I'm looking for help diagnosing the hydraulic pump on our d4h. It stopped working pretty abruptly, it was a little low on oil, topped it off. All three functions on blade are very slow as well as the ripper. It will kind of lift the dozer a little but doesn't seem to bleed off. It will lift the ripper very slowly and it will stay up for several days. I can't hear the motor labor but it's moving such a small amount of oil I don't think it would. Any help or ideas?
Collapsed or leaking suction hose maybe.
As per usual please start with a Serial Number. It makes looking for information a lot easier. Do you have access to pressure gauges to test the hydraulic system.? It would probably need a gauge capable of measuring up to about 3000 psi but need to confirm that based on Serial Number. . If you are prepared to sacrifice the hydraulic filter remove it and cut it open to look for metal particles in it. See the video HERE showing the method. I know this is an engine oil filter but the basic technique is the same.
compensator valve is probably sticking its the little valve mounted on the pump
Serial...8PJ00702. 8E8668. ENGINE 3304 I can cut open the filter.. can I use another machine to help lift the blade and the ripper off the ground to bring it to the shop? Seems the functions are slower every time I start it. I can't find a picture of the location of the pump, is the compensator valve something that can be fixed or does it need to be replaced. I don't see any leaks under the machine. I don't have a pressure gauge for that much pressure but will get one to help diagnose things. The tilt cylinder is the easiest access, can I put it in line there. Thanks a bunch...Todd
Thinking about it that was a dumb question about the pressure gauge at the tilt cyl. If there us pressure there it would move the cyl...where on the pump would one check . Thanks again
hy Your machine may be fitted with a variable displacement pump… which turns the circuit into a litle complicated diagram… nevertheless this systems very hardly have faults, and when they do is cause of contamination, metal plastics, rubber…. Parts that once belonged to the system. Usually one starts by looking for contaminants, air leaks , and small operation faults. Pretty sure u will find the culprit once u examine the filters and strainer, if they turn out nothing, check for air leaks at pump intake. I really doubt a control issue alone, but that is my 50 cent bet.
Thank you
This is the compensator (circled) mounted on the back of the pump. The pump is located under the cab floorplate. Attached the parts breakdown of the pump and the removal instructions, not necessarily to remove the pump but to give you an idea of what everything looks like under there. It also contains the instructions on how to disassemble & reassemble the compensator valve.
You need to drop the belly pan to get to it better
That’s the 2nd step in the procedure to remove the pump. Can you get the compensator off the pump without removing it.?
I could not but I'm fat and old
Do you have a different link to those pdfs I can’t open them. I’m having the same issue, sorta the same issue I should say but I’m wanna try to tear this guy apart to see what the deal is.
A lot of people have trouble trying to open them in a phone, I have no idea why. You’ll need a laptop or desktop PC. Download the pdfs to the desktop and open them from there.
Got mine torn down but it really doesn’t appear off in any visual way. Any key things I should be looking for?
Little back story on the one I’m dealing with this is being relayed to me thru the current owner. It worked fine when he got it. It slowly started to loose hydro fluid with no obvious leaks. I checked no cracked or leaking hoses. It tracks and moves around fine but has absolutely zero lift control for the blade and after a minute of running it around with the blade chained up … don’t ask I got there and it was like that lol. Anyways after a few min of running it around I let the blade fall to the ground with the help of another machine and in testing for angle and tilt functions it slowly lost pressure along with all other functions. I checked fluid and filter and I have never seen this much water contamination in a system like this before. It was pure white and the filter (after being cut open) has a small but consistent amount of metal in it. I have purged the whole system and flushed with fresh fluid but to avail. Also the owner supposedly had the valve pack rebuilt by two separate shops prior to me arriving. Yet I open it to find one of the (plug) ball bearings PN:5H-1472, in the tilt valve to appear as if it was literally punched in with a noticeable punch mark in the top of it and it was stuck in the seat unlike all the other valves where the ball would come out with a magnet. Anyways I’m still trying to see what else it could before I tell him he need a $3500 valve. The material in the filter led me to the compensator. Sorry if there are spelling errors. Currently driving I know bad on me lol.
I did with no issues.
Where is that coming from I wonder.? Pump would be my guess.
