Hydraulic expert wanted!

[3238dpw]

I bought my PT425 with an aeravator from First Products. Both are used. The attachment calls for 1800 PSI and 8 GPM. The PT has 2500 PSI and 8 GPM. I was assured by Power Trac that it could handle this unit when I told them the needed psi and gpm. I also called First Products and they said that the PT could drive this attachment. First products claims this unit uses half the power of a similar sized rototiller. I invested in an attachment plate and got it welded on, as the last owner didn't use the aeravator with the PT. Now it isn't working properly.

First, this is how it is supposed to work.
There are clusters of spikes (you can see 4 of them in the picture) that roll on offset bearings on a powered shaft. The clusters roll weather or not the power is on. When the power is turned on, the shaft spins independant of the cluster and the offset bearings (kind of like a cam shaft) make the clusters wobble or vibrate, which fractures the soil.

Now the problem.
If I turn on the PTO with the unit in the ground it does not wobble, but it does pull down the engine some. If I turn it on with it raised the shaft spins and the clusters turn also as there is no resistance.

In a nut shell if it is in the ground and there is resistance, it does nothing. When it is out of the ground and little to no resistance it spins. If there is some sort of restriction it seems to me like it would stall the motor. I tried my rototiller and it seems to be working fine.

I also know this is hard to explain so if there are any questions ask away.

This puts me in a real bind as I am supposed to use this piece of equipment this next weekend at 3 customer's houses.

Here is a link to First Products.

Welcome to First Products

 

[MossRoad]

A couple of things come to mind. First, when it is in the ground and you turn the PTO on, do you hear the reliefs open up the same way you would hear if the roto tiller jammed?

If not, maybe the hydraulic fluid is slipping past the motor. Could the unit have its own reliefs that are being popped? Does the unit have a slip clutch that may be slipping?

 

[3238dpw]

Well I am not sure what it sounds like when the relief valves open. I don't think the unit has a relief valve. It has hoses that go directly to the hyd. motor, but of course i don't know for sure

 

[wallace]

Do you know what machine it was use on prior to you purchasing it?
Check the manf. for the correct size hose to attach to your tractor, if you hose is to large it won't allow preasure just flow.
You may be getting the flow but not the pressure.
Do you have access to a pressure guage?

Rick

 

[3238dpw]

The unit was used on a 1430, but like I said I was told this was a good fit. I will work on recomended hose size. No I don't have a guage. What does one cost? I should probably get one.

 

[J_J]

I bought my PT425 with an aeravator from First Products. Both are used. The attachment calls for 1800 PSI and 8 GPM. The PT has 2500 PSI and 8 GPM. I was assured by Power Trac that it could handle this unit when I told them the needed psi and gpm. I also called First Products and they said that the PT could drive this attachment. First products claims this unit uses half the power of a similar sized rototiller. I invested in an attachment plate and got it welded on, as the last owner didn't use the aeravator with the PT. Now it isn't working properly.

First, this is how it is supposed to work.
There are clusters of spikes (you can see 4 of them in the picture) that roll on offset bearings on a powered shaft. The clusters roll weather or not the power is on. When the power is turned on, the shaft spins independent of the cluster and the offset bearings (kind of like a cam shaft) make the clusters wobble or vibrate, which fractures the soil.

Now the problem.
If I turn on the PTO with the unit in the ground it does not wobble, but it does pull down the engine some. If I turn it on with it raised the shaft spins and the clusters turn also as there is no resistance.

In a nut shell if it is in the ground and there is resistance, it does nothing. When it is out of the ground and little to no resistance it spins. If there is some sort of restriction it seems to me like it would stall the motor. I tried my rototiller and it seems to be working fine.

I also know this is hard to explain so if there are any questions ask away.

This puts me in a real bind as I am supposed to use this piece of equipment this next weekend at 3 customer's houses.

Here is a link to First Products.

Welcome to First Products

Your problem sounds like the one I had a while back with my flail mower. When I raised the flail mower, the blade drum turned at a good speed, but when I lowered it into the grass and weeds, it would slow down and stop. I didn't see any leaks, so I determined that the PTO pump was bypassing fluid. I had the pump checked and they also determined that it was bad. They tore it down, and showed me the problem. I purchased a new pump, but not from PT. It could be that that the motor on the aerator is worn out and bypassing fluid. The hydraulics people have a test unit that they put in line and can determined the GPM, and pressure. You can do the pressure test with a $15.00 gage. If you put a shut off valve after the gage on the pressure side, but before the motor, you can close the valve slowly, and note the pressure build up if the pump is good. Never close the valve all the way, or you will deadhead the pump and it will be damaged. It is also good to have a gage if you own an all hydraulic machine.

 

[J_J]

Do you know what machine it was use on prior to you purchasing it?
Check the manf. for the correct size hose to attach to your tractor, if you hose is to large it won't allow preasure just flow.
You may be getting the flow but not the pressure.
Do you have access to a pressure guage?

Rick

The size of the hose is not what determine the pressure, it is the resistance to the hydraulic flow. The size of the hose determines the amount of fluid that the hose can pass. The larger the hose, the less pressure that it can handle.

 

[3238dpw]

Thanks for the info everyone. I will have to look into a guage and shut off valve. JJ, if I take just the aeravator to a hydro shop, could they test it without my PT or should I take both? It is a lot easier to put the unit in the back of the truck a just take that. The hydro shop is in a busy area and don't want to have to take the trailer.

 

[J_J]

Thanks for the info everyone. I will have to look into a guage and shut off valve. JJ, if I take just the aeravator to a hydro shop, could they test it without my PT or should I take both? It is a lot easier to put the unit in the back of the truck a just take that. The hydro shop is in a busy area and don't want to have to take the trailer.

I would just take the motor off the areavator and take it to the hydraulic shop. The test only takes about 15 min. If you know the motor capabilities, they will tell you the current operation parameters. They told me that my motor was not worth rebuilding. It all had to do with labor, parts and down time. If the motor checks out good, I would take the PT in and let them check the pump.

 

[3238dpw]

Good advice. Thanks JJ