Hi I have a Cat 930G wheel loader that wont lower the bucket without lifting the bucket up further sometimes you have to lift the bucket up a couple times before it will let you lower it. it does the same thing on the forward tilt. it does put load on the engine when you try to lower or tilt forward bucket. any ideas on what could be the problem?
First thing to do is post a serial number.
Serial # CAT0930GJTWR01747
One of the Cat resident experts should be along soon to help. Posting the s/n just expedites the process. Has anyone checked the forks/bucket rocker switch ?
I suspect that the load check valve may be sticking in the bore. There is one for bucket, and another in the next section for boom. You didn't indicate how many hours on the machine. I circled the where, and pointed to the suspect area, BUT IF YOU DON'T KNOW HOW TO RELIEVE THE RIDE CONTROL AND BOOM PRESSURE, do NOT remove that item for inspection. There is some serious pressure that can remain in the boom circuit until the ride control is completely discharged, and it should go without saying that the boom needs supported or fully lowered, too.
According to SIS this machine was not built with Ride Control, but that's not to say it could not have been installed at a later date. Just as a check, does it have the Ride Control switch (#1) on the LH panel.? See the attachment for releasing the pressure in the Hydraulic System - this does NOT include the Ride Control which is a separate procedure.
I did pull the check valves and clean them and put them back in and it didn't make a difference , I couldn't see anything obvious that was wrong with them but that doesn't mean that there not the problem. The boss doesn't want to spend any more time on this machine so I guess that's it. I Appreciate all the help and info! Thanks and Happy New Year!