I have a D 39 PX 21 and the blade quit functioning and Forward and reverse quit functioning all at the same time the engine and everything still runs good. I checked the coupler between the pump. It’s still good. The charge pump is good and the gear pump, I have power down to all the solenoids. Is there anything in the pump that could cause everything to stop functioning? I took one of the lines off the blade and there is very little fluid coming out. Someone said it could be the hydra stats solenoid but I don’t know where that is located. Has anyone else ever had this issue? There was an Alan Dudley on here that had the same issue, but it never said what he did to fix it if anyone has any information, I would be very grateful, I tried reaching out to the Komatsu dealer and didn’t have any luck. I have two of the same machines the other one I rebuilt the final drive on it and I’ve never had any more trouble with it so I tried checking a few things back-and-forth, but I was just wondering , what could cause all the hydraulics to completely quit functioning
Does anyone know how I could check the pump? Where did you check for pressure at? Thanks for any info
There is a little bleeding plug #15 on this page , HYDRAULIC PUMP D39PX-21A S/N 1501-UP (Overseas Version) [d39px-0c] Komatsu 705-12-33110 Part catalog k-part.777parts.org And an oil sensor # 14 on this one HYDRAULIC PUMP (HARNESS BRACKET) D39PX-21A S/N 1501-UP (Overseas Version) [d39px-0c] Komatsu 11Y-06-21221 Part catalog k-part.777parts.org You are going to need a workshop manual for pressure readings , There are two pumps , for them both to fail it would appear supply needs to be checked first HYDRAULIC PUMP LINE (SUCTION) D39PX-21A S/N 1501-UP (Overseas Version) [d39px-0c] Komatsu 11Y-62-18110 Part catalog k-part.777parts.org
Sounds like a drive problem for your pumps. Possible coupler failure at the engine flywheel
My vote is for drive coupler.
That’s what I thought but I pulled the pump back and the drive coupler looks good, but I might pull it completely off and check and see if it has a keyway and I also change the pump on the front of the motor the supply hydraulic pump, but I haven’t changed the one that’s on the hydrostat pump Thanks for all the info. I really appreciate it. If anyone else has ever had this problem. Let me know what you did to fix it and I’ll try it on mine.
Does anyone know where the blade pump is located?
Does anybody on here know if the blade pump is built in with the hydrostat pump on that D 39?
I just had a similar issue with a much different machine and it was a loose ground.
Is your cooling fan spinning at the back of the machine?
This one’s like a 2006 or seven model the fans on the front on the engine. It’s got a manual fan. Everything on the engine works good. It’s just nothing on the hydraulics will function. I took a test light and check power all the way down to the solenoids on the hydrostat And I have power. Does anybody know if the hydra stats go down? Does the blade and everything quit working or will the blade still work and the dozer just won’t move?
What kind of equipment were you working on and what was it doing?
Not sure about a blade pump, there is a charge pump at the end of hydrostat pump stack. Charge pressure is important for shifting valves and spools for both the hydrostat and hydraulic work equipment systems. Have you checked the charge pressure? If it is low may cut open charge filter to look for sparklies. Sending you procedure to check charge pressure shortly.
Thanks I appreciate it. I’ll take all the help I can get.
I have a 39px -22. blade drops off. shut off restart and you may have it back. you may not. fan stops working as well. after a few key cycles you may get it back. or start it another time and it may work. so frustrating. I removed the pump inspection was done no issues re install and have 450 to 500psi at the post for valve spools. looking for advise. I have had komatsu here 2 times no luck no error codes
also when it works it works great for the 2mins. always have track drive though. Just loose blade