A reg Jcb 3xc 4wd hydraulic issue

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Muttsnutts
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A reg Jcb 3xc 4wd hydraulic issue

Post #1 by Muttsnutts » Fri Aug 23, 2013 1:13 pm

The issue i have is with the machine dying whilst operating all hydraulic functions some more than others though, and especially when holding legs up in the storing position and holding closed the four in one bucket. Things like opening the rear bucket do not seem to strain the engine as much as other functions, but still do have an effect. The engine will looseup to 500rpm if @ 1000rpm to start with, all fuel and air filters ok and engine power is great. As mentioned on a previous post I know there is a mrv valve on the left in line with the front lever spools, this is the one I have adjusted i have unscrewed in turns of a quarter up to one whole turn, but it seems to make no difference other than slow the left to right movement of the rear dipper arm. I do not know what the other valve is for behind the control levers ?. Does any one have the correct procedures for setting up hydraulics. I'm trying to source a gauge to measure the oil pressure at the two points on the machine which i assume is one by the side of the engine and the other in the rear valve block for the digging arm. The manual i have is not very detailed so if any one has had personal experience of this or is switched on in jcb repairs then your advise would be great. Failing all this any one know of a jcb mechanic in the south west area that would be willing to take a look, and a rough idea of what they might charge ? Obviously if I can adjust it that would save me a bit of time and money and would be easier for me. Thanks all in advance


jcb1968
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Re: A reg Jcb 3xc 4wd hydraulic issue

Post #2 by jcb1968 » Fri Aug 23, 2013 5:44 pm

Are you running this machine at just above idle?
You need to put the throttle at least midway, as even lowering and raising the legs will drag the engine down, especially when cold
1982 3CX4 sitemaster


philwheelton
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Re: A reg Jcb 3xc 4wd hydraulic issue

Post #3 by philwheelton » Fri Aug 23, 2013 10:00 pm

Is this a Perkins 4.236 engine M/C if so the metering valve in the fuel pumps had habit of going wrong and would rev ok but like you say pull right down when under load, I think the mrv should be set at 3000 psi on your M/C and it is in the front valve block.


Topic author
Muttsnutts
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Re: A reg Jcb 3xc 4wd hydraulic issue

Post #4 by Muttsnutts » Mon Aug 26, 2013 12:06 pm

philwheelton wrote:Is this a Perkins 4.236 engine M/C if so the metering valve in the fuel pumps had habit of going wrong and would rev ok but like you say pull right down when under load, I think the mrv should be set at 3000 psi on your M/C and it is in the front valve block.



Any idea on how to test the fuel pump or is it a case of taking it off and giving to a specialist. Do you have a idea of where to connect hydraulic guage to test the pressure the manual lists a few places and is not completely clear. The idle is a bugger to set, some times it will idle okay at 750rpm the the other it's up at 1000. I think I've found why the left to right dipper is slow, there is a dent in the left cylinder pipe at the bottom of the dipper arm.


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