3rd Function on Mahindra 4350

[irsmun]

Ok, more third function questions. It seems that there needs to be a separate forum topic for this heading. There are hundreds of pages of threads about it and the questions are all relatively the same but with each tractor and need of function they are unique. I like most, fully understand how the hydraulic system works in general practice. I do not however have the confidence to select the valve type I need.

Here are my questions and issues. A kit which runs me $700-$900 gives me convenience but at a pretty high cost. I know I can do this myself and do a cleaner install than the guys at the dealership...because I REALLY care about the look of the installation.

I want to run a grapple...the standard reason for wanting the 3rd function it seems. I want true third function without compromising the flow speed of the system any more than necessary. I do understand from JJ that true third function will run wide open or off. So...

What valve type do I need? It looks like I am simply identifying the PB line from my loader valve and putting this one in the middle with my two control hoses running to the front of the loader.

Do I need a return line for this valve or will it use the return line from the existing PB on the 3 pt?

What are the effects on my 3 pt with this installation? No running it while I am operating 3rd function?

On limiting the 3rd function flow rate...What rate would you suggest to run the grab cylinder? And does the valve come with this adjustment or is this a separate component?

I want to do this project for several reasons. Cost, learning, and getting the job I want done the way I want.

Sorry my title is wrong. I have a dyslexic keyboard. I have the 4530.

 

[J_J]

Here is a valve you can use.

12 VDC 10 GPM OC DA SOLENOID VALVE

Here is the subplate.

1 STATION DO3 SUBPLATE OPEN CENTER

This valve setup can be installed after the loader valve and before the 3pt,

Ideally it would be installed close to the front of the tractor in series with the other valves. .

There is no relief for this valve, so it uses the loader relief.

The OUT port of the subplate feeds the next valve.

The solenoid valve will have no flow if the loader is using all the pump flow. The loader valve has priority.

However it can operate if the loader is only using half flow.

It needs 12 volts through a handle switch, and you can wire the switch for momentary operation.

Your 3pt will work normally with no voltage applied, and work somewhat different with the switch on. If you hold the switch down after the cyl is fully extended or retracted, the loader valve will go into relief.

So essentially the normal flow is interrupted for the time the switch is activated.

It is not a big problem as the 3pt is not normally used during loader work.

If you are considering using the 3rd function for a BH or other implement on the back, you need to consider the placement of the solenoid valve so it can be easily accessed.

The return/OUT line goes to the next valve.

You can adjust the rate of operation of the grapple by using a needle valve or a restrictor in the grapple cyl circuit.

You do need the PB adapter on the loader valve or obtain the flow from the hyd block if you have one.

 

[MtnViewRanch]

Double check your GPM flow, I know that I would use a higher GPM rated valve and subplate.

 

[J_J]

Brian,

I don't think most people will run their tractor at max rpm, and therefore, the rated GPM of that valve should be OK.

Probably between PTO rpm and max.

or

Try this one


http://baileynet.com/hydraulics/sol...age=ProductDetails&line=SV3E&baileyno=220-313

http://baileynet.com/hydraulics/sol...age=ProductDetails&line=SVM3&baileyno=220-500

 

[MtnViewRanch]

I agree that most people do not run a high throttle when they first purchase. But as they get familiar with their machine, a lot of the time the speeds go up. And a lot depends on what they are doing with those machines. The 4530 is a utility size tractor. If he does field work, the throttle work is going to be high. The fluid running through those # 6 fittings is going to heat up. If he just spends another $100 or so, he never has to worry.

Sort of like having a 200MPH car with 160MPH tires. Well they work most of the time without any problems, but if you need that little bit more, well it may very well end up bad,............. or not. Is it worth taking the chance? :confused3:

 

[irsmun]

Ok, I am all about having a little more than I need. I bought this tractor to work commercially. I plan on running it hard and often. The grapple is going to be used for small demolition work as well as picking things up.

I am still digesting what was said. A couple of questions...

JJ said I should install it close to the front. When you say "close to the front" do you mean of the tractor, or to the pump, or to the loader valve?

I need help identifying my PB line. There is no documentation to that level that came with the papers. There are three 1/2" lines going to the loader valve. I think I have identified the right one but I can't be sure. Here are some pics showing the lines and my mount option.



I think line 1 is the PB. I cannot tell of the other two which is pressure and which is return. I just don't know enough about hydraulics yet to use the clues of proximity. There is not writing on the valve either. There is another port that is sealed with a hex wrench plug. Is that something I can use?

 

[J_J]

It looks like you have 7 hoses, so you apparently have PB.

Can you remove the fitting from the side of the valve, the one with the 90 degree fitting and look inside the port for a hex screw?

The other way to tell where the PB flow/main flow is to loosen a fitting, and if it leaks with all levers in neutral, that is the PB port.

You can also follow the hose back to the remote or 3pt

All return hoses go to tank and may have tees in it.

 

[irsmun]

I'm going to try the "leak" method today. My assumption is that these are compression fittings so the will be no need to use Teflon or pipe dope to re-seal.

 

[irsmun]

So here I am now...learning. I didn't want to make any modifications until I had a better understanding of the system. After all, I don't want to pay someone to fix my mistakes. I spent about an hour removing plates and following and marking lines. Here is what I have:



This is the same picture as before but now with handy dandy color coded zip ties. I have drawn a rudimentary diagram. I did not show flow direction since I don't really know which is going where or if with double acting cylinders if the flow changes.

I could only see two lines leaving the pump. One went to the steering column and the split to the front wheel cylinders. No brainer on that one.

The second line (marked as blue and numbered 3) goes into the loader valve. So does that mean that is the pressure line from the pump?

From the loader valve there are two remaining hoses that are contenders for the PB line. The green line (#2) goes straight to the rear of the tractor. The orange line (#1) goes to an open/shut valve also located at the rear of the tractor. According to Mahindra this valve is there to keep a three point attachment from accidentally moving if you are going long distances with the implement up.

I did the leak test on the #1 orange line as instructed. With the tractor running and the loader on the ground I loosened the fitting. Almost immediately fluid was being pushed out.

 

[J_J]

Number three is the INPUT from the pump as the relief valve is just above it.

You can also verify which line is the OUT/return by loosen or remove the hose from that port.

With PB installed, the internal valve chambers are divided so the main flow, flows on to the next valve.

The OUT port will only have fluid flowing when a cyl is being used. No cyl movement, no flow.

All OUT flows from a valve should be open to tank with no restriction.

The descent knob is use to set the 3pt lowering rate and to keep the 3pt secure for transport .

One other way to positively check the main hyd flow via the PB adapter is to install a tee and a 3000 psi gage in the PB line..

If that is the PB line, when you raise the 3pt to relief pressure, the gage will read that pressure.