1970 Chevy c50 dump hydraulic pump identification

[Jmfrm]

Hello everyone. I have a 70' C50 with a dump body. The hydraulic pump was leaking so I removed it and pulled it apart only to find that I cannot find a rebuild kit for it! There is the numbers A 143003 stamped on oe housing cover and the numbers A 143 31484 on the pump housing. Does anyone have any idea who made the pumps for these trucks? It is driven by the pto and the cylinder and pump are bolted together. The cylinder acts as the or reservoir for the fluid so retro fitting a newer style pump is out of the question. I intend on machining the part I need if that's what it comes down to. But someone out there must know something about who made these, and if at all any parts are available to reseal them. Any help is appreciated. I love the truck but it's useless on my farm without the dump working.