Hydraulic problems Power Trac 1850

PowerT1850 · Dec 21, 2012

It is a Kubota V1200 and when I seach for this it seems that itｴs between 22,5-28 hp. What can you recommend:
PTO? VSP? Wheel motors ( with drain hose or not)? This is very useful for me though I must buy new parts. I have tried with more mail to Terry, but no answer.

J_J · Dec 21, 2012

This data suggest the HP is about 30 HP.

V-1200

M-35 75.5 cu in 30 hp @ 3,200 rpm

If that is true, then there are PT owners on the forum that have 1430 PT's and the might know the size of the VSP pump and the other pump displacements.

Is there any way for you to determine if that engine is the original engine.

What ever you do, the engine can supply so many HP, and that has to be divided between the VSP, the PTO, and the steering and lift.

PowerT1850 · Dec 22, 2012

Yes, The Kubota seems to be the original engine. http://www.tractorbynet.com/forums/power-trac/213825-pt-selling-used-1850-72-a.html
But it says it is a 1989 420, but when I spoke to Terry he says it is a PT 1850 I have. What is right? I would be nice to get a contact to an owner of this.

J_J · Dec 22, 2012

Another PT for sale.

Power Trac PT1430 4x4 Diesel Compact Wheel Loader Snow Blade Mower Low Cost SHIP | eBay

J_J · Dec 22, 2012

PowerT1850 said:
Yes, The Kubota seems to be the original engine. http://www.tractorbynet.com/forums/power-trac/213825-pt-selling-used-1850-72-a.html
But it says it is a 1989 420, but when I spoke to Terry he says it is a PT 1850 I have. What is right? I would be nice to get a contact to an owner of this.

The current 1850 are 65 HP, and if the V-1200 Kubota is only about 30 HP, then all the pumps and wheel motors will be different.

Your machine might be older than my 1445 which has a 45 HP FORD Industrial gas engine. The people at Power-Trac should be able to provide you with a parts manual.

If you have talked to Terry, he should be able to email you everything they have.

They sent me a parts breakdown of my VSP pump, which is made by Eaton.

PowerT1850 · Dec 27, 2012

A VSP pump that gives 6 GPM at 1800 rpm, does this give 12 GPM at 3600 rpm? What wheel motors for a PT1845 - PT1850? Is aprox.4500 in-lbs and 160 rpm ok? Open circut or close? What advantages disadvantages? What is enough for lifting and tilt GPM and PSI. How does displacement effect parallel / Serie couple? Many questions!!! Sorry but I must seek answered before I can go further.

J_J · Dec 27, 2012

Can you verify the diesel engine HP ?

Look at this chart at the M-35 which is Kubota v-1200, it is a 30 HP engine.

So based on that, I don't know why Terry is telling you it is an 1850.

If it is a 30 HP diesel, then all the 1430 hyd should work in your machine if you can find a pump adapter to match up to the Kubota engine.

There is a list of PT owners on this forum, and some of them have PT-1430's.

You might send each of them a PM requesting any data they can give you relating to pump and wheel motors and hose layout from pump to the wheel motors, and back to pump. . .

I think we all are willing to help, but you need to come back with certain data we ask for.

Look at the wheel motor hoses and determine how they are connected, draw a schematic of the hoses and wheel motors and pump configuration. Then we perhaps can provide more data.

The wheel motors and pump are configured for closed loop operation, whereby the fluid is circulated through the pump and wheel motors. Any fluid that bypasses the wheel motors goes out the case drains and to pump case drain, and then to radiator, then to tank.

My VSP also has a charge pump that provides any makeup fluid that was bypassed. All this fluid comes through a suction filter at the charge pump. Hydrostatic transmission need very clean fluid.

Logic would imply that a pump that can pump 6 GPM at 1800 rpm, can pump 12 GPM at 3600 rpm.

J_J · Dec 28, 2012

PowerT1850 said:
A VSP pump that gives 6 GPM at 1800 rpm, does this give 12 GPM at 3600 rpm? What wheel motors for a PT1845 - PT1850? Is aprox.4500 in-lbs and 160 rpm ok? Open circut or close? What advantages disadvantages? What is enough for lifting and tilt GPM and PSI. How does displacement effect parallel / Serie couple? Many questions!!! Sorry but I must seek answered before I can go further.

Pump displacement will determine the GPM given a certain engine rpm.

Your pump and motor probably a closed loop setup.

Motor displacement will give a certain rpm given certain GPM's.

If you flow 12 GPM through two 18 cu in motors at 3000 psi, in parallel, the GPM is divided between the two motors, each motor will get 6 GPM , and the rpm will be 77 rpm.

Possible scenario.

If VSP pump is 12 GPM at 3000 psi: 26 in diameter tires

Two 18 cu in, 1500 psi motors in series, 77 rpm , torque = 4299 in lbs, each.

Front two motors are in series.

Back two motors are in series,

Front and back are parrallel to the pump, one input and one output, so 6 GPM goes to the front, and 6 GPM goes to the back.

