Noticed some black specs in the water from the dispenser. Installed a water filter on back line between water supply and fridge. Didn't clear up problem. Noticed there were some black specs in the internal water storage line inside the fridge under the crisper. Don't really know what's in-between the two lines (inside the unit) that could cause this but hope exchanging this storage line (with AP3186680) will do the trick. I guess my question is: how difficult is replacing this line? Also, should I look for another cause also? This unit sat since 2007 or so without use. Thank you. I attached the part diagram. It is part #810 in this diagram.