Adding a spool valve on a 70D

Although I have done searches on this and other forums, I want to make sure I have this correct.

I want to add a single spool valve to my 70D to control the loader hydraulics (just the one set of cylinders, no power bucket), leaving the Powr-Trol to operate the rockshaft.

I am getting a 4-position valve with power beyond capabilities. I will plumb the pressure line from the pump into the spool valve, the power beyond will go to the pressure side of the Powr-Trol and the output will T into the return line to the pump.

I'm afraid I still don't understand the power beyond, is above the correct application for it? I don't need to operate both the loader and the 3-point at the same time. Is it okay to T the spool return into the return line from the Powr-Trol? Has anyone done this before and have pictures about where/how they mounted the spool valve?

Thanks.

A local guy had a 60 that he'd modified - he cut the pressure line near the hand clutch lever, brazed on two elbows, then plumbed in an open center valve with rubber hyd hoses. He mounted the valve on the right axle housing with linkage to a lever up near the seat. It looked very neat, in spite of my description.

The service bulletins show a valve installation, and the valve is mounted on the left side of the battery box (below the seat). The pressure line is modified under the floor plate to feed the valve.

You need to be aware of the pressure relief setting - you could damage your pump if the setting on your new valve is too high.

Not sure of your battery or pump location on your 70 - never been around one.

Keep us posted on how you do it.

"I am getting a 4-position valve with power beyond capabilities. I will plumb the pressure line from the pump into the spool valve, the power beyond will go to the pressure side of the Powr-Trol and the output will T into the return line to the pump."

I read your post again - there should be 4 openings on your valve;

1 for pressure from the pump
1 for power beyond to the powr-trol
2 selectable outputs for your 2 way loader cylinders

I don't understand your comment "the output will T into the return line to the pump". I don't think you need to fool with the return line to the pump. It will return on it's own through the powr-trol. Your reservoir is in the powr-trol unit, and your "power beyond" opening on your new valve is essentially returning fluid to the reservoir.

The service bulletin that I referred to in the earlier post is SB222 from December 1954.

One does not need PBY just cut pressure line, insert control valve in series as PJH stated. Put a plug in the PBY hole

All you need is a simple ,open center valve ,it only needs one - way pressure & a open no pressure return ; or a float position ; 45 Loaders are NOT to be used with 2-way [down pressure on cylinders ] return oil in cyl. is only used to increase oil capacity in power-trol, on 50 thru 70, A,B.. In 45 parts cat. Char-lin valve is used with bypass relief valve to return oil to power-trol...(Adapter Y1904c may still be some out there) pic.... Info. [post] from archives on YT.. I think this is valve ,PJH is referring to in SB222.

I did pretty much the same thing on a 730 diesel. I cut a piece out of the pressure line,threaded each end to half inch pipe. It was real thin,so I used black pipe fittings and brazed them on. The I ran a hose from the line from the pump to the "in" side of a 2 spool open center valve,and another hose from the "out" side of the valve back in to the pressure line. I didn't do anything to the return line at all. I made an "L" shaped bracket and mounted the valve right up beside the throttle.

You need to be aware of the pressure relief setting - you could damage your pump if the setting on your new valve is too high.

Click to expand...

I planned on using a spool valve with a 1500 psi relief valve, will that be sufficient? (taken from here http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=jd&th=437088)

I read your post again - there should be 4 openings on your valve.

Click to expand...

On my valve, there are 5 opening, all ports you listed along with one additional for a return directly to the reservoir or sump. This shows my ignorance with how Power Beyond and Powr Trol works. My line of thinking was that Power Beyond is designed to be used with another valve after the spool valve, which is what the Powr Trol is, but it is also the reservoir, so I wasn't sure.

From this thread http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=jd&th=259784, I got confused.

One does not need PBY just cut pressure line, insert control valve in series as PJH stated. Put a plug in the PBY hole.

Click to expand...

Okay, wasn't sure. Fixerupper in this thread (http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=jd&th=437088) indicated to use the Power Beyond to the Powr Trol, but I see what you are saying. In neutral, the open spool should run fluid at full pressure to the Powr Trol.