MPH will = 6

Torque = 1433 ft lbs

J_J · Dec 29, 2012

PowerT1850 said:
Hi, Thanks for help all of you. wdchyd is right it is Hydura I now find an exact same at Surplus center : .86 CU.IN./ .20 Cu.IN. | Piston & Hydrostatic Pumps - Quadra Trading Corp . this will make it a little easier I guess. I hope I can find the assembly drawing somewhere. My forward / back is controlled by solenoids, but the speed is manual lever from the pump. The Hydura pump at Surplus center is it used? Some warranty? You think.
PowerT 1850

Based on the displacement, the GPM's would be about 9 GPM, at 3000 psi, using about 18 HP from the engine

Do you know what the pump on the side of the engine attached to the flywheel is used for.

One of the gear pumps is for the PTO, and the other gear pump is for steering and lift.

J_J · Jan 1, 2013

Do you know you can use the fluid in a gear pump to determine the cu in capacity?

Drain all fluid from the pump, and then fill it full. Then turn one revolution and measure what comes out, and then convert the oz's to cu in .

For instance when you turn the pump one revolution and get 3 oz's, that will compute to a 5.414 cu in pump.

Capacity and Volume Conversion

Select fluid oz on left , and cu in on right side

Insert a number. You have your answer.

PowerT1850 · Jan 3, 2013

I will check how all is connected and come back. My pump, side of engine is for steering. I have no radiator for cooling, maybe it is an open circuit?

PowerT1850 · Jan 16, 2013

Hi, I called Terry, and he could not help me to get a pump for my 1430. I got a circuit (open) for a similar newer from him, but it would be nice if someone could give me the right circuit ( late 80s) . I have an idea aboute the pump replacement. To use this: Surplus Center - PRINCE DOUBLE PUMP CW KEYED (CUSTOM) , and use a valve that direct from pumping around and gradually out in circuit with my hydraulic pedal. I have the frontward/backwards electrical. Must there be an expensive axial piston pump or is this cheaper solution with gear pump possible?

J_J · Jan 16, 2013

I think you would be better off getting something like this and adapting it to the engine if the coupling is not correct.

[Surplus Center - 2.30 cu in VARIABLE TANDEM PISTON HYD PUMP DANFOSS

since you only have a 15 GPM pump total capacity to work with, I selected these displacements if you are going with a gear pump

,Burden Surplus Center

Since the HP on the Kubota is about 30, you only have HP for about 15 GPM, and that includes all three pumps,

Drive/VSP

PTO

Steering and Lift

Did Terry happen to say what the displacement on the VSP pump was?

SpringHollow · Jan 16, 2013

JJ, that is a 50 GPM pump!

J_J · Jan 16, 2013

I know, I changed it to a smaller one, but even that is to big.

I tried to compute the displacement for the double gear pump and posted.

He has to stay with in the 15 GPM total at 3000 psi

I don't know if Terry is giving him his best shot, as the pump from the 1430 should be close, which has a 30 HP diesel.

Matching the splines to the Kubota engine might be difficult.

PowerT1850 · Jan 17, 2013

No, Terry could not help me more. No documentation from that time. Does it work ok with gearpump and control like my suggestions? Is it some drawback with gearpump? My pump have 3/4 inch axel and with parallel key. Is 14-15 cu in with 150-300 rpm for wheel motors ok?

J_J · Jan 17, 2013

There are some things that are not correlating. The label on the engine says it is a V-1200, and the HP is about 30 HP.

You say you have a 14 cu in pump, but you don't have the HP to run that pump.

A 6.0 cu in pump turning at 2500 rpm would pump 65 GPM.

To pump 65 GPM's at 2500 psi would require about 111 HP.

A gear pump would pump the fluid, but controlling the flow to the motors might be a little difficulty.

You will need larger hoses, larger filters, large GPM type valve, large fittings,etc.

You will need flow control for hyd motor speed and a way to switch the flow.

I would ask Terry why you can not use a 1430 VSP pump.

If someone on the forum has a 1430, they might be able to tell you the cu in displacement.

Running all the pumps, you only have 30 HP.

Several manufacturers make the VSP pumps, Eaton, Sauer-Danfoss, Sunstrand.

This type valve will control the speed of the motors in one direction .

This is the type valve I have on my 1445 for the PTO.

http://www.surpluscenter.com/item.asp?item=9-064-50&catname=hydraulic

PowerT1850 · Jan 18, 2013

I mean the wheel motors should have 14-15 cu inc. What is the size of wheel motors for a PT 1445 with 45 hp?
Questions for a 1430:
1. Pump for wheel motors, flow and pressure and rpm.

2. Wheel motors cu inc, rpm.

3. Pump for lift and tilt, flow, pressure and rpm.

SpringHollow · Jan 18, 2013

A local hydraulic shop might be able to identify and replace/repair the existing pump.

Ken

PowerT1850 · Jan 18, 2013

I have tried, but with no id plate and ( in Sweden rare) /old Hydura pump with all the piston shoes in very ,very small pieces.Se earlier in this thread...