pto pump to a mahindra 3710 backhoe

[100 td]

When the pump is operation, hydraulic flow needs to go into the valve block on the IN or P port and it needs to exit the PB port. So when running, FULL FLOW EXITING THE PB PORT ALL THE TIME with the valves centered. When you operate a valve, flow out the PB line stops, and now goes to the allotted cylinder AND EXHAUST flow exits the tank line from the opposite side of the cylinder. When it comes to end of stroke (or relief pressure is exceeded), flow exits via the tank line via the relief valve if the valve is held, until the valve is released and then full flow exits the PB port again. Make sure you don't have PB and P around the wrong way.

 

[Billself]

Ok thanks i'll make sure everything is hooked up correctly and run the PB to the tank along with the return line. let you guys know how it turns out. thanks again

 

[oldnslo]

the top part of the relief valve with the allen head is the pressure you have. what does the bottom spring do for the valve, keep the fluid traveling through at higher pressure or what?:confused2:

Bill,
Depending on the style of relief you can two or more springs. The top adjustable spring may be the pilot spring on a pilot operated relief. When the pressure is reached the pilot opens which then vent the main poppet held by the lower spring. The main poppet then passes full flow. In reading through this post I am very concerned that your relief valve is not working since it should have opened and prevented the stalling of your tractor.

With the PB uncapped you should all the functions fully operational IF everything is connected properly.

BEFORE trying to operate this again do like 100 td said and triple check ALL of your connections to this valve.

 

[Billself]

Well this took a while but i think i got it. first let me say thanks to all who gave advice. Ill tell you what i did i went a head and ordered a inline relief valve,opened up the power beyond and went with a 1" hose as feed hose then 3/4 hose off the inline relief valve back to tank then routed the power beyond back to tank and of course return back to tank. but then i had to play with it a little to find out that the old relief valve someone did mess with it,my factory rel;ief valve was set from factory at 1500 pounds pressure so i turned the old relief until it started to flow through relief then backed it off a touch just enough to play, found out that there was way more fluid than i needed and was getting extremely hot so shut it down and waited until i put a cooler on the front of tractor in front of the radiator.Also put quick connects on it so when i took the backhoe off everything would be good to go I havent had time to play with it yet to find out if it still gets to hot but anything would be better than fluid to hot i still don't understand why its so hot. I have three lines returning to the tank and one big 1" feeding. I think its because i have way to big of a pump for this application what do you guys think?


PS. the pto pump is a 7gpm at 540 rpm I should have used a smaller one but could not find one

 

[LouNY]

everyone has given you good information on plumbing the valve and the returns,
I also see that you have a 7 gpm pump when it is run at 540 rpm,
you should not have to run your tractor at pto speed, throttle it down to half to two thirds rpm.
Your flow rate will drop dramatically, many time you can operate smoother with less flow.

 

[Billself]

when i throttle down below 2000 rpm on motor it wants to kill the motor when i dig

 

[Billself]

I know its been awhile but finally got to finish the oil cooler for the backhoe I used a larger hydraulic hose to return my power beyond to the tank and the return goes through the cooler before going back to the tank however it still gets a bout 150f i know thats a little warm for it but if all else fails i can double up on the cooler or put one in front of the other to help keep it cooler i would like to have it about 100 degrees but ill take what i can get i ran it about 2hrs today and 150 was about it. so ill take that for now but when the summer heat gets here again i'll have to come up with something different THANKS for all the help i appreciate it. if anyone has a good idea to cool the fluid even more i would be interested in hearing about it Thanks again

 

[Everhard]

Quick question - was this hoe originally designed to run off a pto pump? If not is there a reason you didn't run it directly off the tractor's hydraulics? (I've got a NH hoe that I hooked up to my Ck20s directly to the rear remotes.) Sorry, not an answer to your question, just curious why you went down this road.

E.

 

[Billself]

I didn't have rear remotes for mine and i didn't trust the hoe fluids in it been sitting for awhile so i thought it would be just as easy to put on the pto boy was i wrong if i had it to do over i would have put it to the tractors hydraulics

 

[Everhard]

I guess my first thought is how much more will you have to do/spend to get this working right? Before I added rear remotes I had the same thought as you and debated going pto pump but in the end I went remotes. (Factory single set) Now I'm adding a 3 spool because one set isn't enough!
I would suggest you consider what you want to be able to do now and in the future and decide if having remotes is of any use for you. If so my suggestion would be don't get the factory remote as you should be able to add a 3 or 4 spool for less money. (I'll be able to confirm that hopefully in the next week or so - once I've got mine done. lol!) I know if I was to do this over again I'd likely not bother with the factory remote - other than the control is of course in the perfect position the cost being the same as getting 3 or 4 remotes negates that advantage.

E.