# Any backhoe maintenance techs here?



## Cmp1 (Mar 1, 2016)

Just wondering,,,, have a buddy who's having a problem with his backhoe, and I'm gonna need to borrow it,,,, thanks


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## BriarPatch99 (Mar 1, 2016)

What is happening with it ... I'm not a tech ... but have worked on many different kinds of equipment ....


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## Cmp1 (Mar 1, 2016)

BriarPatch99 said:


> What is happening with it ... I'm not a tech ... but have worked on many different kinds of equipment ....



Can I Pm you? Long story,,,,


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## Cmp1 (Mar 1, 2016)

Allright guys here is what we have, my buddy has a JD 410c 4wd, extend a hoe, his friend burned up his hydraulic pump, never low on fluid, was on high pressure, over heated the pump, by the time the idiot light came on it was too late, no gauges, and the guy running it didn't know what he was doing, anyway got a 3500.00 pump, install ed it, and now the servo actuated relief valve isn't working, the servo does, but the valve doesn't, so he's having a hard time starting it because of the hydraulic pressure preload, supposedly you can turn the steering wheel to relieve the pressure but that isn't working, he's checked all screens, filter, new JD fluid, and no leaks,,,, How can he put a relief valve on the pump? and what would keep it on high pressure instead of going to low pressure when not using any of the implements, ie bucket or hoe? He's afraid to drive it over to my house, about 7mi, for fear of ruining his new pump, he has no trailer,,,, short of putting a temp and pressure gauge inline, checked that out, really expensive, trust me, but he might end up doing that, but he shouldn't have to, the tractor didn't come with them so why would he have to go that route,,,, does anyone have any experience with this or any ideas,,,, this pump controls everything, transmission, steering, implements, with its own cooler,,,, thanks


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## tree cutter 08 (Mar 1, 2016)

My guess would be to replace the relief valve.


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## hancock husler (Mar 1, 2016)

Did he bleed the system of air


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## BriarPatch99 (Mar 1, 2016)

Are you sure that what you are looking at is not the pump Destroke Solenoid instead of a pressure relief valve ?


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## BriarPatch99 (Mar 1, 2016)

Unless I am wrong(I could very well be) ... Pressure is adjusted by hand using a 3/4" wrench to unlock the lock nut and screwing an Allen head bolt in or out ... 

You would need a in line gauge to adjust it properly ... You would need to check a manual for the correct pressure.... I believe it to be  around 1800 psi operating(I could be wrong) ...


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## Cmp1 (Mar 2, 2016)

BriarPatch99 said:


> Are you sure that what you are looking at is not the pump Destroke Solenoid instead of a pressure relief valve ?



Yep it is the destroke solenoid, it is working, but the actual valve isn't, but that wouldn't keep it on high pressure all the time would it, that is only to back off the pressure on starting,,,, he did adjust the pressure with the screw on the pump in the front of the pump, he has the manual and adjusted it to specs,,,, the problem in my mind is isn't there an internal relief in the pump? Not for starting, but to back off the pressure if it is staying on high press, he was thinking proportioning valve, he says the manual isn't clear about it, I guess I can't get my head around how you can fry a pump, by being on high pressure for extended periods of time, what if your using the hoe for extended periods of time,? The problem also is that he's paying on the pump and can't use the hoe, for fear of burning up the pump, can he put a relief in line from the pump? He's trying to save money, he doesn't use the hoe for a living, just trying to make some money off it part time,,,, he's talked to JD and AIS, no help, wants him to bring it in or come to his house,,,, big bucks, any thoughts you can suggest is greatly appreciated,,,,btw, he did bleed the system also,,,,


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## BriarPatch99 (Mar 2, 2016)

If the destroke valve is not working ...it would cause the pump to output at full volume all the time ...   that is the reason for the Destroke to reduce pressure on startup ...   that is why the engine will not crank ... it is locked by full pressure ... (then again I could be totally wrong)   

Pull up the parts list on JD parts and you can see how it goes together ... there is also a rebuild kit for the Destroke valve  ... 

I would look hard at that valve(and possible rebuild) before I burned another pump up ...   

There is (or may be) another pressure relief valve under the belly near the two filters ... it is adjusted with the Alan bolt also ...  that controls working pressure also...


