Frequently adding brake fluid. Where should I first look for leak? on 2003 Kia Sedona

Just had all four wheels off, brakes checked, rt/rear cylinder replaced. (note: steel exposed on inside edge of tread on both rear tires... replaced rear tires, no alignment, yet) Having to add brake fluid every 4-5 days.

Asked by for the 2003 Kia Sedona
Look for the wet spot....................If no history of problems prior to wheel cylinder replacement start there.
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You said you have no leaks? Double check. The master cylinder is a week link also. If the master cylinder is mounted to the booster, remove it. you should not see any fluid between the two. If it's wet, it's coming from the master cylinder and contaminating the booster, creating more problems. Goodluck
Thanks. Appreciate the assist.