Crate and potty training

Question
Barney is my 5 month old pug (just last week he was neutered) - I got him at 2 months.  Almost immediately I crated him and he was doing super - until about over 2 plus ago he started to pee in the crate at night and then randomly peeing on the floor after taking him out.    Every other day or so he pees in the crate while I am at work.  before I leave for work - I take him out twice.

Answer
That is strange.  The vet did do a complete physical before neutering?  I would think one would put off the neutering until anything like a UTI was cleared up.  When you take him out, do you make sure you walk him around to stimulate elimination? Try taking the water up at 7 PM.  If it is a behavior thing, it may improve as the hormones work their way out of the system following the neutering.  By the way, thank you for taking that responsible step as a pet owner.  

While you are waiting for some of the above to take effect, you could put a grid in the crate.  It doesn't solve the problem, but makes it easier to cope with it.  They are available with the crates, but expensive and hard to find. A piece of closely spaced wire closet shelving from a home supply place is cheaper. I am now using a plastic vegetable bin with plenty of holes drilled in the bottom.

You may be interest to know I recently visited an assistance dog school.  They breed Pugs to train to assist the hearing impaired.  They are plenty big enough to do that, and the small dog live longer and are cheaper to keep.