Where to place a pressure guage

[woodlandfarms]

OK, New thread cause this has come up a few times.

I have the 1850. Used... New engine, rebuilt tram pump... JJ and others have suggested a Pressure guage for basic maintenance. So where and how would you put one on my PT, let alone any PT?

Now, on my PT there is a guage with the slope brake. I have never paid any attention to it, I assume it does not reflect the PT's pressure but just that of the braking system.

Love to hear some ideas on this.

Carl

 

[J_J]

OK, New thread cause this has come up a few times.

I have the 1850. Used... New engine, rebuilt tram pump... JJ and others have suggested a Pressure guage for basic maintenance. So where and how would you put one on my PT, let alone any PT?

Now, on my PT there is a guage with the slope brake. I have never paid any attention to it, I assume it does not reflect the PT's pressure but just that of the braking system.

Love to hear some ideas on this.

Carl

Carl, Gages are cheap enough so that you could put three of them in your system to monitor hydraulic pressure. If you don't want to put three, just tee in a tee fitting to accept the one gage. I have the small disconnects on my check points. Where are the check points? You have three circuits in the system. Tram and motor circuits. steering and lift circuits, and the PTO. On the tram pump, install a tee fitting at the pump outlet fitting and cap it off. This one will check the pressure at the tram pump. Steering and lift is on the same circuit. So up front on the input to the joystick valve, install a tee fitting and cap it off. This one will check lifting and tilt pressure For the PTO circuit, add a tee fitting to the pressure side before the quick disconnect on the front of the machine.. This one will check the PTO pressure when running a motor up front.

If you choose to install a tee with a female quick disconnect, any time that you want to check the pressure, plug in the gage with a male side of the standard quick disconnect, with the machine off. If you use the flat face couplers, they can connect under pressure. I leave my gage plug into one of the check points.

 

[woodlandfarms]

Always fantastic info. Got any pictures you can show? Do these guages show proper pressure when at idle or "in nuetral" or do they have to be observed at speed? I guess monitoring the tram pump would require me strapping the wife to the engine cowl.. Sometimes not a bad idea...

Also, any recommendations on guage providers and types? Sorry, just a real novice on hydraulics and need a bit of spoon feeding...

Carl

 

[Bob999]

Now, on my PT there is a guage with the slope brake. I have never paid any attention to it, I assume it does not reflect the PT's pressure but just that of the braking system.

My understanding is that the pressure guage on the brake tender reflects the maximum pressure developed by the variable displacement pump. My understanding is based on the PT drawings that show the source of pressure is the variable displacement pump, that the maximum pressure I see on my machine is about 2000 psi, and the pressure tends to remain at about 2000 psi even when the treadle is in neutral and engine speed is low. This pressure releases the spring acuated brakes and keeps them released so long as there is pressure in the drive system.

 

[J_J]

My understanding is that the pressure guage on the brake tender reflects the maximum pressure developed by the variable displacement pump. My understanding is based on the PT drawings that show the source of pressure is the variable displacement pump, that the maximum pressure I see on my machine is about 2000 psi, and the pressure tends to remain at about 2000 psi even when the treadle is in neutral and engine speed is low. This pressure releases the spring acuated brakes and keeps them released so long as there is pressure in the drive system.

I am thinking that you are seeing the pressure from the hydraulic accumulator, and it may have a check valve to keep it primed. The tram system is supposed to be a closed loop system. When you turn the engine off, do you still read any pressure? Is the brake tender applied automatically, or do you have to manually activate a handle, and do you see any pressure droop on the gage?

 

[J_J]

Always fantastic info. Got any pictures you can show? Do these guages show proper pressure when at idle or "in nuetral" or do they have to be observed at speed? I guess monitoring the tram pump would require me strapping the wife to the engine cowl.. Sometimes not a bad idea...

Also, any recommendations on guage providers and types? Sorry, just a real novice on hydraulics and need a bit of spoon feeding...

Carl

The proper hydraulic gage will be liquid filled to help keep the vibration down. The gages will show what ever pressure is in the system. Even if the pumps are running, and you are not doing any work, you will see very little pressure. A smart move you could do is to set up a three gage manifold on the dash so you can observe the pressure in your system. Two of the hook up points are up front, the third is on the tram pump, and you could run a 1/4 hyd line through the tunnel to the third gage, and then you can observe the pressure while you are moving.

As you know, in a hydraulic system, you can push fluid around quite easily. You will only see pressure when there is resistance to the fluid being pushed.
For example, if you had the gages on the lift cylinders, and you had a thousand lb load on the forks. the gages would read 0 pressure. Why, if the joysticks are not in use, the fluid is sent through the valve and back to tank. Watch the gage as you pull back on the joystick to lift the load, the pressure will build up close to the designed pressure, and the load will raise.. If you drop the load a few inches and stop suddenly, you will see the pressure spike higher, and then stabilize.

Most of the stuff I am telling here is just good old common sense.

 

[woodlandfarms]

I am thinking that you are seeing the pressure from the hydraulic accumulator, and it may have a check valve to keep it primed. The tram system is supposed to be a closed loop system. When you turn the engine off, do you still read any pressure? Is the brake tender applied automatically, or do you have to manually activate a handle, and do you see any pressure droop on the gage?

The guage drops to zero when the engine is off... And quickly...

 

[Bob999]

I am thinking that you are seeing the pressure from the hydraulic accumulator, and it may have a check valve to keep it primed. The tram system is supposed to be a closed loop system. When you turn the engine off, do you still read any pressure? Is the brake tender applied automatically, or do you have to manually activate a handle, and do you see any pressure droop on the gage?

I think that you are correct--the accumulator retains pressure.

When the engine is shut off the pressure immediately drops to zero. The pressure also goes to zero if the brake handle is moved from the operating position to the stop position.

When starting the engine the pressure remains at zero (and the brakes are applied) until the brake lever is moved to the operating position