I recently acquired a 963 CAT track loader (series 21Z02206) from Arlington, Texas, to use in a marble quarry in Mexico. Initially, all basic functionalities were tested and appeared to be working fine. However, on the second day of operation at the quarry, the machine failed to run. Upon inspection, we discovered that the synch cut-off valve (9J8553) was broken. Unfortunately, we were unable to find a new replacement part, so we are currently awaiting the arrival of a used replacement. Our primary concern at the moment is understanding what may have caused the valve to break, in order to avoid the same issue occurring in the future. We would greatly appreciate any expertise or tips on this matter. Thank you.
freezing or over pressure is the only thing I can think of being from Mexico that leaves out freezing
See the illustration below of the HPCU Case. Check the two relief valves #45 & #50 (LH & RH) for any signs that they have been recently tampered with or if the adjustments of the two valves are noticeably different from eash other. What type of oil are you using in the transmission.?
Thanks, I also think it's definitely not because of freezing. I still haven't had the time to check the relief valves but will do soon. I also believe I'm using the right oil type, it's SAE 10W.
That is correct for the oil. Next thing to look at is those two relief valves. See if you can get a photo of each one so that any adjustment differences can be confirmed between the two.
It took A LOT of pressure to crack that. It might not be a bad idea to just replace or rebuild the relief valves if that option is available.
It'll take a couple of days for me to get those photos. I'll post them once I have them
Here are 2 pictures of the valves, pretty sure they were not tampered with.
The adjustment of the two valves appears to be much the same and certainly does not appear to have been messed with recently. In your original photo there is a small ding in the lower of the two plugs. That could potentially point to external factors such as a blow of some sort. The only suggestion at this point would be to maybe remove the two plugs and carefully pry the valve open using some sort of tool in the crack in order to be able see if the inner workings can give any clue as to why it happened. One question though. In the short time it operated prior to this failure did the parking brake work.?