Hydraulic question

[wood butcher]

Patience grasshopper as the kung Fu man says,


You might look at the pdf below. It lists out a bolt (item 24) on the spin on filter cartridge. Although they don't clearly say it it might be the relief he is talking about. it sure look like a banjo bolt that could also be plugged. It should be easy to remove and inspect. The main relive valve valve on hyd system is downstream of the pump so it can not effect the pump flow/pressure when the discharge pipe is removed as what you have done. Again I'd personally make sure I inspect all inlet pipes/fittings right up to the pump before pump tear down.

JC,

Thanks for the PDF. I'll pull all of the banjo bolts I can find & see if I can find the dead rat!. I appreciate you helping me with this & thinking through it.

 

[JFS2295]

Please do not use your fingers to check hydraulic flow. People at worst have died from hydraulic fluid being injected into their blood system through the skin, or have had amputations at the least.

 

[wood butcher]

Please do not use your fingers to check hydraulic flow. People at worst have died from hydraulic fluid being injected into their blood system through the skin, or have had amputations at the least.

Okay. I read up on that a few months ago and saw it was a dangerous game. I wouldnt have plugged it with my thumb but the fluid wasnt coming out fast at all. Thanks for the tip!

 

[JC-jetro]

Okay. I read up on that a few months ago and saw it was a dangerous game. I wouldnt have plugged it with my thumb but the fluid wasnt coming out fast at all. Thanks for the tip!

The advice was good but there is a difference between a pin hole on a pipe/ hose under pressure where it shoots out few oz of hyd @ 1500-2000 psi and what you did. An open ended pump discharge will not cause pressure anywhere close to operating pressure. The design nature of Positive displacement pump and flow restriction in the form of relief valve/spring is cause of high pressure developed. Skin puncture was not a huge risk in your situation.

JC,

 

[wood butcher]

JC...did some more digging today and I found something I think is HUGE. I put the new filter on today and it did nothing except allow me to cross it off the list. I cut the WIX filter open & it wasnt clogged. Just FYI.

Got to thinking about what you said about the dead rat so I thought "OK I need to start crossing things off the list that could be wrong" so I went on a rat hunt. I drained the fluid again and started removing hydraulic lines. Every one I removed was clean. Took the banjo bolts off & all of them were clean. Now comes the interesting part. As I laid under the tractor I started looking at that diverter block and started to wonder exactly what it did and how that little shim (that's missing) would make such a difference in the pressure since it's about the thickness of a piece of paper. The guy at NH said it would increase the pressure about 800 pounds. Wow...that seems impossible. Anyway...so I took the big plug out of the bottom...the one that has the shims and the spring in it. As I laid there I looked at the length of the spring & jammed my finger in the hole all the way to my knuckle. I thought "something's missing." It looks to me like the poppet, housing and small plug (10, 15, 16) are missing. Now, I took this plug out when I drained all the fluid and left it out for several weeks. I looked all over the ground and I dont see the poppett or other parts anywhere. Is there any way, with 15 gallons of hydro fluid vs. the 6.8 it's supposed to have would make the hydraulic system work? It doesnt seem like it would but I know little about hydraulics.

I guess I'll go back to the NH dealer tomorrow and get those parts and see what happens.

 

[JC-jetro]

JC...did some more digging today and I found something I think is HUGE. I put the new filter on today and it did nothing except allow me to cross it off the list. I cut the WIX filter open & it wasnt clogged. Just FYI.

As I laid under the tractor I started looking at that diverter block and started to wonder exactly what it did and how that little shim (that's missing) would make such a difference in the pressure since it's about the thickness of a piece of paper. The guy at NH said it would increase the pressure about 800 pounds. Wow...that seems impossible. Anyway...so I took the big plug out of the bottom...the one that has the shims and the spring in it. As I laid there I looked at the length of the spring & jammed my finger in the hole all the way to my knuckle. I thought "something's missing." It looks to me like the poppet, housing and small plug (10, 15, 16) are missing. Now, I took this plug out when I drained all the fluid and left it out for several weeks. I looked all over the ground and I dont see the poppett or other parts anywhere. Is there any way, with 15 gallons of hydro fluid vs. the 6.8 it's supposed to have would make the hydraulic system work? It doesnt seem like it would but I know little about hydraulics.

I guess I'll go back to the NH dealer tomorrow and get those parts and see what happens.

I think that was the wrong plug you removed. I Suspect the spring , the poppet and the shim came off and potentially lost. As I said flow of the pump against a spring/valve developed the pressure. shimming it up or down will change spring stiffness hence more or less pressure. Right under the diffy where the draw bar is bolted to the bottom you see a hole. That is where the diffy drain plug is. The rat I'm talking about was there, as I opened the drain bolt there nothing came out until I stuck a piece of wire with a bend hook in there that I was able to pull the rat looking crap out. What do you mean with the statement below?

"with 15 gallons of hydro fluid vs. the 6.8 it's supposed to have would make the hydraulic system work?"

did you overfill your system? Do you know the whereabout of missing part. This is why I suggested to eliminate all potential problems on the suction side before getting to the pump. I believe you found your problems.

Jc,

 

[wood butcher]

I dont know the wherabouts of the parts that should be there ot the ones I probably lost but I know there's a NH dealer next door that can get new ones for me. As for the fluid, I got it with 15 gallons in it. The previous owner overfilled it. I suspect the original problem was the old filter was plugged up then when I drained everything I lost the poppet and the other parts. If NH has the parts Im going to try to get it going this weekend. I'll post what I find out. Thanks again for your help. It's about right that the problem was me, sadly. HA HA!!!

 

[JC-jetro]

I dont know the wherabouts of the parts that should be there ot the ones I probably lost but I know there's a NH dealer next door that can get new ones for me. As for the fluid, I got it with 15 gallons in it. The previous owner overfilled it. I suspect the original problem was the old filter was plugged up then when I drained everything I lost the poppet and the other parts. If NH has the parts Im going to try to get it going this weekend. I'll post what I find out. Thanks again for your help. It's about right that the problem was me, sadly. HA HA!!!

I might need to correct myself a bit. Your diverted block is on the discharge side of the pump, Right? can't see why overfilling it should effect the pump flow.

JC,

 

[wood butcher]

yes, the diverter valve is the first thing right after the pump on the discharge side.

 

[JC-jetro]

yes, the diverter valve is the first thing right after the pump on the discharge side.

Good, although it is hard to estimate free discharge flow out of the pump without some metering device(ie. 5 gallon bucket in this case), I'd expect a bit more flow or at least pressure being bulid up as soon as you did the "dutch boy" thing.You probably have a main pressure relief with the diverted valve in case of direct dead head to save the pump. Once you put he diverter back like it should I suspect you'll be good to go. If you're still in a pickle then pump is the last thing to look at.

Jc,