Hi - Lately, or it seems like this coincided with cold weather (probably coincidence?), that i've lost some brake pressure. I'm not having to push the brakes to the floor, but it's definitely lost some pressure. The master cylinder was replaced about 2 years ago, so I'm not sure if it would be that. I checked the brake fluid and the reservoir only appears to be at the minimum mark on one side of the two sides?, which I thought was odd. Are both sides suppose to be at the min mark, or just one side? I do not notice any leaks? Before I take it to the mechanic, I was hoping for some insight. Also I was searching the threads for filling brake fluid, but I only read about flushing. Is it okay to add fluid? I takes dot 4, which when i went to autozone they only had what was a combination of 3 and 4. Would the mix be okay as well?

 

Pads wearing down will cause the level to drop. It's OK to add brake fluid, but when the level drops enough to turn on the brake warning light it is often an indication that the pads need to be replaced, and not necessarily a leak. Check for both. If you just keep adding fluid to keep the level around MAX or to turn the light out, you lose this warning about worn pads.

Cold weather should not be a factor; your soft pedal could be from the master cylinder going out again - it happens - air in the system, which would also indicate a leak, or a caliper sticking, which is more likely to happen when the pads are almost worn out because the piston is almost fully extended.