I would not use them under any circumstances with brakes. They fill the bearing area with solid grease and they have a spring loaded piston to keep pressure on the grease. Invariably, the pressurized grease gets by the seal. Great for boat trailers without brakes, though, no air space at all to allow water in. If you repack your bearings once a year and travel less than 10,000 miles you should be fine, and you will not get grease on the brakes. Just my $. 02