Power Beyond vs Series for loader valve?

[Car Doc]

No, no inspection plate, or extra space on the shifter. I think creating a return port would mean drilling the transmission casting. Doing that competently is beyond what I can do. I don't see an alternative to returning at the dipstick hole, and I have no idea how to provide a dipstick after that.

If you decide to do it which may not be necessary if it worked before satisfactorily 10 years.

Nipple, a tee,plumbing in to the tee, a pipe plug on top of tee and that is what gets drilled and a dipstick added to that. The fluid level should be correct if its right before you do the new valve or compensate as necessary. Obviously the pipe plug would have to seal and a wrench used every time to check it not as handy as before but workable. my .002

[J_J]

Excerpt from Prince web site.


Q: I just put a Prince control valve on and it’s leaking out the back of the valve. What went wrong?

A: There is a very good chance that the outlet line (return to tank line) has been pressurized. Just one tank line spike, over 300 psi, can cause the valve to leak at either the handle or the spool end cap.

[California]

Wow. That would be my luck.

Is there another series of valve more tolerant of serial plumbing - as recommended in my Yanmar manual, and as used on my old valve?


In my research I found Chief valves on Baileynet.com that were only $148 for two-spool and $185 for 3-spool. (Both have float on first spool). I would have needed hose size adapters including two elbows, PSI reset down to 2,000, some kind of new mount to get the side inlet away from my throttle, and I couldn't find detailed specs (maybe cheap unsupported generic Chinese junk like HF???) so I moved up to this Prince LVT at $215 thinking it was the better buy. Now I wonder if those would work just as well. Has anyone used them?

[winston1]

I am certainly no hydraulic guru so please take my comments as trying to learn and not teach. California, am I correct in thinking your loader was dealer installed? I know for a fact many and probably most of the vn tractors with loaders are plumbed just like yours (through the loader valve and then the 3 point). My vn is plumbed that way and believe me it has been tested with a load on the 3 point. My joystick does not have a power beyond outlet. Said all that to ask the question: Are there any loader valves made to work like California's is currently plumbed?

[brain55]

Here is my practical experience. I started working at a Kubota dealer in the mid-eighties. At that time we were selling a lot of L345's and L355SS's with 1720 loaders with the loader valves plumbed in series. These were big Cross valves with significantly more flow capacity that those tractors put out. They were having a problem with leaking seals on the spools, the factory reps came and had us convert them all to power beyond. The problems went away and I never plumbed a tractor in series again. They explained the problem as pressure stacking not a back-pressure issue. So whatever line pressure there was to the 3-pt increased the relief valve pressure in the loader valve by that much. I can't swear to the physics behind that, but I can swear to the results we saw.

Brian

[California]

Winston I'm pretty sure this Great Bend (now Bushhog) loader was dealer installed when the tractor was new. I was told the tractor was bought for mucking out a riding stable daily. It has the optional heavier 'loader-ready' front axle.

I too am curious if there is a different brand of loader valve designed for series plumbing.

Brian the stacking, doubling, of pressure makes sense. But I think it also means that the doubling can be avoided by never having the 3-point under pressure in its Lift position while using the loader valve. (3 point Hold position puts no load on the pump). And it certainly makes sense for a quality dealer to adopt 'best practices', and avoid warranty returns caused by shortcut procedures. If I had an external Tank Return port on the transmission I would definitely convert to separate PB / Return plumbing from the output side of the valve, but I don't.

[ghenges]

Here is my practical experience. I started working at a Kubota dealer in the mid-eighties. At that time we were selling a lot of L345's and L355SS's with 1720 loaders with the loader valves plumbed in series. These were big Cross valves with significantly more flow capacity that those tractors put out. They were having a problem with leaking seals on the spools, the factory reps came and had us convert them all to power beyond. The problems went away and I never plumbed a tractor in series again. They explained the problem as pressure stacking not a back-pressure issue. So whatever line pressure there was to the 3-pt increased the relief valve pressure in the loader valve by that much. I can't swear to the physics behind that, but I can swear to the results we saw.
Brian

Thanks Brian

Now, that is a head exploding explanation that must be stored in the ole data bank.

[Neat 1500]

My return to tank is an extension piece that screws into the trans fill plug hole in which the cap then screws on top of the extension then it has a threaded hole for the hydraulic hose to go in. i have even drilled another hole in the side if it, tapped it and added a filter for a breather which has reduced my oil blow out around the gear shifter.

[Scotty Dive]

California - I wish I could help you out since you provide so much great info. The only thing I can add is that I was having problems with power on my V2 loader - plumbed in series. I put a gauge right at the loader to see what was going on. It was a 3000 psi gauge. My three point was not adjusted correctly and when I had it all the way up and while using the loader I was seeing pressure spikes that buried the gauge well over 3000psi. So far I did not break anything, but I want to share that the pressure spikes can be significant and I am thinking even on a properly adjusted 3 point, its possible to have a branch or something snag the adjusting lever and receive a pressure spike.

Also - Hoye includes a part number HA-39 in their power steering kit that allows you to easily dump into the oil dipstick hole - See the Power steering instructioions here: http://www.hoyetractor.com/techhelp/...STRUCTIONS.pdf

[Car Doc]

Good job Scotty nice find! I wonder what the flow rating would be as far as dumping the loader thru it? If a large enough fitting would fit the adapter say a straight instead of a 90 (looks like a 90 in the pic) that would increase flow alone? Just thinking out loud for the next instance this comes up.