65 K-10 Locking Hubs?

[67JimmyMO]

I was wondering if anyone knew of replacement locking front hubs for my 65 K-10?

Currently have the Hub Lok models and having trouble getting one of them to lock, even after disassembly, cleaning and lubrication. I don't see any differences in the parts between the 2 hubs. I thought maybe the springs might be weaker in one so I swapped them, didn't help.

I found some pictures of some pages from a manual here:

https://67-72chevytrucks.com/vboard/...d.php?t=557263

that show the Hub Loks. Does anyone know which manual these pages are from? I PM'd padresag but it looks like he hasn't been active for over a year.

I've attempted to search the forum and have found mention of Selectro/Mile Marker being a possibility but they seem to be out of stock/discontinued if I am looking at the correct part.

Any thoughts or suggestions are appreciated.