Hydraulic problems Power Trac 1850

[wdchyd]

the best is to tear down the pump completely......assess the damage, look carefully at the mating parts on that rotating barrel (you'll see where the valve plate meets the barrel) those surfaces need to be not scored......

Look at the pistons.....the shoes on the end should not be flopping loose

Please take a bunch of closeup pix of more damage......

Those parts are avail but depends on just how much is needed to repair

Even after you rebuild or replace pump, the components connected to this pump need tearing down and rinsing (including the hyd motors), if not the debris that is floating around between the pump and motors WILL do more damage if not flushed out

It's entirely possible the hyd motor damage from the original repair was was the pump coming apart and throwing debris into the hyd motor

 

[wdchyd]

. WDCHYD , is this the overcenter contruction that can also make forward/back.View attachment 293015View attachment 293016View attachment 293017View attachment 293018

Yes..

 

[PowerT1850]

Did not look good when I shared the pump.(See attached). Wondering if anyone can tell if this pump works in conjunction with these wheel motors? I dont think I have original now, in front (not connected) Danfoss and rear Roller Stator. If I buy a new pump I want new wheel motors aswell. Also need a simple circuit to connect this right.


http://www.surpluscenter.com/item.asp
.86 CU.IN./ .20 Cu.IN. | Piston & Hydrostatic Pumps - Quadra Trading Corp

 

[wdchyd]

That doesn't look good, needing a new rotation group at the very minimum, pricing out a new pump may be wise


Was there any original pump ID number on your old pump......the new pump you have a link at Surplus Center looks like the rear aux pump has the wrong mount and a different gear pump (smaller)
Don't forget these pumps are put together using different displacements, mounts, shafts and ports......sometimes you'r just as well not getting from a place like Surplus Center cuz they offer "surplus" excesses from other companies that cannot sell them, that way the price is cheaper but the model codes are different

 

[J_J]

Look at the teeth on the pump to engine, you will need to match those splines. and diameter.

Your PTO pump on the back of the VSP pump may fit, and might not. If it has the same number of teeth and diameter, then just bolt the PTO pump on the new VSP pump.

As far as I can tell, my wheel motors are connected in a series/parrallel setup.

My hyd system is a closed loop hyd system. The same fluid just rotates through the wheel motors, and the charge pump replenish any loss through leakage from the wheel motors, and also flushes the hot fluid from the pump to the radiator and then tank. My wheel motors also have drain lines.

One side of the pump output call it #1, goes to a tee. Half the flow goes to the back and the other half goes to the front. The back hose goes to a wheel motor, and the output from that wheel motor goes to another wheel motor input, and from that motor goes back to the input of the VSP pump. The back half is parrallel with the front. The return from the second wheel motor in the series circuit returns to the pump. The return flow is coupled through a tee and sent back to pump.

In reverse mode, the flow is from #2 port, trough the wheel motors and back to pump , radiator , then tank.

When you select fwd, the fluid flows to turn the wheel motors in a fwd direction. When you select rev, the fluid flows in reverse through the wheel motors.

It appears that the 3000 psi is developed across two wheel motors in series.

There is a 10 micron suction filter on my charge pump.

Your system could be connected so the left rear and right front is powered in a series circuit.

I am not sure there is standard with all the Power-Tracs.

 

[J_J]

You could make up your own circuit, such as a parallel wheel motor setup, but in a parallel arrangement, if one wheel loses traction, most or all of the flow will go through the motor with the least resistance.

You need to know how much torque you need to move the machine at a certain speed with a load.

To go parallel, since the pump will produce about 3000 psi, all the wheel motors need to be able to handle the 3000 psi . Now you need a VSP pump that will provide the GPM for the speed you desire.

You could do the series parallel like mine, or a series parallel but using the left front and the right rear, so as to always have some traction.

 

[PowerT1850]

Thanks for all help! Is there any good literature that descripe building hydraulic system like this? What is the best way to clean the hoses? By compressed air and a small plastic tube? Can you give me links to useful pump and wheel motors. Even filter to suction side to protect the pump. The ID- plate is gone on my pump, can it be possible to get a new rotation center anyway for this Hydura pump?

 

[J_J]

Oilgear Hydura Hydraulic Piston Pump PVW w Solenoid | eBay

Oilgear Hydraulic Variable Displacement Pumps

Send a picture to these guys above and maybe they can put you on track for parts or a new pump.

Wheel motors.

http://www.surpluscenter.com/sort.asp?catname=hydraulic&keyword=HMWM

http://www.whitedriveproducts.com/productPages/CE.html

http://www.sauer-danfoss.com/Products/PistonPumpsandMotors/ClosedCircuitLowPowerPumps/index.htm

As far as cleaning out hoses and other valves and motors, I think I would add an inline high pressure filter in the wheel motor circuit at the pumps input hose and use fresh fluid to circulate through the filter.

The charge pump on my VSP has a 10 micron suction filter , but that only filters make up fluid for the closed loop hyd circuit. The fluid coming into the suction filter is coming from the tank.

If you can find a small oil gear pump, you can make yourself a filter cart with two filters, a 10 micron and a 1 micron filter with gages, and a timer. Plug it into your tank and let it run as much as you need, checking the filters often .

You could run a lint free cleaning ball through all the hoses if you really want to get into large scale cleaning.

You might as well do a through job of checking all the hoses for cracking flaking, and general deterioration.

 

[wdchyd]

I use a solvent based cleaning tank w/air to clean hoses while off the machine......looking carefully you'll probably need more parts than just a rotation group to renew the pump (swash plate, valve plate, bearings ect)

Any way you can get the factory people to come up with a model code..??......with that you can figure out what the displacement is and possibly change it over to a different brand if parts not avail

That link on the Tennant sweeper may be helpfull as far as an exploded breakdown sheet but not for part numbers (cuz they may be from a different size pump)

 

[J_J]

Using a 45 HP diesel running at 2500 rpm.

A rough guess is that you have so much HP to turn all the pump you have, If you know the displacement for the other pumps, each one takes so much HP, so you can figure the HP to power the two pumps you know, and the remainder of the HP you can use to figure the VSP displacement.

If these two displacements are known

? Steering pump is a 3 GPM, .3 cu in displacement, at 3000 psi = 6 HP

? PTO pump 8 GPM, at .7 cu in at 3000 psi = 16 HP

Estimated HP available for VSP pump

VSP ------11 GPM-----1.0 cu in -------------= 23 HP

So if the engine was a 45 HP and the other pumps use about 22 HP, then the VSP would use the other 23 HP for drive.

This is a possible maybe scenario.