Hydraulic connection question...

teg · Oct 8, 2010

What is your best guess as to the line from PB block and going into the loader valve of an L2800. See photo. Also in the photo, on the side of the valve... there is a plug, I'm guess so you can plumb from the top or the side... Can I put a 5000 psi pressure gauge in that hole??

I have my hydraulic "shopping cart" full except for this last piece. Once out of the valve (which is SAE 8) I'm plumbing everything with NPT 3/8". Any problems with that?

Edit: Grand total was ~ $390 with 2 spools working, the other is capped till needed.

J_J · Oct 8, 2010

If you have a hose from a PB outlet, it probably means it is going to another valve downstream. As far as the hole /plug on the side. It looks permanent to me, and a little weld on the edge of the plug. If a valve has a port that can be used, it will have a threaded plug or a plug with a hex insert. Some valves have two inlets and two outlets. You should install a tee and a pressure gage before the first valve. The first valve will normally control the relief for the system.

The fitting is either 3/8 or 1/2,. Need a reference to establish the size from a picture.

Craig Clayton · Oct 8, 2010

Sir
If you disconnect your top ORB you can peek in and see if there is a common passage. I have taken valves with unknown passages and mapped them to a full understanding. I lay them down on a piece of paper with the spools removed and using soft wire mark each indent on the paper. Then mark each access port on the paper. Then pock soft wire through each passage. When you lay the spool on the paper pattern you can then see how the oil redirects as the spool travels. It does take an hour or so to build a paper Xray. As an electrician I do the same process with a switch just I use an ohm meter.
Craig Clayton

teg · Oct 8, 2010

J_J said:
...Need a reference to establish the size from a picture...

I thought about that this morning... :ashamed::confused2: I'm pretty sure the hose coming in is 3/8" so it stands to reason, 3/8" fittings... If it doesn't fit, I'll try and pickup that part locally. Thanks for your reply...

Gary Sweat · Oct 8, 2010

It looks to be an ORB to NPT fitting due to the small flat ring at the base of the fitting. If the hose is 1/2" then it will likely be an SAE10 ORB to NPT. If the hose is 3/8" then it will likely be SAE8 ORB to NPT. That's the way they are on my loader valve. Pump, PB and tank are SAE10 ORB and the cylinder ports are SAE8 ORB. Here is a photo of a SAE8 ORB to NPT swivel. Your fitting looks like it has a male threaded end but it is probably the same type.

teg · Oct 8, 2010

I ordered this to go into that port: SAE 8M x 3/8 NPTF 90 SWIVEL

...and was hoping to use that connection on this new valve: 3 SPOOL 8 GPM PRINCE MB31BBB5C1 DA VALVE
(great, on a side note, I just noticed I bought the 13th one... that's for good luck, right???)

I'm not familiar with "ORB"... to tell you the truth, I'm not expecting to get this right the first time... my tractor is 3 hours away so I can't check on this...

Another question I have, is the lines going to the Quick Disconnects are 3/8" but I think the grapple is 1/4"... is that going to be a problem?

I didn't buy supplies for the last spool for a reason... just in case I need to change my plan around.

J_J · Oct 9, 2010

Some people use smaller hose to reduce the speed of operation of the grapple. . On the ends of the grapple hose, have the hose maker put on whatever will connect to the QD's. Just tell him what you have and what you want. Take in a QD in necessary. If you are going to make up your own hose, then use whatever fitting to go from 3/8 QD to 1/4 hose. In order to further slow the grapple, then a needle valve could be used.

Gary Sweat · Oct 9, 2010

teg said:
I ordered this to go into that port: SAE 8M x 3/8 NPTF 90 SWIVEL

It will work if the port is SAE8. If it's been in the valve for a long time, I would replace the "O" ring. The o-ring is what actually makes the seal. I can't tell for sure from the photo if the hose is screwed directly onto the old 90 fitting or there is an adapter after the 90. If the hose is screwed onto the 90 then you are going to need a NPT to NPT straight fitting in between the hose and the new 90 as the new 90 is a swivel and the old is a straight male end.

As for the 3/8 to 1/4 grapple issue, I will have to leave that up to those who know hydraulic flow to answer. I get lost when it comes to flow, restrictions, turbulence and such. I just try to keep everything the same size and hope it works.