All you need is a simple ,open center valve ,it only needs one - way pressure & a open no pressure return ; or a float position ; 45 Loaders are NOT to be used with 2-way [down pressure on cylinders ] return oil in cyl. is only used to increase oil capacity in power-trol, on 50 thru 70, A,B.. In 45 parts cat. Char-lin valve is used with bypass relief valve to return oil to power-trol...(Adapter Y1904c may still be some out there) pic.... Info. [post] from archives on YT.. I think this is valve ,PJH is referring to in SB222.

Click to expand...

I had my cylinders redone at a local hydraulic shop with new rods and seals (not original or JD parts) so that I can use them with down pressure. The valve also has a float position on it as even if they cylinder are now able to handle the down pressure (although I understand the originals were not) the rest of the frame isn't really designed to do a lot of heavy digging.

I appreciate all of the help, I just wanted to make darn sure I was doing it correctly as I do not want to have to do it again, or break anything on the tractor.

I had thought of taking the high pressure line off completely and redoing it with flexible lines (in case I ever wanted to make it strictly a parade tractor I wanted to avoid cutting into the lines). I see from the 45 parts manual that they made an adapter into the pump and back of Powr Trol (Y1904C). Anyone know where I can get this part?

Thanks again for all the help.

Teeing into hyd systems works correctly on closed center hyd systems but doesn't work correctly on open center hyd systems.

The original lift cyl.'s on 45 loader , will work fine as double acting, [down pressure] BUT JD engineers , only designed hyd. hookups single acting,; 20 & 30 series two cylinder's only used one hose to lift cyl. & custom power-trol then was set to single acting. Welds on loader frame will fail,& from experience I can say studs in tractor axle, with mounting brackets on them will break or pull right out of axle... For adapters I'd get some used hyd. press. line [salvage yard, all 50 thru 730 etc, used them] cut them & braze on 1/2 " black iron couplings ... save your original pressure line,,...

Teeing into hyd systems works correctly on closed center hyd systems but doesn't work correctly on open center hyd systems.

Click to expand...

Right, I just planned to T into the return line for the "return" on the valve. However, now it sounds like I can just run the return right into the Powr Trol, ignore the PBY port and everything will be good. If I T into the pressure line, I won't get any pressure build up in the spool valve.

(quoted from post at 11:00:42 01/18/15) The original lift cyl.'s on 45 loader , will work fine as double acting, [down pressure] BUT JD engineers , only designed hyd. hookups single acting,; 20 & 30 series two cylinder's only used one hose to lift cyl. & custom power-trol then was set to single acting. Welds on loader frame will fail,& from experience I can say studs in tractor axle, with mounting brackets on them will break or pull right out of axle... For adapters I'd get some used hyd. press. line [salvage yard, all 50 thru 730 etc, used them] cut them & braze on 1/2 " black iron couplings ... save your original pressure line,,...

Click to expand...

Exactly my thoughts, I plan on having using the cylinders as double-acting but not really "using" them as such (not digging into anything, not stressing the frame, not treating it like a dozer, etc.). Where I live in Colorado, I don't have many salvage yards around so I think I will just have the slugs machined based on dimensions I take off of my pressure line.

The picture with the valve is of my G with a live hydraulic
pump. If you would like insturctions on how to do this from
Deere find a copy of the instruction manual for the 822 plow.
It gives instructions on how to add this valve to the 50 60 and
70 tractors. The Deere issued valve in the picture, it is a
Cessna valve, has a return line to the drain plug on the power
trol housing. If I can get over to the farm today I will take some
pictures of the 70 with a single spool valve on it..
Thanks
Ken

Here is a picture of the Cessna valve before I sent through it. Had to hand make a few parts for it. If anyone has an extra valve like this I need one more, I do not care if it leaks or works.
Thanks again
Ken

Since you are adding a float position valve go with the power beyond You have a phone number?

(quoted from post at 14:02:12 01/18/15)

Teeing into hyd systems works correctly on closed center hyd systems but doesn't work correctly on open center hyd systems.

Click to expand...

Right, I just planned to T into the return line for the "return" on the valve. However, now it sounds like I can just run the return right into the Powr Trol, ignore the PBY port and everything will be good. If I T into the pressure line, I won't get any pressure build up in the spool valve.

Click to expand...

