Loader Adjusting the relief valve

[JC-jetro]

JC, are you talking about the valve circled in red on the photo below? I believe this valve has the output of the main hydraulic pump routed to it. It's the valve with the pressure relief on the bottom and has a shim kit listed in New Holland's parts list. If it is set at a low value, any relief valve after it will not be able to raise the pressure. It's possible that your tractor doesn't have this since I think these were not added until later in the model line.

Jim,

You are right and I do not have the block you have circled. I'm sure that is for the later model with a loader. I can't see two relief pressure in series unless there is a design reasons for it. On high pressure steam line I reduce it on several different levels based on design need ( 100 psi or lower for steam to hot conversion, to 30 psis for sterilization and around 10 psi for humidification). I don't know if in tractor hydraulics they do the same or not. Obviously here you want the highest pressure and flow available to loader and then 3 point system.

I wanted to stress Mark that there is always a way to up the pressure either adjustment or shimming but should not attempt it unless he knows and verified operating pressure. On mine , if I had a loader then the extra loader hyd block would be sandwiched between the relief device and the lift spool. In that case there would be only one adjustable relief device. I think somewhere in my thread I have a pic of 1700 relief device that Mark can check.

JC,

 

[jinman]

Yes JC, the 1710 models after 1983 had the pressure relief block (diverter valve actually). Once that pressure is set, any additional pressure relief can only adjust the pressure lower. Here is a hydraulic diagram of the 1710 with item 48 being the diverter block. The pressure adjusting shim kit is item #58.

 

[JC-jetro]

Yes JC, the 1710 models after 1983 had the pressure relief block (diverter valve actually). Once that pressure is set, any additional pressure relief can only adjust the pressure lower. Here is a hydraulic diagram of the 1710 with item 48 being the diverter block. The pressure adjusting shim kit is item #58.

Good info Jim:thumbsup:, I'll be curious to see if he has the additional relief device, most probably not. Mark now should have all he need to evaluate the situation and adjust the pressure if it is warranted.

JC,

 

[mostly_gas]

mfuller, You not only need pressure but volume as well. There was a reason the backhoe had it's own pump. I would not be surprised the pump you took off had a larger flow rate and that accounts for the speed difference.
I have a 1700 w/ 770 loader and it does the same thing , not enough force from the main lift cylinders to raise the front end, but the curl cylinders will.

 

[mfuller]

Sorry it's been so long between posts. I've worked 12 hrs overtime this week so far. OK, I got a gauge, checked the pressure coming out of the aux port. With the rpm's about midrange, the gauge reads 1700 psi. The loader is rated at 1600 psi. I do have the diverter valve circled in red. Mostly Gas, the self contained pump was rated for 4.5 gpm, my 1710 is rated for 7.8 gpm. But, I'm not as concerned with the speed as much with force. I know that relief valves in series can only reduce the pressure, not increase it. My big question now is, how do they get the full 2133 psi of pressure to the 3ph if the diverter valve for the loader drops it to 1600-1700 psi?

 

[JC-jetro]

Sorry it's been so long between posts. I've worked 12 hrs overtime this week so far. OK, I got a gauge, checked the pressure coming out of the aux port. With the rpm's about midrange, the gauge reads 1700 psi. The loader is rated at 1600 psi. I do have the diverter valve circled in red. Mostly Gas, the self contained pump was rated for 4.5 gpm, my 1710 is rated for 7.8 gpm. But, I'm not as concerned with the speed as much with force. I know that relief valves in series can only reduce the pressure, not increase it. My big question now is, how do they get the full 2133 psi of pressure to the 3ph if the diverter valve for the loader drops it to 1600-1700 psi?

Mark,

Let's verify first if you have a relief device passed your diverter valve. look at the pic below, do you have them on your 1710?
If you do and diverter comes first then You'll have an issue, as you can keep stepping the pressure down but once down can't step up real easy. follow plumbing and inlet and out let to the pump and see where your reliefs are. I would think you might have a main relief like pictured below to 2133 psi and diverted block steps it down to your loader requirement at 1600. doing so you'll have max rated pressure and flow for the 3 point implement and a lower pressure for the loader. I'm heading back home and should be able to post back later tonight if you have a question.


JC

 

[mfuller]

My tractor does not have that relief valve. It has a 3 bolt cover bolted on there. I was reading my loader manual earlier, it states that the loader can be used on a 1910 at full pressure (2133) or on the 1310,1510,1710 with an inline relief valve, which mine does not have. It also states that some of the remote controls for the loaders have a built in relief valve. Are we sure there is a relief valve built into the diverter block next to my right foot?

 

[JC-jetro]

My tractor does not have that relief valve. It has a 3 bolt cover bolted on there. I was reading my loader manual earlier, it states that the loader can be used on a 1910 at full pressure (2133) or on the 1310,1510,1710 with an inline relief valve, which mine does not have. It also states that some of the remote controls for the loaders have a built in relief valve. Are we sure there is a relief valve built into the diverter block next to my right foot?

Mark,

You must have a relief valve somewhere downstream of your hyd pump before any branches or implements. there are two reasons for it. What establishes system pressure is an obstruction to cause the pressure (adjustable) on a gear pump. Secondly this pressure needs to be controlled (maintained constant) so you would not dead head a positive displacement pump, that's where the relief comes. Spring in the relief maintains adjustable system pressure and above that it relives to maintain max pressure. Pump internal mechanism including seals are designed for a pressure so if you go above it it can damage it. You must have an adjustable relief as party of you hyd block like Jim stated. Shimming in the diverter block would increase your system pressure.

JC,

 

[mfuller]

Hey, all. Just an update. I added couple of shims to the relief valve in the diverter block. Pressure went from 1700 to about 2150. The back hoe now works much better. I did, however, blow a hose on the hoe, but, if it couldn't handle 2150 psi it needed replacing. The hose was rated for 3000 psi, I went ahead and replaced it with a 4000 psi hose. If anymore go I will replace them with the better hose also.
Thanks to all those who offered advice. It sure made it a lot easier.

 

[JC-jetro]

Glad it all worked out. The busted hose was probably old and needed replacement anyway.

JC,