The D8K we have keeps snapping the shaft in the hydro pump, we lose the tilt on the blade and the ripper. Five in the last couple years, the last one has less than 200hrs on it. We have replaced everything other than the cat it self, any thoughts
Hi rovation With you hydraulic problem when you say it keeps snapping the shaft is that the main shaft to the hydraulic pump itself because if that was the case you would loose all hydraulics? The pump I am thinking of is a 2 section pump, the front section (larger section) is your blade lift, and rear section is for tilt and ripper control, I've done a fair bit with d7,8,9 flat track crawlers so if u get a chance flick us a bit of info on what you have already done and I'll try and help! Cheers
That's a piggy back pump arrangement with splined coupling shaft for the tilt/ripper section. Seems there would be an alignment problem to continuously break shafts????
OK, so the pump is snapping the shaft in betwen the two sections. Exactly what parts are you replacing when this failure occurs and are you using genuine OEM Cat parts, Cat Classic Parts, or "will fit"...? Also what does the rear section of the pump that supplies the tilt & ripper look like when the failure occurs..? Are there any signs that it is seizing up and that's what is breaking the shaft..?
We have been replacing the pump with cat pumps. It breaks the shaft right where the shaft reduces to about 1/2 inch, you can see where the spline starts to twist and then it breaks clean also the o rings blow, not sure if this happens before or after the shaft breaks
Relief valve!
Good point. To the OP - Have you done any pressure tests at all..?
I too would check the relief valve. Had similar issue many years ago, but on a different machine. Root cause was from 1st pump failure, it sent debris up the line into relief valve, and was just about dead heading the system.
Sounds like you have a blockage in the output of the circuit
Near dead heading the pump would probably do it (max relief setting is 2500 psi). Just would have thought that would have been checked on the first or second failure, not five or six pumps later. Was looking for something more complex.
Sometimes the simple things in system diagnostics just fall through the cracks and nobody realises until the question gets asked..............