Rear Hydraulics and Tilt Cylinder Lengths

[Bob11x]

Good thread - thanks for the link!

Like TheOldHokie said, it's easier to tap the PB pipe on the loader valve. I had already installed fittings when I did my 3rd function install. All I had to do was move one hose from returning into the PB loop after the 3rd function and use it to feed the remotes, then one new hose from the remotes back to the loader valve, and one small line Teed into the tank line. I'll look and see if I have pictures on my computer, otherwise, I'll snag some today.

Dual rear remotes on my B2650

I see there is some interest in my remote project, which is great. I have to apologize for the lack of pics now. A while back when trying to up load pics for a new thread, I some how deleted all of the pics on all of my threads which was extremely disappointing to say the least. I didnt know it...

www.orangetractortalks.com

This thread is what made me join OTT, read from post #99 on and you'll see Dan and I's exchange with pictures.

 

[Bob11x]

Okay - So I was able to get a used BH77 Installation kit from where I bought my tractor -another trade in that didn't have a BH but had the kit and the dealer allowed me to swap out parts.
I Installed a Summit 3rd Function valve at the same time. Everything went well.

I removed the BH hardline from the PB port that bolts to the BH frame and I installed a SAE 8/JIC adapter with a JIC/JIC 90*into the PB port of the loader valve, and ran that to the 3rd Function valve on the loader frame.


I also changed the bracket location - the Summit bracket must be a multi use, and where it was to mount put it out in harms way:


I located it on the backside of the loader frame and drilled a new hole in the bracket - it seems much happier:



I brought the T line from the Summit valve back to the location where the BH hard line was bolted to the frame. I made a small bracket and installed a JIC/ 1/2 MNPT bulkhead fitting, added a 45* MNPT to install the original BH quick connect


I have the BH Hard line that returns to the 3PT on top of the transmission:



Everything seems to be good. I have a question in the next post.

 

[Bob11x]

I needed to post the above before it disappeared on me. I tried once a couple days ago and it went poof!

I thought I had a pretty good understanding of the hydraulics, but I would like to put on some rear remotes. I have read thru the B2650 posts and have some questions.

I think I need to mount a valve, take the line that feeds the backhoe (from Summit 3rd function T line) and put that to the new valve inlet? The valve has a T line and an adapter for PB. What is the difference in that? The third function valve only has a PB in and a T line that feeds the BH. Why are there Inlet, T and PB??

Thank you!

 

[Russell King]

The valves are open center valves on most Kubota tractors, the larger tractors and industrial equipment may be closed center valves. Open center means the flow created by the pump just passes through the valve. That flow is not high pressure until you activate a valve spool and divert the flow to a cylinder or other device.

The flow enters the valve in a Power Inlet port. Each valve has an Inlet port. The flow goes through the valve and should exit the valve through a Power Beyond port. (There are sleeves to install or plugs to insert to convert a Tank Return port to a Power Beyond port). This flow path must NOT have any Tees in it. So a PB port is used to avoid putting high pressure on internal cavities of the valve that aren’t designed for that pressure. This flow path should end with the three point valve to dump into the tractor sump, sometimes Kubota has internal passages and manifolds to make the routes internal to the tractor but that is on larger tractors usually.

The Tank Return port is to handle the flow that is returned by the cylinder when the opposite side of the piston is being pressurized. It is relatively low pressure fluid and will be dumped directly into the sump. The Tank return lines can be Teed together.

A Kubota backhoe valve usually does NOT get a PB sleeve since you can’t use the three point hitch when you have the backhoe installed and the backhoe valve is removed when the backhoe is removed. So there is no way to build up pressure inside the valve body of the backhoe valve. The backhoe valve MUST be the last valve in the chain before the three point return. Usually there are two connections on the tractor that must be connected together to complete the flow path when the backhoe is removed.

 

[Russell King]

If you are using any pipe fittings in your hydraulic system you should replace the pipe fittings. You can use pipe fittings on the low pressure tank return but why would you when you can just use hydraulic fittings and not worry about having any pipe fittings involved at all?

Most people also avoid Teflon tape products on hydraulic systems also. There is a possibility of the tape becoming lodged in a small passage.

I personally avoid all NPT threads in a hydraulic system and use JIC connections or SAE port connections (or BSPP port connections on the Kubota tractors).

 

[TheOldHokie]

I think I need to mount a valve, take the line that feeds the backhoe (from Summit 3rd function T line) and put that to the new valve inlet? The valve has a T line and an adapter for PB. What is the difference in that? The third function valve only has a PB in and a T line that feeds the BH. Why are there Inlet, T and PB??

Thank you!

The technical answer is a bit too complicated for a full answer. Here is the Readers Digest version.

The 3rd function valve is an industrial type valve and the T port can supply full pressure to a downstream valve.

The T port on your AUX valve is limited to roughly 500 PSI so it needs to have an additional outlet for high pressure carry over (HPCO) for the downstream valves. HPCO is a also known as power beyond.

Dan