.........I recently replaced the master cylinder on my 88 runner but after a few days the peddle got spongy and needed to be pupmed to stop. I re-bled the system and it worked great, rock hard but the the next morning the peddle went almost to the floor after starting it up but stayed hard all day. What would cause it to be fine all day but need to be pumped the next day at start up. Every day, pump it at start up and it's fine all day?>?????? Thanks for your time.............TIM

 

Sounds like you still have some air in the lines and possibly need to bench bleed the MC. Did you bleed the LSPV as well when you replaced the MC?

 

How were you bleeding the system?