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## Cmp1 (Mar 2, 2016)

BriarPatch99 said:


> If the destroke valve is not working ...it would cause the pump to output at full volume all the time ...   that is the reason for the Destroke to reduce pressure on startup ...   that is why the engine will not crank ... it is locked by full pressure ... (then again I could be totally wrong)
> 
> Pull up the parts list on JD parts and you can see how it goes together ... there is also a rebuild kit for the Destroke valve  ...
> 
> ...




Sir, are you saying that after the pressure is relieved for start up, that valve keeps the pump from full output all the time? I know it breaks pressure for start up but after that it works as pressure regulator?


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## BriarPatch99 (Mar 2, 2016)

I don't have access to shop manual for that tractor    ... but I don't think the destroke valve acts as a pressure regulator  ...  as far as I remember there are two pressure relief valves... not really regulators ... but to relieve pressure to bypass at a set pressure ...  

There is the one pressure relief valve on the pump and another under the belly ...   best I remember they both are adjusted by screwing the Allen bolt in or out ... 

Sorry it has been a long time since I had hands on one...


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## BriarPatch99 (Mar 2, 2016)

There is a fine wire mesh filter on the bottom of the very front section of the pump housing ...  I believe it is a 1-1/4" hex nut/plug ... this may need to be cleaned ... it is called the pump stroke control valve filter element... 

Not sure if this section comes with the new pump that he bought ... if it is new disregard that idea...


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## Cmp1 (Mar 2, 2016)

BriarPatch99 said:


> I don't have access to shop manual for that tractor    ... but I don't think the destroke valve acts as a pressure regulator  ...  as far as I remember there are two pressure relief valves... not really regulators ... but to relieve pressure to bypass at a set pressure ...
> 
> There is the one pressure relief valve on the pump and another under the belly ...   best I remember they both are adjusted by screwing the Allen bolt in or out ...
> 
> Sorry it has been a long time since I had hands on one...



No need to be sorry buddy, I appreciate any ideas and help you can offer, I found the rebuild kit for the destroke valve, the solenoid is operational, but the seals could be bad, the rebuild kit is less than 50.00,,,, but it still is under pressure, hard to start, he didn't know about the relief valve under the belly, he's gonna check that valve,,,, he wanted me to ask you about the proportioning valve, I understand how it works and I found a partial flow chart, but I read something about that valve supplying the pump with hydraulic fluid, I know it gives priority to the steering, do you have a good flow circuit chart? I also read this hydraulic system is one of the most complicated made, I've searched Google, I told him he should have just gotten a Case, I ran a old 580d, never had a problem except for a broken hydraulic hose,,,,


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## BriarPatch99 (Mar 2, 2016)

Again I may be wrong but I believe the proportioning valve gives priority to the backhoe section over steering ...   you may lose steering if you try to steer while operating the hoe ... 

I don't have a chart ... I'll see if I can find one ... 

Make sure he checks that screen in the pump stroke control ...

JD is a fine machine when it is running well ... the Case ain't as pretty and slick as the JD .... but is just about bullet proof ! 

I know he has tried turning the steering wheel to relieve pressure ... but has he tried to operate the hoe boom arm at the same time as cranking ... make sure the area is clear and nothing is in the way ... it may jump ...   you can also raise the front bucket while cranking to relieve pressure ...


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## Cmp1 (Mar 2, 2016)

BriarPatch99 said:


> Again I may be wrong but I believe the proportioning valve gives priority to the backhoe section over steering ...   you may lose steering if you try to steer while operating the hoe ...
> 
> I don't have a chart ... I'll see if I can find one ...
> 
> ...



Great idea, I'll have him check those screens, I'll let you know what he finds, he may not get to it in the am, too dain cold out,,,, sir I so much appreciate the help, I'll let you know if you ever have a problem with your hvac, h2o htr, range etc, let me know,,,, if you can find a flow chart, that would probably help alot,,,, IMHO the problem is you've got 1 pump that powers everything, alot harder to troubleshoot, instead of having a pump for each circuit,,,,


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## BriarPatch99 (Mar 2, 2016)

Give this a look .... appears to be the whole JD 410 manual...

