Backhoe Jinma LW-6

[trelli]

Just another question. how do you know id the relief valve is working for the BH or the loader? When the BH moves to its maximum position there is a bit of noise coming from the PTO pump. Does that noise indicate that the relief valve is working?

However, when I use the loader, in maximum positions whether it be the bucket closing/ opening/ lifting etc the engine bogs down and shudders, like its really straining. That does not sound like a relief valve working??? When I feel the shuddering I release the lever immediately.

 

[Diamondpilot]

A relief valve should give a squeal. If is bogging the motor down its not set properly. On my 254 I set the loader relief at 2400 psi.

Chris

 

[Smalljobs]

I followed the teachings of another member, 3RRL, whose great technical postings you can find. I installed remotes, another relief valve, etc.

The take away is this: I installed a relief valve right next to the pump output and routed the relief port to sump. I also installed a pressure gage and set it to relieve around 2300 or 2400 as per the manual that came with the tractor. After that, I adjusted the relief valves, one at a time, on the loader and logsplitter to relieve at a lower pressure, maybe 100 psi less than the primary relief valve.

By doing this, the system was working to capacity but still protected while each accessory was also working with suitable pressure.

Hope this helps.

 

[California]

Could this BH have been delivered with a 'pto pump' that actually is designed to go on the front of the crankshaft, and turn at that faster speed?

The talk of a 3.5 : 1 step-up gearbox inside a pto pump doesn't sound right. Maybe they shipped you what they had, not what you need.

 

[Bob Rooks]

If the pump has a step-up gear case and fits onto the splined shaft, then the PTO must be operated in the 540 r/m range (giving roughly the equivalent of direct engine speed). If the pump has a tang drive and bolts directly to the differential housing then it drives at engine speed and can only be clutched out (no neutral). If you have a Prince or Prince-type of pump that slips over the splined PTO shaft, it must be operated in the 540 r/m range.

 

[20 20]

Trelli; It might help us to understand better if you have some pictures? Is it possible for you to take some pictures of your tractor the BH and the pump setup?

 

[trelli]

Not sure if it's the step up type but I think there's more to it than inappropriate RPM. I had it going at 2000rpm today and the boom had minimal grunt pulling itself up, infact I gave it a little assistance with my right hand and it moved up faster.....like it's JUST getting it up. At those RPMS everything else operates with a surprising violence, the downward stroke is like some hydraulic punch in the face and the side to side motion is ridiculously quick. I did manage to feather it somewhat and maintained a dubious measure of control over the wild beast.

I'll get some photos up after work. I've just ordered a pressure gauge to see what's going on with the whole system. Regarding the loader, I had a little look today and I think What I was look at was the relief valve, I took a long end nut off and there was an allen key bolt inside, I didn't change any settings as I'm unable to read the pressures just yet, but judging from the bogging engine when hydraulics are at its max, it'd probably not set properly as suggested by a member.

The manual says nothing about operating pressures. It's more of a safety manual.

I'm scouring the forums looking for 3RRl's and other's posts regarding the LW6 and, it seems like a very problematic BH. However I have no choice so I have to make it work.

 

[Smalljobs]

Trelli - The 3RRL posts were not specific to your backhoe but those posts and Rob (3RRL) taught me a lot about hydraulics. I don't have a BH. Good luck.

 

[20 20]

One of my problems on mine was the seal that was on the relief valve up inside. I missed it the 1st time I took it apart. The BH acted odd, power everywhere except to lift the main arm. Once I fixed the relief valve seal everything worked great.

 

[trelli]

Just got a few photos here, it's been raining so I had tarps over them. There are a few items on that I cannot identify or recognise.Any help is greatly appreciated. The manual does not identify these.

thanks