You need to remove hyd. tank and pull the side off of it and clean it out you will find a layer of metal in the bottom
Ya I flushed everything out I’m not worried about that anymore but I’m just worried about where it’s coming from because I’ve torn apart everything but the pump it self
I’m still just wondering why it has no lift control but had tilt and angle. If you look at the diagram on how it works it makes no sense. I’ve thought that I had the problem isolated 3 times now but I keep coming up with nothing. Orr or… lol I find more issues which is usually the case with this machine. It only has 2000 hours but it’s been so neglected.
Flushing is a bit different to taking the side panel off the tank and cleaning inside IMO. Maybe I'm just misunderstanding what you actually did. Either way you'll probably end up going back and cleaning it again once you find out where the particles are coming from. You mentioned the internal issues in the control valve. Possibly the culprit, especially if so many hands have been there before you and someone didn't reassemble it correctly.? You do have a copy of the hydraulic schematic I take it.?
I’ll take whatever you have if you’re offering. Also where do you source all your schematics because it was like pulling teeth to get what I got. Cats really no help and most small shops give you a hard time if you’re just calling for prints or manuals.
Here’s the pic of plug that’s literally punched into the seat.
You never mentioned the Serial Number. I can probably rustle up a schematic plus some documentation on how the system operates
Check your messages.
Yea I flushed everything too but took tank off and found a thick layer of metal in the bottom
It takes less pressure to do those function you are operating on stand by pressure put the blade in a bind and see if it stops. Since you had the valve rebuilt twice I dought if your resolvers are bad
I took the compensator valve off 3 or 4 times before it worked for any length of time it just takes a spec to mess it up
Hi I have had new seals and my pump serviced after it stopped working , the mechanic that got it running was unable to set the compensatory valve, stating it was screwed right in but he doesn't believe that is the correct setting. Do you by any chance know the settings or how far the screws are to be screwed in and out of the valve. It is the same set up as the PDF you posted of the pump and valve for Cat D4H serial number 3ac00622. Any help would be greatly appreciated
Tell me your Serial Number and I will be able to answer that question. To set the compensator you are probably going to require at least a pressure gauge.
Sorry I misunderstood your question. The Part Number of the Pump Group pump on 3AC00622 is different to the pump on 8PJ00702 which was the subject of the initial query. The basic pump is the same but it uses a different Part Number of compensator valve.. If you need to do it then the procedure to R&I the pump will be the same as was posted earlier. Attached the Test&Adjust procedure for the Implement System. A word of caution - you cannot go directly to adjusting the compensator. All the necessary tests need to be done in order, starting on Page 9 of the attachment and working downwards. Necessary tests/adjustments 1. LP standby. 2. HP stall. 3. Margin pressure. Only THEN do you get to adjusting the compensator.
Hi Nige thankyou so much for attaching the test and adjust procedure we have only just got the pump back and will installed and set it up tomorrow. Thankyou you again and I will let you know how we go. I have only just come back onto the forum and noticed you had attached them.
Hi, I have a problem with my Cat D4H. No lift control, but it has tilt and angle. There was water and dirt in the tank. I changed the oil and filter but nothing happened.
check the resolvers in control valve
And if you want more detailed information you will need to post a machine Serial Number.
How do I check that?
Do you have any Parts or Service Manuals for the tractor.?
No
See the attachments. You are looking for the main implement control valve, 9T-9184. In that valve there are 4 sections. You should inspect #5, the one marked "Lift" on the main illustration. See the detailed breakdown in 9T-6697. Check for three things: - 1. Free movement of the two balls that are marked in red. 2. Any damage to the O-Rings and/or backup rings reference numbers 22, 28, 29, 30, 31, and 32. 3. No dirt or debris in the small passages in the valve sections. By your description of what was in the tank I think it is highly likely you will find some level of contamination in the control valve. If you find damaged/missing O-Rings in the Lift section of the control valve then you should also inspect the other three sections because they are likely to be in a similar condtion. If I recall correctly the same Part Numbers of O-Rings and backup rings are used in all four valve sections.
Do I need to remove the valves?
I don’t know what the access is like on your machine. One of the valves that you have to remove is hidden on the bottom side of the valve, the other is on the left side of the valve as seen in the photo. If you cannot access both of those areas with the valve installed on the machine then the only solution would be to remove it before starting to disassemble.