86 4wd sr5. Newer trans and clutch. Clutch master cylinder had small leak. Replaced and bled. Ok for couple of days then started slipping. Bled again and same problem. Took it to a shop that had a bleed pot and same thing. Worse on warm afternoons. Clutch pedal gets real stiff. ???????
Check the pushrod on the slave. It should have some free play. You may even be able to here the motor start to stall on the trust bearings with the clutch in. Usually if it has air in the system it gets better after driving and is hard to get in gear. It wouldn't be slipping. Even the slightest bit on contact on the fork with the clutch engaged can be problematic.
Original message I figure will be best to reply here. Have about .4 play when cold, could only achieve that much by adjusting pushrod counter clockwise to the maximum adjustment will not turn anymore. After the clutch starts slipping lose all play and pedal is stiff. Next morning play is back When you are bleeding the slave are you doing it unbolted from the bellhousing and pushing the rod back? Thinking how maybe bleeding may have an effect. Maybe not doing so didn't allow the rod to extend all the way and as the system fills it can't push back.
When the clutch gets hard make your one man bleeder with the bottle and see if you can push the rod back. I'm about out of ideas though and would start to suspect a nfg slave or master if nothing changes. Maybe someone will chime in with the solution now that more things have been pointed out.