Just purchased a non running Caterpillar 446D 4x4 with the 3114 cat engine. The ad stated that the machine was "stuck in lockout". I had it delivered to my home in OK from PA and the driver showed up without ramps so I used our loading ramp at work and now the machine is setting at my dealership lol. Hoping to get it moved before the boss sees it still setting on the loading dock. The rear hoe is down and can't get it back up so I can "road" it to my house. I Can find anything for cat 420s and 430s but nothing on the 446D. Replaced starter fuse and machine now runs great. Front loader controls work, the right side foot control for extending the hoe works. The left pedal moves and you can hear something happening but no movement. Outriggers are not even trying to move. No hoe functions at all except the extended hoe. Lockout switch on right panel lights up when locked, light goes out when unlocked. Doesn't even feel like I have any kind of pressure for the joysticks. This hoe has ac/heat, radio, and what I believe is ride control. rear hoe is down and can't get it back up. All fuses are good, have swapped all relays around to try and rule out a relay problem. Hoping that someone has a few ideas before I call CAT lol. I do believe this also has what is called pilot controls. I am not very familiar with the names of hydraulic components but I believe the "pilot solenoid valve" may be the problem. Also the side swing cylinders are unhooked and capped off. Does not have plumbing for hydraulic attachments. When machine is running, no alarms sound and no buzzers buzz.
You can Crack a hydraulic line to the hoe, use a forklift to pick the hoe up and then tighten the line back it should hold,
That should work on all attachments that are down and won't go up
Try checking pressure relief valves on the valve sections under the rear hoe controls,, if possible try checking hydraulic pump pressures.
I finally got the backhoe home. I have power to the "pilot shut off valve solenoid". With the lockout switch in the off position (allowing flow) I have power and ground at solenoid, when unplugging and plugging back in the solenoid, it clicks like it is working. Solonoid seems to get very hot quickly, as i also noticed the relays in the fuse boxes also seem to get very hot. May or may not be normal, i dont know. Is there anything that would restrict the flow of hydraulic to the shut off valve? Like i mentioned, the extenda hoe works, but no stabilizers or outriggers. Tried working front bucket and rear controls at same time to see if it changed anything, does not. At this time, i dont now have a way to check pressures. Isnt everything on the machine powered by 1 hydraulic pump? If so then my problem lies elsewhere...
Also found this hose has been unhooked for a little while.
And what are these? One on each side of the front of rear axle. They were loose and leaking. I tightened them.
As regards the implements, yes. There is a small vane pump mounted on the back of the implement hydraulic pump but that pump is only for operating the brakes. I'll send you some schematics that might help, but really you need a Service Manual to get in-depth information regarding how the implement hydraulic system operates.
This might also help you. It's an explanation of how the hydraulic resolver network operates. The Service Manual for the 446D is Cat Publication reference RENR8700. At a quick glance I don't see any up for sale on eBay or similar.
Thank you Nige. I found one on eBay for $350. Quite expensive but I'm sure it is well worth it. Will be purchasing it today.
A new one would be $900, just so you are aware. You got a good deal at $350 provided that the manual is complete.
Waiting on a manual. Does anyone possibly have a schematic of the rear hydraulics? I have no clue where to start. I pulled the pilot solenoid and it is functioning as it should. When i removed the solenoid, fluid was slowly gravity feeding itself. Is there another solenoid i should be checking? Also keep reading about spool valves, should i be checking spool valves? have no idea what they even look like lol.
Attached the hydraulic schematic for the whole machine.