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Another lube pressure question...


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I've been searching the posts for an answer, but haven't found anything for sure. 

Got a 756 that I just replaced the hydraulic tellight in...now when hot, it pretty much stays lit. Checked the wiring, not grounded anywhere, so I put a gauge on it...

T/A lever ahead it has 0-1psi...

T/A lever back it has 3-5psi...

Halfway in between it has 10psi...

Would I be correct to assume the problem lies in the MCV and not the T/A? Everything works fine, steering, brakes, T/A all work fine... The history of the tractor is unknown, so I'm not sure how old the T/A even is.

With that low of lube pressure, I'm worried that it may cause a problem down the road, and I'd like to avoid that.

Travis

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Can you feel slippage in DD ? I'd say the mcv pump is weak

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53 minutes ago, ksfarmdude said:

Can you feel slippage in DD ? I'd say the mcv pump is weak

No. Like I said, everything works fine, steering, brakes, T/A....all works perfectly fine. I doubt its a weak pump.

Travis

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I looked in my manual and they mention leaking sump check. Did you check the regulated pressure? 

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31 minutes ago, FarmerFixEmUp said:

I looked in my manual and they mention leaking sump check. Did you check the regulated pressure? 

Not yet, and I've considered a missing check valve, but won't know until I remove the MCV.

Travis

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Test hydraulic operating pressure at 1800 -1900 psi, that will tell the pump & relief valve are working proper.

I-H relief valve $ 800.00 bucks, WOW  😲 😵

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14 hours ago, ksfarmdude said:

Can you feel slippage in DD ? I'd say the mcv pump is weak

I would lean that way too, line pressure is pretty much whatever oil is left over from the various consuming circuits unless there is a leak in one.  

Maybe it's just me, but I've disassembled bad mcv pumps (usually from losing and no able to reprime or weak steering at idle) , and compared to some I've seen, they dont really look bad.  For some reason it seems they're very fussy.  For probably 80% of the time not seeing oil pressures over 1000 psi, they still fail

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