Hello everyone, I serviced my brakes on sunday, everything went pretty smoothly other than a few things: 1. When I went to service the rears, I forgot that you need the brake caliper tool to retract the caliper piston. I tried using my Knipex Cobras to spin it, but it just kept spinning. I eventually rented the tool and used it on both. The left rear caliper was obviously sticking as it had a lot of corrosion on it from what I assume was extra heat, and the pads had much more wear than the other side, and worn unevenly as the outer pad had like 3mm left and the inner probably had 6-8. 2. When I finished, I jumped in and fired it up without thinking to pump the brakes back up like an idiot and the pedal went to the floor. I had no brakes at all and drove into the gate in my driveway, lol. Now I have no brakes. I initially thought that maybe I had damaged the seal in that stuck caliper from spinning it and it was leaking. I went to the yard this morning and picked up both right and left rear calipers with the intent to swap at least the rear left, as it was clearly toast. Both boots were pretty sticky when I retracted the pistons, the rear left dust boot moved around a lot and actually came out of the groove on the piston and possibly the caliper as well. When I reassembled it, it seemed to be OK. That's why I originally thought it was a caliper issue. I pulled it onto the street (almost crashed again) and left it there over night. This afternoon, I rolled it back down the driveway and found that I had some brakes but I had to pump a lot, which is a classic sign of a bad MC to me. I also didn't see any brake fluid leaking from the rear brake calipers when I moved it. The MC is two or three years old. Everyone knows not to push the pedal to the floor because it can tear the seals on an old MC. I'm not sure that there would be that much junk built up in there, because I've only put about 10k km on it since the MC was replaced by a shop in 2016 or 2017. I was under the impression that this would not cause the MC to fail instantly like it did to me. I've read that it is possible to damage the seals in the MC by pushing the pedal to the floor and the seals "rolling" over and not sealing anymore. Is this possible? Because I'm pretty sure that's what I did. What are the diagnonses for a bad MC? I'm sure there are tests I can perform before I go out and buy a new MC. A shop replaced my MC and booster because the brakes on my car would barely function when you first started the car. The pedal would be hard but the brakes would barely function which is really scary when you are trying to back out of a parking spot in a parking lot. I've never replaced a MC before but I am definitely going to try because I have a second vehicle that I can use in the meantime. I have line wrenches, but I need a MC bleed kit too, right? I'm also having trouble finding the correct MC for my car: 2003 Jetta 1.8 auto with DSC. Rockauto only differentiates between DSC and non-DSC models. I'm not sure If I can use the MC intended for manual trans models as it has a port for the clutch that I don't need. I was wondering if anyone knows if I can use any old MC for a MK4 or if I should go to a parts store and get one that is matched to my vin. Thanks.