Hub Keeps Falling Off My 530 WFE!

Hello! My terminology might not be correct as I am not very mechanical, but I have a 530 diesel with WFE and FEL. The previous owner had the front axle extended a little bit but I've had no problems with it for the past several years. Earlier this summer, I was mowing with a brush hog and hit a groundhog hole, and the front axle broke at the extension. A car / truck mechanic friend took it into his shop and I provided a separate and complete wide front end that came off of my 350.

He said that it wasn't exactly the same size, but took the left side (extension, spindle, wheel, hub, etc.) from the spare WFE and slid it into the existing axle tube. When I got it back, I noticed that the left front wheel and tire were wobbly, and after some more mowing, the front tire and hub came off of the spindle. He brought another hub from that axle and re-installed it. I mowed for about 3 hours in Direct 1st or 5th gear, but when I turned to the left again, this one popped off as well.

Is there something unique about attaching the hub to the spindle that we're not aware of? Or do I need to find an axle or left side extension that's exactly the same size? I don't know whether to call him back or just go to someone else, but I'd like to know if anyone here knows of a reason that this has happened twice. He's a good mechanic, but he normally works on cars and trucks and not a lot on Case tractors.

Thank you for any advice / knowledge / opinions you can share!

Hard to offer advise when you don't show or tell us what your guy used to replace the axle tube and hub. For all we know the hub may have came off a Essex Tri Star, and we all know that they are lighter than Case parts.
You better find the correct parts and fix it wright.
Loren.

Is the nut still on the spindle? If it's the left side, it might be as simple as a missing cotter key. Wheel rotation will tend to unscrew the bearing nut.
Another thought is a missing washer between the outer bearing and the nut.

Lee, any chance as others have sent of sending some pics,would help us. But to me, I would try to salvage what broke, but I have no idea either how it looks.

Pictures might solve your problems my friend