B8200 3PH pressure check

Codyrapoza

New member

Equipment
B8200 4wd hst
Apr 25, 2020
26
1
1
Ogden, utah
Hello all! I am getting some noises from my hst 4wd that seem random but sounds like relief valve or air. Hydro fluid has no bubbles and has been changed along w filter and screen cleaned with new o rings. Not sure if it did this before because I am a new owner. I checked the diverter on the block and it is in the Ccw position against the new roll pin I installed because I have no loader atm. 3 ph seams to function and seems strong I am wondering where to tap into to check the pressure. The wsm has a pic but it’s worthless. I’m thinking one of the two internal wrench bolts on top but not sure if it’s the big one or the little one. Next I will put a gauge on the block pressure port to loader and deadhead the gauge there to read relief pressure. Thanks, any input is welcome.


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Dave_eng

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M7040, Nuffield 465
Oct 6, 2012
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Williamstown Ontario Canada
When you use the term dead head, it has serious connotations. Often it destroys the pump as the pump can increase its pressure until it self destructs..

Wherever you connect a gauge you need to ensure a relief valve is in the circuit between the pump and the gauge.

If you connect before the loader valve you may have bypassed a relief valve. Certainly, if there is one in the loader valve, you have bypassed it.

To check pressure at the loader, connect to one of loader valve ports feeding a cylinder. In that way the loader's relief valve can protect the pump.

If the WSM illustrations or photos of the 3 pt test point are not clear, then I suggest you post photos of where you plan to connect a gauge and someone will clarify the location.

Dave
 

Codyrapoza

New member

Equipment
B8200 4wd hst
Apr 25, 2020
26
1
1
Ogden, utah

I’m thinking the gauge is supposed to go into one of the two internal wrenching bolt ports. There is a small one and a bigger one.


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Dave_eng

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M7040, Nuffield 465
Oct 6, 2012
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Williamstown Ontario Canada
I have attached instructions from a B8200 WSM I have re checking hydraulic pressures at the hydraulic block.

All illustrations re checking pressures other places are very poor quality.
I do not think the hex plugs in your photo are the ones mentioned.

Dave
 

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Codyrapoza

New member

Equipment
B8200 4wd hst
Apr 25, 2020
26
1
1
Ogden, utah
There are 2 different checks. One that you provided photos of us what I was trying to describe. The other is for the 3 point system. It is also in the wsm.


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Dave_eng

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M7040, Nuffield 465
Oct 6, 2012
5,108
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Williamstown Ontario Canada
I have three different B8200 WSM and had seen the page you provided.

None of the 3 WSM's has illustrations clear enough to determine where to connect a gauge.

If you do the hydraulic block pressure test and cannot get a pressure to meet spec then there is no point in worrying about the 3 pt assembly.

Dave
 

Codyrapoza

New member

Equipment
B8200 4wd hst
Apr 25, 2020
26
1
1
Ogden, utah
I think there is a relief valve in the 3PH valve body that is actuating sometimes randomly so I think I have too high pressure back there that’s why I wanted to check it with the gauge.


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Dave_eng

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M7040, Nuffield 465
Oct 6, 2012
5,108
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Williamstown Ontario Canada
I think there is a relief valve in the 3PH valve body that is actuating sometimes randomly so I think I have too high pressure back there that’s why I wanted to check it with the gauge.


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The pressure in the complete hydraulic system cannot get any higher than the first relief valve in the system which is the one in the hydraulic block. That is why checking pressures at that point should be your first step

If weird things are happening with the 3 pt movement then suspect the adjustment of the feedback rod.

The 3 pt relief valve will only activate if you reach the top of the stroke or are lifting too much weight.

The instructions for checking the block relief valve setting have you slowly cutting off the flow to the 3 pt hitch.

I think ( but am not completely certain) that the gauge connected to the block can also see the pressure going to the 3 pt hitch with the flow control wide open and you activate the 3 pt lever

Dave
 

Codyrapoza

New member

Equipment
B8200 4wd hst
Apr 25, 2020
26
1
1
Ogden, utah
This problem also seams to be tied to the hst. As in sometimes it’s brought on by pressing the forward pedal with 3PH up. It is pretty random and pretty annoying. I adjusted the feedback rod per wsm and no change.
 

Dave_eng

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Equipment
M7040, Nuffield 465
Oct 6, 2012
5,108
926
113
Williamstown Ontario Canada
The two hydraulic systems, HST and then the 3 pt , power steering if present and a loader have little to do with each other. Think of the HST unit as a self contained package which has some small leaks in its part of the case. A small amount of fluid is provided by the main pump to the HST unit to make up for the internal leaks but typically at a much lower pressure than the main pump outputs.

dave
 
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