Problem with the rear of the car
 

I detail my car quite frequently and while most of the car's body panels still bead water after 1-2 months, the rear of the car (rear hatch and rear bumper) seems to always lose its protection faster than the rest of the car. I run a high-flo cat so the rear of the car is ususally covered in a layer of exhaust soot, does this eat up the sealant/wax faster?

what kinda sealant/wax you using?
I'd probably say its just the nature of hatch backs getting more dirt on the back most of the time and then losing beading properties.

the last time I detailed it was with Klasse AIO and Colinite 845, basically the winter setup.

i mean colinite 845 is like god like resistance, its probably just the fact that its a hatch back, getting lots of dust/dirt stuck causing the lose of beading, it should still be there tho, i dont see why colinite 845 only lasts 1-2 months unless the AIO is causing the durability lose.

The Colli 845 has A LOT of carrier solvents in it. Layering it over something else will more than likely affect the base layer. Aldric was also correct in that the rear of the car gets way more abuse as well. What are you washing it with?

Thanks Ken. I've using Optimum No Rinse.
I figured the front of the car and the rocker panels would get most of the abuse, but they still bead well. The rear of the car always have a layer of grit on it. I find I have to clay that area more often than the rest of the car.

the front of the car gets more abuse from rocks but aerodynamics probably assists and probably the contours.
the rear end, the rear tires hit up stuff to the rear hatch and theres no wind assisting water to go off so a lot of dust is built up instead

Yeah, what he said!