# Hydraulic pressure relief valve position with loader



## Raven6 (Mar 7, 2020)

Had a fire. In replacing items, have now a YM2310D. Realize the tractor is pretty old, 
the hours were not bad, and this one has both loader & added power steering. My issue is the 
power steering has killed the engine at just above idle. This issue, as I am "sort" of knowledgeable,
is capable of being catastrophic. So, being so new to me, I parked it until I could ascertain and 
rectify the issue. Where would I adjust the pressure relief valve? - Reviewed the three point pressure 
knob, in a diagram, while since the P.S. is an addition, is there another to adjuste? Shaft shear is 
concerning. Thanking in advance for thoughts.


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## sixbales (May 18, 2011)

Howdy Raven6,

Does your power steering have its own pump? Or does it tap into your tractor's hydraulic system? If it has its own pump, the relief valve should be in the pump.


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## Raven6 (Mar 7, 2020)

After inspection, all hydraulic operations "appear" to originate from a pump mounted right side, mid block facing forward. the two main lines are 3/8, and the loader handle has a 4 gang and an inlet and outlet. It is dark in the container ( temp. Storage ) and cramped. Since this is probably an add on, while using the main pump and frame tank, there must be an accessory inlet & outlet possibly beneath the center section? connected to the steering box? 
My Yanmar service manual does not note any PS information. Short presumption, all on one convoluted system.


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## Raven6 (Mar 7, 2020)

Missed one more thing, and that is the action occurs at either end of the cylinder stroke "ie" turning left or right.


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## FredM (Nov 18, 2015)

You are loading up the hydraulic pump when you do a full turn either left or right with the steering ram extending fully either way??, if this is the case, then one doesn't extend the ram fully, you can do the same thing with the loader controls, crowd the bucket and hold the lever in that position until the engine stalls, it is not meant to be done, you have to feel the limits of the steering and ram strokes.


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## winston (Aug 19, 2008)

Loaders have a relief valve that should relieve before killing the engine and although not positive I believe the actuator on the power steering should have a relief valve also. I would go on to say you should try to avoid going to the end of the actuator stroke and holding it there. Much like older cars might make the belt slip when doing that.


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## FredM (Nov 18, 2015)

It does happen winston, I have done it on 950 and 966 cat loaders unintentionally, same with the articulated steering on the machines, at idle this will stall the engine.


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## winston (Aug 19, 2008)

Not meaning to say it can't happen, just don't think relief valve should be set high enough to kill engine if engine is at proper idle speed.


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## Raven6 (Mar 7, 2020)

Thank alll of you for your thoughts, as this unit is new to me. I am aware of hydraulic theory to a point, and grasp the position of bump stops, and so on. The key here is the kill point is less than the end of the throw of the cylinder by some margin. If the turn radius is for example 45 degrees left or right, the buildup begins at 30 degrees, obvious at 38 kill at 40 - not 45. Could the cylinder they mounted be too short? My thought was that they did not set relief, so it is too high too soon. So I am back to where is the pressure relief unit, would it be in the four way valve if the steering is after the loader, flow wise? Since this tractor was assembled prior to my purchase, procedure would appear to be one of the possible issues. As well, could the steering arm the cylinder is attached to for the throw, too long" as these machines appear to be both manual & power steering. A short arm, would shorten the cylinder travel, both ways. My apologies for insufficient detail.


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## FredM (Nov 18, 2015)

Raven6 you cannot shorten the main drag link, you would end up with a tight circle one way and a larger circle the other,-- can you disconnect the ram shaft end off of the drag link and then do a full right and left turn just to see if the ram shaft does travel enough both ways?, there is a possibility that the ram is too short.

What make of tractor is it?.


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## Raven6 (Mar 7, 2020)

YM2310D Yanmar - From what I can find as literature ( slim ) these were manual steering as well. When I bought this unit, being neophitic, I was quite sensitive, as a learning issue. As I used it more, I had the engine stop, and understood the symptoms, but not having the schematics etc. am unable to extrapolate the actual issue. As a side issue, the bolts holding the cylinder mount to the block worked loose ( wrong size ), so cleaned bore tapped and replaced with correct dimension bolts, so I do not have the assurance the cylinder is correct throw length. Working loose was a hint of the other issue as well. Regards.


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## FredM (Nov 18, 2015)

Here is a manual that covers your tractor, with regards the steering, only shows manual steering, shows the hydraulics a bit smudgy, but you should be able to work it out.

Over time, the tension of the pressure relief valve spring should ease off and the pressure should slacken a bit, I would be careful with adjusting the valves without a pressure gauge.

Usually power steering pressure is not full hydraulic pressure, but it is regulated by a flow divider which should be in the pressure line after the pump and the steering feed should come off of this divider.


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## winston (Aug 19, 2008)

May not be of help but here is a add on power steering unit manual by Yanmar for smaller units. I suspect yours is probably very similar. I believe your relief valve would be in the actuator. Under specifications it states relief valve factory set at 1200# + or - 100#. Might or might not be right for your unit.


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## Raven6 (Mar 7, 2020)

To Winston & Fred - Thank you for the knowledge you are giving. Winston, thanks for the Manuals, and the principles of the PS should well be the same. The fact they note a factory relief setting, etc. should assist. While not ideal, at least I, unlike San Diego and Long Beach, have my container. Been raining here in Oregon for 9 days straight. Plenty of time to figure this out. Kindest to all, and have a warm and comforting Christmas season.


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