Lot of reading ...

https://books.google.com/books?id=9...ere HYDRAULIC IMPACTOR VALVE function&f=false


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## BriarPatch99 (Mar 2, 2016)

Another... 

http://www.liberatedmanuals.com/TM-5-2420-222-20-3.pdf


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## Cmp1 (Mar 3, 2016)

BriarPatch99 said:


> Another...
> 
> http://www.liberatedmanuals.com/TM-5-2420-222-20-3.pdf



Thanks buddy, let me get some more java in me, and I'll definitely check them out,,,,


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## Cmp1 (Mar 3, 2016)

BriarPatch99 said:


> Give this a look .... appears to be the whole JD 410 manual...
> 
> Lot of reading ...
> 
> https://books.google.com/books?id=9...ere HYDRAULIC IMPACTOR VALVE function&f=false




If one of the relief valves was sticking, and it was over pressured, wouldn't you think that the line from the valve would be hot with no actuation of any controls, do these relief valves relieve internally?,,,, from what I can tell the main pump is fed fluid from the tranny pump, so if you had a screen plugged down stream of the tranny the pump would be starved of fluid, the screens are all on the return to the pump same with the filters correct?,,,,


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## BriarPatch99 (Mar 3, 2016)

The trans pump job is to spray oil over the gears of the trans along with the rearend gears and to remove the heat by moving the oil to the oil cooler near the front grill ... it is under pressure ... but as you can see by the type hose connection ... it is not high pressure ... not sure if the pressure comes from the trans pump or from the suction of the main hydro pump ...

The relief valve under the belly relieves back into the trans case ... not sure about the one on the pump ... I think it bypass back to the suction side inside the housing ... again not sure...

I would think that heat would be higher with a stuck valve ... that fluid is forced through a small orifice against a spring plunger ... the pressure has to overcome the spring/plunger  or it goes on its normal route ...

There is a hydro chart starting around page 2-1779 on the bottom link I posted ...  maybe it will help some ...


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## Cmp1 (Mar 4, 2016)

BriarPatch99 said:


> The trans pump job is to spray oil over the gears of the trans along with the rearend gears and to remove the heat by moving the oil to the oil cooler near the front grill ... it is under pressure ... but as you can see by the type hose connection ... it is not high pressure ... not sure if the pressure comes from the trans pump or from the suction of the main hydro pump ...
> 
> The relief valve under the belly relieves back into the trans case ... not sure about the one on the pump ... I think it bypass back to the suction side inside the housing ... again not sure...
> 
> ...




Thanks buddy,,,, was checking it out yesterday, and then there was a server issue, I'll try again later this Am,,,, I believe he's going to be busy this weekend,,,, I wasn't able to get to the part of the manual that shows the tranny, he says he has a manual but it doesn't have a flow chart, but I think I would look at the relief valves 1st, what do you think?


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## BriarPatch99 (Mar 4, 2016)

Did he ever get it to crank? 

Just something to think about ... you can get a pressure gauge from Northern Tools ... I believe a Valley brand that goes up to 3000 psi for around $20 ... a fitting or two from the hydro shop and place that in line ... you would be able to test pressure ...


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## Cmp1 (Mar 5, 2016)

BriarPatch99 said:


> Did he ever get it to crank?
> 
> Just something to think about ... you can get a pressure gauge from Northern Tools ... I believe a Valley brand that goes up to 3000 psi for around $20 ... a fitting or two from the hydro shop and place that in line ... you would be able to test pressure ...




Morning buddy, yeah he got it to crank, running great, I think he's going to pull out the relief valve under the belly today, he's gonna get the packings to rebuild the destroke valve, the servo is good, he can get all the packings but one, no longer available, kit isn't available, has to buy everything individually, he actuated the hoe to break pressure, at least his engine is good,,,, I'll tell him about the gauge, I want to know what the return pressure to the pump is downstream of the relief,,,, 

I was a jet engine tech in the A.F, so I have a little bit of knowledge, we used to say, knows just enough to be dangerous, lol, lol, lol,,,, 

I read somewhere that the pump is fed from the tranny pump, I want to know return pressure, low side pressure,,,, and if it is high there could be a restriction somewhere, I suppose if he could tie in downstream of the relief that would tell him alot,,,,if we could just get some better weather, do you think he should do a flow check? and where? Between the cooler and pump? Where would you suggest?,,,, 

I also read where this guy said that the 2 best days in his life were the day he got his backhoe and the day he sold it,,,, lol, lol


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## BriarPatch99 (Mar 5, 2016)

Not sure where to check low side pressure .. I was thinking high side to see if it was within normal range ... I'll have to think more on the low side deal ...  got be about and out all day today may be later tonight/tomorrow before I get back ...


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## Cmp1 (Mar 5, 2016)

BriarPatch99 said:


> Not sure where to check low side pressure .. I was thinking high side to see if it was within normal range ... I'll have to think more on the low side deal ...  got be about and out all day today may be later tonight/tomorrow before I get back ...



