Replacing RV components like ABS disc brakes, drum brakes, or wheel cylinders isn't exactly rocket science! And although you should always hire a mechanic if you're not sure what you're doing, fully trained auto enthusiasts could do it themselves in 2-3 hours tops - including an oil change at the same time for good measure! At least one company offers a free installation service if required... so check their website and call before buying any spare parts to make absolutely sure about their return policy!