Backhoe JW-03 Backhoe Problems

[little_fellow]

I used a 3/4 inch pipe threaded elbow which threaded directly into the tank and the filter head on the other end of it. From the filter head I attached a 1 in. rad hose which went on to connect to the control valve. I welded a pipe thread fitting onto the fitting that screws into the valve in order to attach the one inch rad hose to the valve. Those adapters on the ports , are they visible to the naked eye without taking anything apart? Sounds like you are saying the port adapters are screwed into the the valve and the o-ring face seal fittings screws into them or do I have to take the valve bank apart again? In the operation and maintenance manual I have a page that illustrates the backhoe hydraulic system assembly. This illustrates all the parts that could be seen without taking anything apart. I can see the o-ring face seal fittings on this page but I do not see the adapters. Am I missing something?

 

[RonMar]

Those adapters on the ports , are they visible to the naked eye without taking anything apart? Sounds like you are saying the port adapters are screwed into the the valve and the o-ring face seal fittings screws into them

Yes, that is exactly what I am saying. Disconnect the hose end ORFS fitting and then unscrew the adapter. If you do this to both the swing circuit and the Dipper circuit(the one that seems slow/labored?) and look thru those adapters I think you will find the center bores are different diameters. Swap both small ones to the swing circuit and both large ones to the dipper...

Well all filters will develop a little backpressure. Radiator/heater hose is more pliable/flexible and also not re-enforced as much as hydraulic hose, so may be distorting with the pressure. Another issue is a 1" line has a whole lot of internal surface area to interact with X PSI. Hydraulic hose is double wall with a steel mesh layer to resist swelling/expansion under pressure.

I did mine almost opposite to how you did yours. I connected the filter to the valve outlet/return port with the original high pressure outlet hose(ORFS end and adapter same as the rest of the ports on the valve) I cut the hose to length and swaged on a NPT to hose barb fitting which connects to the filter which is mounted to the side of the valve housing. From the filter back to the tank I run the low pressure 5/8 heater hose...

 

[little_fellow]

Yes sir Ron. You made my day. You solved the problem. Like you said, the adapters on the stick boom side had very small center bores while the swing side had quite larger center bores so as you know, after switching them over the backhoe seems to operate normally. Thank you very very much for all the help you've given me on this project. I really appreciate this.

 

[KyleLegg73]

2250 Should be fine. In the dim recesses of my brain I seem to recall the Chinese manuals spec(in Bar) is actually a little higher than that, but you need to protect for the lowest rated component in the system. Often that component is the pump... Hydraulically the only real issue I had with mine was the return line into the tank. This is a low pressure line. They used a high pressure line thru a banjo fitting with about a 10MM bore. This sends the fluid back into the tank at high velocity. What mine was doing was this straight stream was shooting back across and into the top of the fluid level and pulling air down into the fluid right in front of the pump suction line. Shoot a straight stream from a garden hose nozzle into a bucket of water and you will see what I am talking about. Hydraulic pumps don't like air in the oil and will complain by making excessive noise(wine/squeal). I replaced the return line with a large diameter hose and a large bore hose barb into the tank when I installed a filter and the pump immediately went quiet...

At any rate 2250 is plenty enough force to break parts of the structure. You have a welder right? Pay close attention to the top of the bucket opening. I may have gotten a Friday bucket, but they put a piece of angle iron across the top of the opening for re-enforcement. Mine was basically held in place by about 3" of weld total across the entire width of the bucket and ends. It was a hard spot to weld and hard to inspect. This led to deformation and separation of the bucket sides from the back/top at the top corners. The top of the bucket opening is probably one of the highest stress areas on the BH when you curl and rip. All the stress from the teeth get transferred up the sides of the bucket to the corners of the opening then inward to the pivot. If the top/corner support(that crossbar) isn't adequate or welded properly to hold things square, the bucket will fail. Once damaged it was quite a bit of work to reshape and put in a proper piece of steel(3/8 X 2 X opening width) strap properly welded... If you can weld and fab, I would recommend this modification before you really use it hard as cutting out what is there and welding in the new stronger strap would be real easy and take about an hour on an un-damaged bucket...

Howdy Ron. I'm new here & 1st reply. You talking about the bucket coming apart, I had that problem on the 1st job I did with the backhoe (lw-6a) on my Kubota L3400 I dug a little over a mile of ditch in caliche & about 3/4 of the way I peeled the bucket bottom back about halfway not a bad fix (I'm a certified structural welder) I used the hoe itself to push the bottom back in place a little bit at time as I welded it back up as I worked back towards the tooth edge until it was fixed properly & after I was done doing the job & I was loading the tractor on my trailer & got it loaded just before I shut her down the top link that mounts to the seat pedestal broke off down at the base, I used 1/2" steel plate welded to the base & then the upright & reinforced it there, then I guess it was about the 5th job I did I had 1 of thd control leveres snap the cone shaped actuator with the rounded top off & at this point I'm so glad I'm a welder since I had to weld & build it up to repair it again & finally the last job I was on my boom cylinder started pouring fluid out faster than you could pout more in so now I've got to take it off & clean & reseal it. I hope I've found & fixed all the weak links on this dang thing. BTW I'm seriously thinking of fabricating a narrower bucket for it & I took the thumb off as to it was in the way of trying to dig since when fully open it stuck straight down all I did was remove 1 of the thumb hoses & connected the other back to the side I took off.