Looking for info about Walker Roll-A-Car No. 785

[ski42]

This floor jack has been in our farm shop over 40 years now and had been my grandfathers. One of those tools you just use and don't think much about I guess. Hadn't used it in a bit and when I went to use tonight would not hold load. I'm looking to get it working again and figured would probably be worth giving it a proper restoration. I believe this is a Walker Roll-A-Car No. 785 3 3/4 ton jack. I have been trying to find some more information on this but really haven't found too much info or photos other than a sales ad from 1937, where it was called "Senior Hydraulic Roll-A-Car No.785............$55.00" and what I have looks like the photo in the ad. Any info would be greatly appreciated. Thanks