When I try to brew a cup of coffee on my keurig b100 water leaks back into the resevoir and I only get half cups.

SOURCE: Delivers only small amount of coffee per brewed cup

this is not a scale issue, mine arrived from the factory producing only 6oz of water. way to strong for most. called the factory, scale, scale blah blah blah, vinegar untill we were blue. bored one day took the unit apart. on the right hand side there is some clear tubing which housed a one way valve, took apart and the valve was partally clogged. removed cleaned and reinstalled, this valve works best when not fully" seated" where it belongs so reinstall gently into the hose and leave it alone. I know what your thinking scale, scale scale. wrong. still only made 6 oz cups. there is a timer device on the back wall of the front panel on the right side as you face the unit. it is adhered to the wall with two sided tape. pry it off and on the back low and behold is a timer screw that changes the length of pump run time. turn clockwise with a sharp knife or eyeglass screwdriver and retest. 9oz of water. shame on keurig for not being more responsive to its customers.

SOURCE: keurig coffee maker won't draw water from the resevoir

I just got mine to work by forcing water into the pump to force it to prime. I took a syringe for a meat injector and built a gasket so it would seal over the water intake. Then I forced several syringes of water into the pump till it finally picked up and caught its prime.

SOURCE: Partial cup of coffee brewed

Call keurig customer service 1800 cup brew

SOURCE: Our Keurig only dispenses a partial cup of coffee.

Keurig coffee maker dispenses only part of a cup (about 5 ounces) after brewng one cup. Running a second clear cup (w/o K-cup) shows coffee grounds in cup of clear water. the maker will then brew a full cup of coffee. It appears that the top pin is too long and goes into the coffee after it punches through the top of the K-cup. Some of the gorunds appear to get stuck in the top pin.

SOURCE: my k cup reusable coffee

I had the same issue and found a **** fix that is working well. The issue is that the hole in the my-kcup doesn't seal to the machine so I take a square of foil and put it over the top of the closed my-kcup assembly, crimping it under the rim of the cap. This seals the assembly and forces the water through the my-kcup. It also makes a better cup of coffee because the water is all going through the grounds.