I purchased this hose reel about 5 years ago and it's given me relatively trouble free operation until a few weeks ago when it sprung a leak. I had no idea how this thing was put together and the Ames customer support is very bad. In fact, I don't believe they even make this model anymore and aren't the least bit interested in assiting you to repair it. I believe it's the product number 38828476 but I am not certain, couldn't find much info about it on the web. However, it is incredibly easy to repair and should last many years, I'm not sure why they don't make this anymore.
At any rate, I took it apart and noticed that it is sealed by 4 o-rings which had worn out, causing my leak. After some trial and error I found the right ones at Lowes (Number 557, 3/4" ID (1" OD) x 1/8" WALL)
I cleaned the assembly with a brass brush, replaced these four o-rings and it's working great again. Don't forget the waterproof plumbers grease when installing these or they wont last very long.