OK buddy,,,, was thinking low side just to see if it is high, if it is, do you think you could have a blockage raising the low side and not relieving? Have a good day,,,,


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## BriarPatch99 (Mar 5, 2016)

This is my thinking... no way to prove it other than putting a gauge in ...   

If there is a high pressure in the low pressure side it would blow the hoses as they are just clamps not fittings( I may be wrong)

 ... also if there was no flow to the main  pump there would be low/very little flow on the high pressure side ...

If he had to relieve pressure by moving something(bucket/hoe) to crank ... then there had to be high pressure lock ... not lack of fluid as if there was a blockage to the main pump ....


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## Cmp1 (Mar 5, 2016)

BriarPatch99 said:


> This is my thinking... no way to prove it other than putting a gauge in ...
> 
> If there is a high pressure in the low pressure side it would blow the hoses as they are just clamps not fittings( I may be wrong)
> 
> ...




Agreed, I think this pump is a dry sump pump being fed from the tranny, and he told me today that the old pump came apart, cracked the case and threw the bearings,,,, I didn't know that, can you believe that,,,,he's going to order that gauge mon, he has not checked the reliefs nor the screens, and when he checked the filter, he didn't actually take the filter apart to look for flakes, just did a quick insp, said he didn't see anything,,,, wanted me to ask you if you knew how to make a manual destroke assy out of the destroke that's there, do away with the solenoid? Hopefully we can get some pressures soon,,,,also he did say he had flow but he didn't time it, and he said it did seem to be slow, I told him it should be somewhere around 5gpm, he checked between the tranny and cooler,,,, said he will time it,,,, one other thing, he said he was told that he can't start it below 45deg because of the viscosity of the hyd fluid, he's using hy gard fluid, I've never heard anything about that, have you?


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## BriarPatch99 (Mar 5, 2016)

He may could rig up something like a stiff cable(PTO dump/cable like on a dump truck) ... with a push knob/lever to convert it to manual ... may could find one at a junk yard ...   

We don't get real cold down here ... but I never heard the 45 deg deal ... I know plenty of machines that do operate around here below that temp using that fluid ...


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## BriarPatch99 (Mar 5, 2016)

I just did a little reading on the Hy-gard fluid ... there are two different ones a low temp and a high temp ...  I doubt they even sell the low temp down here ...  20* is cool for us ... I would think 110* would be pretty warm to you guys ...


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## Cmp1 (Mar 6, 2016)

BriarPatch99 said:


> I just did a little reading on the Hy-gard fluid ... there are two different ones a low temp and a high temp ...  I doubt they even sell the low temp down here ...  20* is cool for us ... I would think 110* would be pretty warm to you guys ...



I'll take the warmth,,,,he also told me that the new pump didn't come with a destroke valve, he got a used one, I told him for around 50 bucks he can get the packings to rebuild it vs fabing a manual one, but that still isn't the main issue, we hit 42deg yesterday, and might hit 57deg by Tues, but rain, it won't fit in his pole barn, nor ours, if he could get it over here,,,, he needs to get those pressures and check the relief valves,,,, 

There's a guy a couple miles down the road with a 5th wheel, gonna try and get down tomorrow and see if we can borrow it, just to get it over here, more room for him to work on it here, and I need it anyway when the weather breaks,,,, he's got the stuff to fab his hoses so when he gets the gauge he'll be set,,,, 

Wanted to ask you if you deer or turkey hunt? Saw 2 herds of deer yesterday around 20 deer each, and a flock of Turkeys, I think I counted 14 redbeards,,,, btw, good morning,,,,


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## BriarPatch99 (Mar 6, 2016)

I deer hunt ... but have not turkey hunted .... but I may ... I see way more turkeys than deer ... may have to try a turkey before long!  

I like to fish ... but haven't been able to go as much as I would like !


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## Cmp1 (Mar 6, 2016)

I'll pm you,,,,


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## rospaw (Mar 10, 2016)

BriarPatch99 said:


> I deer hunt ... but have not turkey hunted .... but I may ... I see way more turkeys than deer ... may have to try a turkey before long!
> 
> I like to fish ... but haven't been able to go as much as I would like !



Briarpatch, I just have to give you a thumbs up for helping a fellow out. Really impressed ! You are all right in my book!


