15x9" weld racing pro-stars XP's, 2.5" rancho and 1.25" shackels, superior axles. rear wilwood disc brakes
2008 wrangler x unlimited. Stone white. Motech 5.3L LS Chevy