I've put Freddy Fenders on 2 of my 5 bikes. It does involve a fair amount of time adjusting the stay lengths to keep the fenders from rubbing. If you are having trouble with your brakes, check that they are not actually hitting the fender. If the fenders are wide on some brakes I have had to file little notches to improve the clearance of the brake arms. If the brakes aren't hitting the fender, look at how they are mounted. Most of the front fenders get mounted on the front brake mounting bolt. If the shop had to take the brakes off to do this (most likely) the brake might not be properly centered. If that is the case, they should fix it. It doesn't matter if it is your car or your bike; when it comes out of the shop, the brakes should be working.