Hi, I am trying to figure out what to do to restore proper function to my 4 in 1 bucket on my cat 428d backhoe. It used to up tilt / scoop independently but recently the upward tilt function only works when the bucket is being raised or lowered. It down tilts / dumps independently. Any help as to were to start to find the problem would be greatly appreciated 7e7702 8e7681
The place to start is looking at the linkages between the handle and the valve, I can't tell you what to look for but should be obvious on the up tilt action. If you don't find anything, I guess you'll have to wait for somebody who actually knows something about Cat backhoes valves. This doesn't sound like it has anything to do with the 4 in 1 function, does it? and were there any other symptoms that showed up around the same time, bucket dropping? overloading? full moon???
This might be a long shot but on my 436b the valves have a pencil valve inside the valve that tells the hydraulic pump when it needs volume. If it works only when another function is applied one of the pencil valves might be bad. I had this happen on the backhoe valves as well as the front valve body. They can be changed in the machine. I'm just guessing the newer machine still has this.