Jcb 3cx 1982 no rear dipper power

[Muttsnutts]

As above no power when lifting bucket of dirt. Ok when empty. It seems Im having problems with my hydraulic pressure or relief valve. Any body know how to post pics ? i have a question over two mrv or arv valves, I don't know which is which ? i know the mrv to adjust the whole hydraulic system pressure but, what is the other one for ? Any help would be great.

I'm specifically having problems with just rear dipper arm not lifting buckets of dirt ok when empty.Any ideas on what may be the cause? Or where to start looking for the issue ? Thanks in advance.

[Stock]

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[Stock]

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[Stock]

By the way welcome.................

[Muz]

New members cannot post pics straight away to prevent offensive spammers.. you need a higher post count before it automatically lets you

However .. as you are not a bot .. I'll overide that for you now

[Muz]

The forum is now yours .. welcome BTW ..

[Wee Jim]

The forum is now yours .. welcome BTW ..

Is that you retiring from the forum game now then?

Welcome along!

[Muz]

Is that you retiring from the forum game now then?

Now what gave you that idea Jim lad ... eer.. whilst your on .. .. apart from a few shameless plugs that Ive .. ahem .. not seen ... your JD forum looks alright .. some good contributers on there with pics and all .. all good things take time fella .. just chill man

[Muttsnutts]

I sold my ford 550 to buy this 3cx the controls were a left righ, forward back movement but this 3cx is crossed like a x (cross) i have moved the left lever round slightly to match the ford. Could this be my problem ? I will return to original position in morn and re check before going any further, failing that., I have the manual but I can't seem to match diagrams or wording up to my machine. See my pic below I think I have identified the mrv valve correctly but not the other adjustment. the test method in the manual is unclear to me. I have adjusted both of these to try and stop the digger from stalling but now have this new problem. this only seems to have started this since i have touched the valves, although the valves are back in original position, (this may be just a coincidence though that is happened at same time). The rear dipper will push the machine up off the back wheels but not pick up weight in bucket which seems strange it only works with power one way. When trying to lift with the dipper with dirt in there is like a flowing noise that can be herd in the loader control spool block. I think it is louder when trying to pick up dirt with the dipper for example than any other function, but I will have to check that tomorrow. I'll post tomorrow as I'm off work and can have a good look. Thank you for the warm welcome.

[ianoz]

First up , Welcome to the forum .
Moving the lever around to the + pattern will not affect it .
Just check the linkage is not worn and not giving fullmovement to the spool valve .
3CX model has been going for over 30 years , so make sure the manual is to suit the machine you have .
First suggestion would be a good clean down ,to be able to actually see what you are trying to look at . And then if you need to pull something apart , you won't get crap dropping down in the workings

[Muttsnutts]

Sorted well kind of. Lol

I have topped up with 32 hyd oil about 25ltr. It was very low. I've managed to get the boom lifting working correctly again now just tweaked the mrv pressure up a little, it must just effect the main boom slightly more that the others, may just be the size of the ram I haven't used a gauge but I will fine tune at weekend when I get get a gauge. Back with the stalling problem again now eg when holding 4 in one against ram stops ect...May just be the the way the machine is. I'm not going to touch any others settings. Unless any one has any ideas of what may be causing it. Like the oil quality or something stupid.

[Muz]

Sorted well kind of. Lol

I have topped up with 32 hyd oil about 25ltr. It was very low. I've managed to get the boom lifting working correctly again now just tweaked the mrv pressure up a little, it must just effect the main boom slightly more that the others, may just be the size of the ram I haven't used a gauge but I will fine tune at weekend when I get get a gauge. Back with the stalling problem again now eg when holding 4 in one against ram stops ect...May just be the the way the machine is. I'm not going to touch any others settings. Unless any one has any ideas of what may be causing it. Like the oil quality or something stupid.

You might have a mixture of problems,... could be you have over egged the main relief and have an engine thats down in power a bit, and thats why its stalling.

Or / also.. if its a variable displacement pump, some of them have a valve on the pump that gets the swash plate to return to the 'no load' position, i.e. flat, at shut down, so the hydraulics cannot be loaded during machine start procedure, so as not to damage the starter. If this valve/spring combo fails, the pump gets stuck on full delivery all the time, so when you pull on a service, you get all the pumps flow causing the engine to be excessively loaded. I have a sneaking suspicion that yours will be gear pumps though, can you get a pic ?

[Muttsnutts]

You might have a mixture of problems,... could be you have over egged the main relief and have an engine thats down in power a bit, and thats why its stalling.

Or / also.. if its a variable displacement pump, some of them have a valve on the pump that gets the swash plate to return to the 'no load' position, i.e. flat, at shut down, so the hydraulics cannot be loaded during machine start procedure, so as not to damage the starter. If this valve/spring combo fails, the pump gets stuck on full delivery all the time, so when you pull on a service, you get all the pumps flow causing the engine to be excessively loaded. I have a sneaking suspicion that yours will be gear pumps though, can you get a pic ?

According to the manual it is a twin pump as it has a extending dipper, yea I can do a pic straight through the front grill ? I'll take a couple and see what is the best one. I'll have to put a gauge on at the weekend to see what pressure it's releasing at but I'm sure it can't be this. At 1500rpm it drags the engine down around 400rpm when digging ect but has plenty of power.

[Muttsnutts]

According to the manual it is a twin pump as it has a extending dipper, yea I can do a pic straight through the front grill ? I'll take a couple and see what is the best one. I'll have to put a gauge on at the weekend to see what pressure it's releasing at but I'm sure it can't be this. At 1500rpm it drags the engine down around 400rpm when digging ect but has plenty of power.

Not a great pic but can't get to the tools to remove front grill, might me able to see the pump. Let me know if its any good. image.jpg

[Muz]

I think its gear but hard to say. I think I can remember old 3c's labouring a bit at the best of times, are your filters all good in the hydraulics and on the fuel side of things ?