Just bought this used 2012 Cat 257b3 with 4500 hours and it seems to have an issue with turning. It will sometimes turn good and then suddenly either not turn or turn very slowly. Runs forward and backwards just fine. Any ideas?
Bucket and moving machine is no longer working now either. Fires up fine but hydraulics not working.
Serial number please
*CAT0257BPB7H01275*
Checked fluid levels at all?
Fluid levels are good. Just below max line on gauge
Do you have any warning lights on the panel.?
Negative. No warning lights
Open the rear engine cover and fire up the engine. Does the radiator cooling fan start spinning immediately.?
The fan does not turn on when fired up
In that case it is almost certain that the coupling between the engine and the hydraulic pumps has failed.
Do you happen to know specifically where the coupling is located? Thanks for the help
Between the engine flywheel and the hydraulic pump. There appear to be two schools of thought regarding replacing it. One is to remove the engine and pumps as a unit and split them on the ground (this is the way the manual shows), the other is to pull the pump in the machine and replace it that way. I’ll leave it to others to comment which method they prefer.
Is there a way to check before removing?
Unfortunately not.
What would cause it to only halfway work as far as turning but forward and backwards fine then drop off? Just the coupling barely hanging on until failure?
Likely. If the fan isn’t turning then the likelihood is that the pump isn’t turning either.
What is the fan driven by?
just a little more info: - there was already a small leak from somewhere underneath. Not sure where it was coming from. Could it be that air got into the hydraulic system and stopped working?
One of the hydraulic pumps. Possible but I wouldn’t have thought it likely.
Could it not be a relay/fuse?
When you first turn on the key do all the warning lights on the panel flash during the self-test, especially the exclamation point.?
No not at all. I’m convinced it’s the coupler like you said. I’ve contacted a few CAT mechanics and they’ve all said the same. Looking for a service manual now
Maybe I was not clear. When you first turn on the key (before starting the engine) the warning light panel should perform a self-test. All the warning lights should flash (to prove that they are working) and the beeper should sound for a couple of seconds. If that doesn’t happen it is usually the result of an electrical problem that needs to be addressed before proceeding further.
Pulled the engine and this was loose inside of the flywheel. (Sprocket that goes over the hydraulic pump shaft) This was the issue. The adjustment screw worked its way loose and the sprocket loosened up as well and fell off of the shaft into the flywheel. Put everything back together and worked beautifully. Not sure what the proper names of the pieces are but hopefully this will help someone else in the future.
Good job. It’s not unusual for that screw to come loose BTW but I didn’t want to suggest that as the cause of the problem just in case the nylon coupling was trashed.
Yeah I put a little dab of blue thread locker on it (per specifications) and called it good. I also noticed that it wasn’t torqued to the right ft.lbs because the lines that were marked were off almost a quarter inch. The torque spec for that is 75ft.lbs. for anyone wondering.