It is Open Center. The extra valve is not T'd into the return line either. The extra valve is plumbed in series into the high pressure line from the pump. Why do you want to get into the tractor's return line ?
A relief line will be required from the relief valve port on the new valve back to the hydraulic reservoir.
1500psi relief setting is too high for the system. 1200psi is plenty.

It is Open Center. The extra valve is not T'd into the return line either. The extra valve is plumbed in series into the high pressure line from the pump. Why do you want to get into the tractor's return line ?
A relief line will be required from the relief valve port on the new valve back to the hydraulic reservoir.
1500psi relief setting is too high for the system. 1200psi is plenty.

Click to expand...

Exactly why I am asking, I am afraid I am still educating myself. I have 5 ports on my single spool control valve: 2 work ports, in port, out port, and power beyond (which is currently blocked). In my mind, I have 2 options to plumb it in:

1. Pump -> spool valve in; spool valve out -> pressure side of Powr Trol.

2. Pump -> spool valve in; power beyond -> pressure side of Powr Trol; spool valve out -> where? (this is where I thought it may T into the return line)

It sounds like option 1 is what used to be done. I am afraid I am just generally ignorant when it comes to whether the PBY port is even necessary in this situation (sounds as if it is not). If I leave the PBY port blocked, it should just act as a normal open spool valve, if I understand correctly.

EDIT: When you say "A relief line will be required from the relief valve port on the new valve back to the hydraulic reservoir." where do you plumb it in to? Since the Powr Trol is the reservoir already, I am just confused as to where the relief valve output should be plumbed in to.

Use option 1. You may not need a relief line back to the reservoir. Some valves relieve the pressure oil to the "out" port. In this case, you don't need a separate relief line. If there's a port labeled "relief" or "sump" then you need a relief line.

Here are a couple of pictures of the valve on the 70.

Another one of the valve on the 70

Well, it has been done: I successfully added a spool valve to my 70D.



I used a Prince Hydraulics model 5100 with a power beyond port, a low-pressure relief valve installed at 1100 psi, and a 4-position lever with a float position. I had a machinist make me adapters for the high pressure line out from my pump and into the Powr-Trol, as well as an adapter for the Powr-Trol drain plug, and left side light mount.

It is plumbed as follows:
-Outlet from the pump goes to the IN port on the spool valve.
-Power Beyond from the spool valve is plumbed to the pressure side of the Powr Trol.
-OUT from the spool valve is plumbed to a machined adapter where the drain plug used to be (this is the only access to the reservoir except for the fill port).
-Work ports are plumbed to the cylinders.
-A hydraulic filter with bypass valve is plumbed in-line from the line running OUT on the spool valve to the reservoir.
-I changed nothing in the suction line.

After all my research, I felt this was the safest way to do it. The OUT port on the Prince series 5100 is only made to handle 500 psi max, so lifting a heavy 3-point implement may exceed that limit as it passes through the spool valve. The power beyond port solves that problem.

To mount the spool valve, I had the machinist make an adapter from the left light mount that is already there. I put a T in-line and mounted it to the top using galvanized steel pipe and fittings. Obviously once it gets warmer, I plan to clean it up aesthetically, but for now it does the job.

This all started because my 3 point and loader would not raise in the order I thought they should when plumbed to the side ports of the Powr Trol (3-point first, then loader). I replaced every seal and gasket on the rear end of the tractor (Powr-Trol, rockshaft housing, and PTO and housing), but it still wanted to try to raise both the 3-point and loader concurrently. It appears that the loads were balanced just enough that they both wanted to lift at the same time.

I am very happy with this solution as now I have two almost entirely separate controls. Although both will not raise at the exact same time (to be expected), I have completely separate control over the loader and 3 point now. I want to thank everyone for their help! It has been a learning experience, but I am more excited than ever to keep learning the ins and outs of the 70D.

I'm glad you got valve installed & operating to your satisfaction.

IMHO you went to unneeded extra trouble/expense to plumb the power beyond port because it's not required on low pressure/low flow hyd system such as a JD 70

(quoted from post at 03:41:36 03/28/15)
I'm glad you got valve installed & operating to your satisfaction.

IMHO you went to unneeded extra trouble/expense to plumb the power beyond port because it's not required on low pressure/low flow hyd system such as a JD 70

Click to expand...

You're right, as clearly the original valves did not have the power beyond port. It gives me added piece of mind and a low pressure line to put an in-line filter.