test your T273 rear remote PSI

[J_J]

You mean that when I stick my bucket under a rock and can't lift it or get the curl to lift it I'm not using the rams to their designed load?

Wouldn't the lift have a MA of less than one while the curl will have a MA of greater than one.

As stated in my earlier post, you only get max force from any cylinder at 90 degrees. Go to Surplus hydraulics, and select tech help, and then select cylinder force, and angle force. I think you can decide for your self, because it's true. The cylinders that we use could be made to work twice as hard, but it is not practical to use them at their best.

A 3 in cyl, 1.5 in shaft, at 3000 psi, can push 21,000 lbs, at 90 degrees

At 45 degrees, you can push 14,000 lbs

At 20 degrees, you can push 7000 lbs

At 0 degrees, you are pushing parallel to the cylinder , and you get 0 lbs

A lot of different cylinders if used correctly, will use their full potential.

 

[J_J]

myyaz33 ,

I apologize for the misstatement, because you were simply stating what the book said.

The pump on a tractor is rated for continuous pressure, and intermittent pressure. I believe the fluid flows to the FEL, and routed to the cylinders, and the pressure is regulated by a relief valve in the FEL valve, just for the cylinders, and returns back to tank. I could be wrong, but I think that the flow-through fluid that goes to another valve is not regulated and can have a different relief setting. Now, some attachments may be designed for a certain pressure, and could be higher that pump pressure. In this case, the relief setting on the BH, may not ever relieve, because it will never see the designed pressure. It may not also be working at full potential, because of lower pressure. Maybe the PS power steering has a 1500 psi cylinder on it, and therefore the pressure has to be regulated to say 1300 psi.

 

[Jerry/MT]

I agree with your statement that upstream pressure has to be higher but not sure what you mean by misstatement. I am only posting what is listed in the manual and trying to get clarification for the questions I posed in the original post. Basically, is the manual wrong or am I misreading?

1. What should be the pressure at the rear remotes?
2. What does "working pressure" at 1813psi mean in the tractor manual?

I have likely used some poor wording so, am going to try and clarify now that I have found the relief setting for the tractors hydrostatic pump. Here are some facts.

- Hydrostatic pump relief setting - 4978psi (according to Tractor Service Manual not Operators Manual pg.56)

- Hydrostatic Pump Pressue Test - Should be 1848~2417psi (according to Tractor Service Manual pg.70)

- Hydraulic "Working Pressure" - 1813psi (according to Tractor Operator Manual pg.90) What exactly is "working pressure"?

- LT200 Loader "Relief Setting" - 2300psi (according to LT200 Loader Manual pg.8) I have also verified the loader pressure at 2300 with my guage.

- BT200 Backhoe "Working Pressure" - 2466psi (according to BT200 Backhoe Manual pg.10)

System Feeds Like This
HydroPump>LoaderValve>RearRemoteValve

So first off, I am not sure I understand the terms "Working Pressure" and "Relief Setting" the way they are used in the manuals. But with my understanding and using the information in the manuals there is no way the backhoe should be able get to its working pressure (2466psi) as it is limited upstream by the loader valve relief set at 2300psi.

I'm not sure about the terminology either but I can take a stab at it.

Hydrostatic pump relief pressure is the max pressure that the pump can deliver deadheaded(i.e. zero flow). This is not a useful number since the relief settings wil not let it get there.

Hydrostatic Pump pressure test pressures are the range of pressures that the pump delivers with the working flow rates that it generally operates at.

Working pressure is a pressure that the pump delivers at some flow rate and I don't know that this is a useful number unless it can be tied to what is being worked.

Loader relief setting is obvious.

Backhoe working pressure is the pressure that the pump deivers at some flow rate when using the backhoe circuits. Not too useful unless the exact circuit is known.

As I said previously, I have seen other TYM spec numbers that do not look correct to me in other areas so it would not surprise me if other system numbers were erroneous. I guess the only way to really know what these pressures mean is to ask TYM or you local dealer's service tech.

 

[Bkjohns]

So, having adjusted to 2300 psi, do you notice any difference in performance?

 

[J_J]

One should be careful about adjusting the relief valves, especially with out knowing the max pump pressure, and that is only on a new pump. As a pump wears, the pressure generated may be lower than advertised due to wear, and fluid bypassing in the pump. The working pressure is the normal pressure/available pressure through the hydraulic circuits. In order to give more life expectation for the parts, the relief valve is set below the normal pressure. Most all pumps have a continuous , and an intermittent pressure. Every relief valve could be set differently, just to protect that part of the circuit.

 

[myyaz33]

So, having adjusted to 2300 psi, do you notice any difference in performance?

Absolutely, better performance overall.

 

[honorbound]

my relief setting was 1800 also at thr rear auxilary valve. After many phone calls about no digging power, my dealer was able to get info from TYM. He was told to increase the relief settind to 2300psi for the BH. I have not yet tested the fel to see what the pressure there is.