Komatsu dozers and hystat issues

[John McDaniel]

Do komatsus seem to have more hystat issues versus either brands? iv got a d5g and it a great little machine? the machine I’m looking at is a 39px said it I’m assuming is swapping fluid from a final to a hystat or something like that. is this a common issue? can it be fixed relatively easily? machine is nice neat and straight as an arrow I think about 3-4k hrs tight machine also.




This is a copy and paste from the tec shop and the fellow with the machine







It looks like the final drive oil has transferred to the hydraulic system and has caused the servos to start sticking in the HST pump, the only repair for this that we recommend is a complete HST rebuild, this will run you somewhere in the neighborhood of $65K. I have included the hyd oil sample report and also the outstanding invoice for this machine, let me know if you have any questions.

 

[epirbalex]

Do komatsus seem to have more hystat issues versus either brands? iv got a d5g and it a great little machine? the machine I’m looking at is a 39px said it I’m assuming is swapping fluid from a final to a hystat or something like that. is this a common issue? can it be fixed relatively easily? machine is nice neat and straight as an arrow I think about 3-4k hrs tight machine also.




This is a copy and paste from the tec shop and the fellow with the machine







It looks like the final drive oil has transferred to the hydraulic system and has caused the servos to start sticking in the HST pump, the only repair for this that we recommend is a complete HST rebuild, this will run you somewhere in the neighborhood of $65K. I have included the hyd oil sample report and also the outstanding invoice for this machine, let me know if you have any questions.

At least it has not been mickyed up and you have been told whats wrong . Those hours are low and its probably worth fixing with a 65 thousand dollar question off the price and how the oil mixed . You may be able to use the same oil in its transmission as the final drives .

 

[John McDaniel]

At least it has not been mickyed up and you have been told whats wrong . Those hours are low and its probably worth fixing with a 65 thousand dollar question off the price and how the oil mixed . You may be able to use the same oil in its transmission as the final drives .

I have a buddy that his grenaded a pump kind of did the same thing except his would stop pulling on one side he paid got it fixed and hasn’t had a issue since

 

[CM1995]

Has the tractor been repaired yet or does it need $65K worth of work? The reason I ask is the "outstanding invoice attached" quote.

Depending on the age and hours if the tractor needs $65K worth of work it's probably a parts machine.

Quick search on MT shows several 39PX's with up to 4K hours from $75-120K. Personally I wouldn't put $65K into a used tractor unless the machine was purchased for scrap value.

https://www.machinerytrader.com/listings/search?Category=1025&Model=D39PX-21|D39PX-23|D39PX-24|D39PXI-24&Manufacturer=KOMATSU&Hours=3000*4000&Country=178&sort=2

If it's a $65K estimate to repair that's just the start of the bill. These types of repairs 9 times out of 10 go over the estimate.

 

[Welder Dave]

Any idea how long it leaked or how big the leak was? Of course they recommend a complete hystat overhaul but that may not be necessary. Perhaps a flush of the system may be enough to clean the hydrostat. When I thought the valve for my dump truck was sticking I looked to see if there were additives to free sticking valves. It may sound dumb to some but Seafoam Trans Tune is supposed to help remove varnish and free sticky valves in automatic transmissions and is also recommended for hydraulic systems. There are good reviews for it. There could be other products that a good hydraulic shop might have too. It might be worth trying to clean the system before spending $65K on a complete rebuild. It's different if there is metal or other debris in the system from a component failure. I'm not sure if there's a way to run a kidney loop on the hydrostat but polishing the fluid is worth a try in my opinion. If a kidney loop isn't possible could still drain and run the fluid through a filter cart several times. I'm thinking with only 3- 4000 hours it hasn't been leaking for very long. An oil sample might give an idea of how much the hydrostat was contaminated.

 

[Jmcdaniel]

I have a Komatsu D 39 PX Dash 21 and the blade won’t move up or down or nothing and it will not go forward or backwards. It’s like the hydraulics are dead and I already checked the pump coupler it is good but they were a couple guys on here that had the same issue And I was just wondering what they did to fix their is Alan Dudley still on here did you get yours fixed mines doing the same thing i’m getting Power to all the solenoids. Does anybody have a diagram of where the hydrostat solenoid is located? I took one of the lines off the blade and it has very little pressure. Someone said the pump could be stuck in de- stroke mode. what would cause that? has anyone else ever had this issue? Is there anyway all three pumps could fail at the same time?

 

[Welder Dave]

Probably should have started a new thread with a title more specific to your issues.

 

[Jmcdaniel]

Sorry not very good at this how do I start a new one?

 

[Welder Dave]

When you go on one of the forums there is a blue box at the top right for starting a new thread. Click on that and then put a title and then type what you need help with.