Backhoe jw03 no pressure

[ultraken08]

put new o-rings in prv cleaned and installed. put pump back togeather and installed. every thing works great except the boom coming back up. I have to wait a little bit then go up then wait etc.

haven't put pressure gauge on to adjust because I am waiting to figure out how to adapt it to the prv.

 

[Rich Waugh]

That slow boom, when everything else is okay, makes me think you might have a hose or a port partially blocked. The boom cylinder is the biggest one, so any decrease in volume of flow would affect it the most, I think.

 

[erj]

Here is a copy of the Email that I sent Kenny on Sat after I had sent the PDF files mentioned earlier in this threadl
Kenny,
My suggestions of what to do while waiting for the pump rebuild kit:
1.Did you check out the breathing method for the hydraulic tank?
2.I believe that you said there was still white fluid in the tank. I had that problem a couple of years ago. It took a couple of tank refills to get rid of it. I suggest that you remove and clean the filter that is in the tank.
[And since that gives you an access hole, I would run a magnet around in there to see if you get much metal shavings. You also could consider dumping in some kerosene to sort of swab it out. (suggestions only-probably not necessary(]
3.Disconnect the pressure hydraulic line between the pump and the PRV and blow it out. This should get rid of any pump seal particles that may have gotten in there.
4.Since you ran the pump with the bad seals after you rebuilt the PRV, I would consider rechecking that PRV valve to be sure no crud got in there.
Did you get the specs for the adapter for the pressure gauge? Do you have the other needed parts? That adapter and concept for it was developed by RonMar who hasn稚 been on this site for awhile. He lives in Port Angeles if I remember correctly. Attached is a copy of the instructions that he sent out a few years ago when he made up kits for several of us JW03 owners.

When these are done, the pump rebuilt and the pressure gauge installed then the pressure can be set on the PRV. I suspect that is the problem, but if that is set without these other things taken care of it could just crud up again.
RonJ

RonMar-welcome back, haven't seen your name here for awhile.

 

[RonMar]

Hey Ron, I sneek back in every now and then

UltraKen08, you might want to read thru the below linked thread. I learned quite a few things when I put in a return line filter on my BH. If your pump is making noise in operation, you will want to possibly look in to reconfiguring the return line to the tank, particularly that banjo fiting right at the tank. My pump has been quiet ever since I did this, as it should be, just like the main hydraulic pump on the tractor...

http://www.tractorbynet.com/forums/chinese-tractors/111225-jinma-hw03-backhoe-return-filter.html

 

[ultraken08]

Thanks Ron I'll look in to the filter for sure!

Got my pump rebuild kit today and installed it!

cleaned filter,blew out lines etc.

hooked pressure gauge up and let her roll!!

every thing worked, but I'm only getting 1500psi before the prv kicks in is that right? It's pretty much turned all the way in!

went out and used it seems to be working but fluid is coming out of my breather cap and vent on my dip stick any thoughts?

Thanks, Kenny

 

[RonMar]

Thanks Ron I'll look in to the filter for sure!
every thing worked, but I'm only getting 1500psi before the prv kicks in is that right? It's pretty much turned all the way in!

went out and used it seems to be working but fluid is coming out of my breather cap and vent on my dip stick any thoughts?

Thanks, Kenny

Kenny, if I recall correctly, it should be 16MPA, which works out to I believe around 2250PSI. You may still have some issue with the PRV not seating properly, or the pump is now only capable of outputting 1500 psi. The hot run may have caused some internal wear

How much fluid is comming out of the breather? If the tank is filled to the point that the bottom of the filler neck is suibmerged, and the dipstick/vent is not venting properly, when it gets warm, the air trapped on top of the fluid will push the fluid up the filler neck and out the vents in the cap. mine did this. Try removing the dipstick completely and see what happens... I ultimately did away with the dipstick and added a small inline automotive filter as an air filter, on a piece of rubber hose pushed down over the dipstick port(found it more usefull as a vent than a dipstick). I then sealed the ports in the filler cap. If I want to see how much fluid is in the tank, I unscrewed the filler cap and looked down the filler neck

The return line filter mod is a good thing. the importer I got my BH from said the only real problem they ever really had with these hoes was caused by crud in the oil interferring with the PRV. The main issue with the return line into the tank however is that it ends in a banjo bolt that has a small center bore. That small bore returns the fluid to the tank like a straight stream fire hose nozzle. It shoots right across the top of the tank as a high velocity jet and drags a lot of air into the oil as it enters violently. Shoot a straight stream garden hose nozzle into a bucket and you will see what I am talking about. if you open up that port so the fluid enters the tank more gently, it dosn't drag any air down into the fluid and the pump dosn't wind up ingesting a bunch of air. It is really bad for a hydro pump to pass tiny air bubbles. The pressure change makes them act just like sand, and it causes cavitation and pump wear... Depending on how that fitting is welded into the tank, that could also be why you are leaking oil out the top. If it is spraying against the filler tube, it may be splattering hard enough to find it's way up the filler neck...

 

[ultraken08]

Tomorrow I'll check the prv again and look into the venting again. I like the Idea of sealing that off and with a filter.
I did notice when I had the cap and filler strainer off the return line shoots the fluid right at the filter to the pump!! Something I will have to take care of.
The pump to my visual eye looked very good inside, but I'm finding it doesn't take much to make a head ache.

Thanks again, Kenny

 

[RonMar]

Tomorrow I'll check the prv again and look into the venting again. I like the Idea of sealing that off and with a filter.
I did notice when I had the cap and filler strainer off the return line shoots the fluid right at the filter to the pump!! Something I will have to take care of.
The pump to my visual eye looked very good inside, but I'm finding it doesn't take much to make a head ache.

Thanks again, Kenny

Oh, and 16 MPa converts to 2320 PSI... I looked back at an earlier post when I first fitted the gauge adapter and disassembled my PRV. I set mine for 2300 PSI. I need to put my gauge back on, as I havn't checked it for a while. Since I reconfigured my control cabinet and plumbing(tank is now mounted vertical between my knees), I think I have a safe place to permanently mount a gauge...