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## Cmp1 (Mar 10, 2016)

rospaw said:


> Briarpatch, I just have to give you a thumbs up for helping a fellow out. Really impressed ! You are all right in my book!



He most definitely is Allright, we're still waiting on a gauge, so we're far from finished, but I'm telling you he is one wonderful and helpful person, everyone on here is, and I am extremely grateful,,,,


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## xlr8ngn (Mar 10, 2016)

I took a peek at the very detailed manual briarpatch attached.  The pump is a variable displacement pump, and that is what controls the pressure.  There is no bypass valve, and what fluid is not immediately used by the system is routed by the pump back through the low pressure oil hydraulic cooler.  My strong feeling is the stroke control valve is stuck, preventing the pump from being variable displacement and making it put out full pressure all the time.  This also takes away the oil that is normally bypassed through the oil cooler, which cools the fluid.  It would also prevent the stoke control valve solenoid coil from opening the valve when voltage is applied from the ignition when the key is in the start position.


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## Cmp1 (Mar 10, 2016)

xlr8ngn said:


> I took a peek at the very detailed manual briarpatch attached.  The pump is a variable displacement pump, and that is what controls the pressure.  There is no bypass valve, and what fluid is not immediately used by the system is routed by the pump back through the low pressure oil hydraulic cooler.  My strong feeling is the stroke control valve is stuck, preventing the pump from being variable displacement and making it put out full pressure all the time.  This also takes away the oil that is normally bypassed through the oil cooler, which cools the fluid.  It would also prevent the stoke control valve solenoid coil from opening the valve when voltage is applied from the ignition when the key is in the start position.



This is what we thought, he is gonna get the packings for the destroke valve, but as far as we can tell, the pump is fed by the tranny pump it flows from the tranny through the cooler and to the pump, as far as we can tell, the destroke valve just breaks pressure for startup, now we could be totally wrong and we probably are, lol, lol, lol,,,, I believe, and we could be wrong but I think the relief valves relieves the pressure back to the pump, there's one down by the tranny, and one up at the pump, so at the very least he needs that gauge, it's on order, should be here by Saturday, that will tell us alot, he's got low flow out the tranny to the cooler also,,,, I told him I heard this guy said the 2 best days in his life were the day he got a back hoe and the other one was the day he sold it,,,,


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## xlr8ngn (Mar 10, 2016)

See if this helps.


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## xlr8ngn (Mar 10, 2016)

I think this is the relief valves you mention.  They are actually pressure control valves.


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## Cmp1 (Mar 11, 2016)

xlr8ngn said:


> I think this is the relief valves you mention.  They are actually pressure control valves.



Yeah we saw that, we thought that it was the destroke valve also at 1st, but he needs that gauge, and the low flow issue throws another thing in the mix, but that shouldn't be too hard to troubleshoot, he checked btwn the tranny and the cooler,,,, the hoe runs really good, engine wise, and when we had it going I didn't see it jerking or anything, no leaks and 4wd is really nice on a hoe,,,, and boy do I need to use it, well my boy anyway,,,,


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## xlr8ngn (Mar 11, 2016)

The low flow issue is because the pump is stuck in full pressure mode, and little of the fluid is being bypassed through the oil cooler.  If it was operating normally, there would be excess fluid the pump does not need and it routes it through the cooler where it is cooled and then back to the trans case.


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## Cmp1 (Mar 11, 2016)

xlr8ngn said:


> The low flow issue is because the pump is stuck in full pressure mode, and little of the fluid is being bypassed through the oil cooler.  If it was operating normally, there would be excess fluid the pump does not need and it routes it through the cooler where it is cooled and then back to the trans case.



We're thinking more of a blockage somewhere, the tranny pump pumps it to the main pump after the cooler, as far as we can tell, the main pump is a drysump we believe,,,,


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## BriarPatch99 (Mar 11, 2016)

I am glad you guys got some additional input about this tractor ... my memory from 25/30 years ago ... well they are just about all they are is "memories"  ...  odd how recalling stuff from the past is not always as clear as it should be ... my Wife reminds me of this daily ....

Hope you all get it digging like an armadillo in a flower bed!!!


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## Cmp1 (Mar 12, 2016)

I'll get back to you as soon as we get some pressure readings, I'll tell you what though this is really a pain,,,, the one thing I really don't understand is why JD didn't go with gauges in the cab, if I were to buy a hoe it definitely wouldn't be a JD,,,, just saying,,,,


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