Well, I think I found out what it was. I was sure there were no leaks...but I noticed a small drop of fluid at the bottom of the drum on the left front. I thought it was where I had dripped or spilled fluid, but I wiped it clean and it reappeared in a few minutes. Ergo, I must have a leak at that wheel cylinder. That would explain pulling air into the system when I vacuum bled it.
Next thing will be to pull that wheel off and check it out.
I'll post a follow up once I find out. Thanks!!!
