so recently i have been working on my 88 comanche pioneer and still can't seem to figure out why my clutch will not hold preassure. this all started last spring when i had to park it for that exact reason. during the down time i did a full BA10 to AX15 conversion. my set up is as follows; 88MJ body and engine, 98 XJ front and rear axles, 98 ZJ rear disc brakes, aftermarket crossmember and trans mount, AX15 trans and T-case from 92 wrangler. and now for the clutch set-up, replaced master cylinder last spring, new clutch, re-surfaced flywheel, new internal slave, new clutch line, and new brass clutch line fittings. my problem is as i stated before the clutch will not hold pressure for very long a few days at very best, has been bled many times. nothing leaks that i can tell. could this be a bad master cylinder (i know this can happen) or am I missing something critical? please help, i love my truck and don't want it to just sit there.......