Complete Success (for the 2nd time)
I spilled a small amount of water (probably less than 1 tsp) on the MacBook. From that moment on, it only worked when plugged in and the diagnostics told me I needed a new battery. I have complete Apple Care coverage but not the new Apple Care Plus (which would cover the spill) and it was no help at all. The people at the Apple Store told me it would cost approx. $800 to fix (and get no warranty). So, I came (came back after a prior success installing a new SSD in my old iMac) to iFixit.
I'm not the best with mechanical things. But, this really wasn't hard and the directions were excellent. There are illustrated pictures that looked (more or less) exactly like what I found when I opened the computer up. My machine's internal workings had small variances from the illustrations but they were very close and it was easy to get the idea. I had no issues at all putting the new battery in. I used to solvent and it was easy and worked well. Complete success - the first time. It works like it is brand new and Apple diagnostics indicate there are no problems.
(1) Leave a trail of mental breadcrumbs. Once the battery in put in, there are no more instructions on how to put everything back together. Just pay attention when you unhook the connections and follow the instructions in reverse when putting it all back together, (2) Be careful with the solvent AND THE GLOVES. I was very careful and wore the gloves and goggles. BUT, when I filled the syringe with solvent for the last time and set down the bottle of solvent, my glove - oh so briefly - stuck to the bottle of solvent. I realized that as I pulled my hand away, the bottle of solvent moved, and a small amount of solvent jumped out and right onto my fully exposed computer. But, before I could even get it up with a paper towel I had nearby, it had evaporated. Almost instantly! I still thought I was done as I cursed the gloves and didn't have high hopes at that point. But, no harm was done. Either the instant evaporation or luck saved me and I'll take either one! My advice - if you're even a tad clumsy (like me), set the bottle of solvent in a place where you can knock the whole thing over and do no harm.