• Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!

JCB 512-56 Broken Axle

Makers Acres

Senior Member
Joined
Sep 13, 2020
Messages
286
Location
Los Angeles, California
Occupation
Imagineer
Well, I did another dumb thing and bought a used machine with problems. From what I can tell so far before I tear it apart, it looks like it needs a rear axle, or maybe just a rear knuckle?

It looks like just one side snapped the rear knuckles off. I found a Facebook thread from a rental company that appears to see this a lot when someone forgets to set the parking brake and lets it roll down the hill or drops the load of the front too fast and then the machine comes crashing down on the rear. I imagine with that large counterweight that is a lot of stress on these castings. To me, the castings look too small to begin with.

Anyhow, does anyone have the service manuals for this thing?

Has anyone done this repair before? I am sure I am going to get some negative responses to this, but has anyone welded one of these back together and then line bored it? I know if this was a rental company or a company machine, this is an absolute no-no, but this is a private machine for moving things around the farm from time to time. Maybe 5-10 hours of use per year... maybe.
 

Simon C

Senior Member
Joined
Jul 1, 2015
Messages
3,051
Location
Rocky Mountain House , AB., Canada
Occupation
Heavy Equipment Mechanic
Well, I did another dumb thing and bought a used machine with problems. From what I can tell so far before I tear it apart, it looks like it needs a rear axle, or maybe just a rear knuckle?

It looks like just one side snapped the rear knuckles off. I found a Facebook thread from a rental company that appears to see this a lot when someone forgets to set the parking brake and lets it roll down the hill or drops the load of the front too fast and then the machine comes crashing down on the rear. I imagine with that large counterweight that is a lot of stress on these castings. To me, the castings look too small to begin with.

Anyhow, does anyone have the service manuals for this thing?

Has anyone done this repair before? I am sure I am going to get some negative responses to this, but has anyone welded one of these back together and then line bored it? I know if this was a rental company or a company machine, this is an absolute no-no, but this is a private machine for moving things around the farm from time to time. Maybe 5-10 hours of use per year... maybe.
Maybe post some pictures for more folks to chime in.
Simon C
 

Makers Acres

Senior Member
Joined
Sep 13, 2020
Messages
286
Location
Los Angeles, California
Occupation
Imagineer
So I bought the thing sight unseen on Tuesday, and picked it up today (Thursday). I was just going off crappy pictures before, but was so excited I wanted to get something posted so I could lay awake at night thinking about the repair. I was able to drive it 3 wheeled on and off the trailer and the engine and the rest of the hydraulics appear to be good. Attached are some pictures I took a few minutes ago. And to be clear, the other chunk is missing.IMG_7561.jpegIMG_7566.jpegIMG_7564.jpeg
 
Top