Power Beyond vs Series for loader valve?

[winston1]

No response to my email to Akon. OK, guru's, based on my pictures and description of my valve, is there any way for you to know if a plug in that top inner opening could convert me to power beyond. I think I am crafty enough to come up with a plug if that could be the answer. Or is there some testing or something I could do to give a better handle on how my valve works?

Possibly something like this. I could cut a slot in the hex part for a screwdriver? http://www.ebay.com/itm/2-M16-1-5-x...408&pid=100011&prg=1005&rk=1&sd=400169542285&

Also plugs available with alan heads but I really think I need a gasket surface.

 

[oldnslo]

Companies Like Parker Hannifan, Zero-Leak, Eaton-Aeroquip, etc all make metric plugs. Do you have a Parker store or another hydraulic shop that carries fittings in your area?

 

[winston1]

Companies Like Parker Hannifan, Zero-Leak, Eaton-Aeroquip, etc all make metric plugs. Do you have a Parker store or another hydraulic shop that carries fittings in your area?

Probably do, but do you think a plug or a sleeve of some kind is what will have to be in the opening?

 

[California]

Take a look back at posts # 39 and 40. I posted a picture of the plug that came with my new valve but I think it's more likely you need one like JJ's second picture where the plug has an upper and lower shoulder, each with an o-ring.

The theory of operation here is that the return, drain, from the descending cylinders is normally combined inside the valve with the PB fluid that went straight across the valve. Then this new plug separates the two flows so pump pressure goes out the PB and minor pressure from the cylinders dropping goes out the Tank exit.

If you can see some way to isolate the two flows you've solved the problem. (Plus plumbing from Tank outlet to transmission return hole.)

 

[California]

I recently puts a new o-ring seal on my lift piston. It will now stay up ... for days. However, when the tractor is in use with the load in the up position it will very slowly descend and after a small descent it will raise back ... don't know why it does it when running, yet, won't do it when sitting.

One possibility is the lever is too far back and the cylinder isn't totally isolated. If you can attain a perfect seal when parked, then maybe mark that position and use it while running?

Or - the implement is so heavy that fluid goes out the relief valve when you hit a bump driving around? My backhoe does this.

 

[oldnslo]

Probably do, but do you think a plug or a sleeve of some kind is what will have to be in the opening?

Since it threaded I would say yes. It would be kind of difficult to have a fitting with two different thread sizes line up perfectly so that they would screw together. Without having the valve in my hand I can not gaurantee this 100% though.

Can you tell where the tank port and PB port connect in the valve body compared to where this internal plug would go. It should isolate those two flow paths while allowing the pressure port to flow to the PB port. That is how the Prince LVT valves are made.

 

[winston1]

One possibility is the lever is too far back and the cylinder isn't totally isolated. If you can attain a perfect seal when parked, then maybe mark that position and use it while running?

Or - the implement is so heavy that fluid goes out the relief valve when you hit a bump driving around? My backhoe does this.

Doesn't matter what height the 3 point is at when running. Just setting still with a load it will very slowly ease down until the lift catches it and raises it a 1/4" or so. I don't mean a few seconds, more like minutes before it does it. If the tractor is off it will set at any height and hold it there for days. I know that probably doesn't sound right but I'm telling you that is what it does and I'm sticking to it.

 

[California]

If anybody's still reading my portion of this thread ...

I plumbed in a pressure gauge in front of the new loader valve to see what's going on.

Ghenges, JJ, and others who recommended against plumbing in series have it right - the pressure at the input side of the valve can go to the SUM of the loader valve and the 3-point's separate relief settings under certain conditions (which are best avoided!).

The new Prince loader valve properly bypasses at 2000 psi when the loader cylinders reach the end of their stroke. And separately, the 3-point lift bypasses at 2300 psi at full lift. (Should be 2000 per the manual). You can hear the engine load down a little.

Returning the lift lever to Hold (slightly forward) brings the gauge down to 50~500 psi and the engine doesn't sound loaded. If the lever is set for -0- psi the lift settles down, imperceptibly slowly. (Like Winston observes).

But - lift lever at Lift postion, full up, and one of the loader cylinders at its end where the Prince valve is bypassing through its relief, and I saw the gauge pinned hard, probably 4000 psi. And the engine is clearly working harder. Don't Do This is the obvious lesson. I think the loader valve is facing the full 2300 psi back pressure 'downstream' regulated by the lift valve's bypass. Prince's install instructions allow only 500 psi back pressure.

I have avoided doing that (Lift and loader valves used at the same time) since I bought the tractor because it didn't sound right. I'm going to leave the Prince valve in series like the old AICO valve was for the past 30 years, and I'm going to leave the gauge mounted so I have more precise information.

 

[Scotty Dive]

I am surprised we do not have more failures. I am still digging out from 30 inches of snow and can tell you that using a back blade and the front end loader at the same time is pretty common place.

 

[Normmm]

What about one of the trans drain plugs. It says it will handle 500 lb back pressure so it doe not have to return to the top os the tank.