TYM T330 HST Joystick Control Leak

[K5lwq]

Great pictures! I edited one to mark the the lines.

 

[oldnslo]

Harry I read that page - so this would go on the inlet side of the loader control valve, and would require a new hose that would go from the power return sleeve back to the reservoir? Is that correct?

Edit: It's starting to make sense I think. So when I raised the 3PH with the heavy snowblower, there was a large demand on the system, so the pump increased flow. This increased flow also went to the loader valve since it's connected to the same system. Hence the fluid gushing out when the 3PH was raised.

A Power return sleeve would be a gatekeeper for that extra flow and send it back to the reservoir. Correct?

Matt
You have the concept right with exception of when raising the 3 point the load requires increased pressure which is acting on the tank port of your loader valve and blowing the seals. Not to scare you but I would recommend not using the 3 point under load until you get the plumbing issue resolved. Reason for this suggestion is that excessive tank pressure can crack the loader valve casting.

 

[MoMatt]

Matt
You have the concept right with exception of when raising the 3 point the load requires increased pressure which is acting on the tank port of your loader valve and blowing the seals. Not to scare you but I would recommend not using the 3 point under load until you get the plumbing issue resolved. Reason for this suggestion is that excessive tank pressure can crack the loader valve casting.

OK - good to know. I've used it the way it is for about 4 years now, and the tractor came with the property so the previous owner used it as is before that, so if nothing else it's built tough.

I had the thought to check the owner's manual, this should be helpful:

Look closely around the ports. You should see P for power in, T for tank and C or Y for power beyond. The C would be where the power beyond sleeve would go so this one likely has a plug now.

I'm going to spell it out for my benefit because I'm slow.

• P is from the PTO valve (in series I presume) - "power in" meaning the pressure side / supply
• T is the tank return (after it goes through the loader valve). From the picture, what is the TPL?
• P1 goes to the transmission housing (???) I'm looking at the service manual schematic Fig. 9-1 and it doesn't include the transmission in the schematic - is this the equivalent of C or Y

Edit: Looking at my picture of the stainless lines, there's a line hooked up to P and a line hooked up to P1. T is capped. This is a hydrostatic transmission - does the flow go:

Tank - PTO Valve - Loader - Transmission - Tank?

 

[Harry in Ky]

Harry I read that page - so this would go on the inlet side of the loader control valve, and would require a new hose that would go from the power return sleeve back to the reservoir? Is that correct?

Edit: It's starting to make sense I think. So when I raised the 3PH with the heavy snowblower, there was a large demand on the system, so the pump increased flow. This increased flow also went to the loader valve since it's connected to the same system. Hence the fluid gushing out when the 3PH was raised.

A Power return sleeve would be a gatekeeper for that extra flow and send it back to the reservoir. Correct?

Markings on the loader valve may be confusing. USUALLY the pressure "in" port will be labeled P, and will be closest to the relief valve. The exit ports will be on the opposite side. Depending on the design of the valve casting there may be as many as three ports. This gives more options for mounting and plumbing the valve in close quarters. The unused ports will have plugs screwed in. The sump return port will probably be labeled T. There may be more than one of those, but there will be only one power beyond port. Lately I've seen that one labeled N on Eastern European valves. With that port open, looking inside you will see an open space then a machined bore slightly beyond that. The power beyond sleeve will fit through the open space and seal around the inner machined bore. similar to drawing in the link I posted. That port, with sleeve installed, connects to the tractor's existing hydraulics, assuming the pressure line to the loader valve comes directly from the pump. If you can't figure out which line is which by tracing the lines, you can determine that with compressed air and a rubber tipped air nozzle if it comes down to it. I've done that many times.

 

[MoMatt]

Markings on the loader valve may be confusing. USUALLY the pressure "in" port will be labeled P, and will be closest to the relief valve. The exit ports will be on the opposite side. Depending on the design of the valve casting there may be as many as three ports. This gives more options for mounting and plumbing the valve in close quarters. The unused ports will have plugs screwed in. The sump return port will probably be labeled T. There may be more than one of those, but there will be only one power beyond port. Lately I've seen that one labeled N on Eastern European valves. With that port open, looking inside you will see an open space then a machined bore slightly beyond that. The power beyond sleeve will fit through the open space and seal around the inner machined bore. similar to drawing in the link I posted. That port, with sleeve installed, connects to the tractor's existing hydraulics, assuming the pressure line to the loader valve comes directly from the pump. If you can't figure out which line is which by tracing the lines, you can determine that with compressed air and a rubber tipped air nozzle if it comes down to it. I've done that many times.

OK, thanks Harry. That's a good explanation. I'm going to get in touch with the dealer and get this figured out.

 

[K5lwq]

OK - good to know. I've used it the way it is for about 4 years now, and the tractor came with the property so the previous owner used it as is before that, so if nothing else it's built tough.

I had the thought to check the owner's manual, this should be helpful:
View attachment 773049


I'm going to spell it out for my benefit because I'm slow.

• P is from the PTO valve (in series I presume) - "power in" meaning the pressure side / supply
• T is the tank return (after it goes through the loader valve). From the picture, what is the TPL?
• P1 goes to the transmission housing (???) I'm looking at the service manual schematic Fig. 9-1 and it doesn't include the transmission in the schematic - is this the equivalent of C or Y

Edit: Looking at my picture of the stainless lines, there's a line hooked up to P and a line hooked up to P1. T is capped. This is a hydrostatic transmission - does the flow go:

Tank - PTO Valve - Loader - Transmission - Tank?

P1 will go back to the valve for the 3pt hitch. This is where the power beyond line from the valve will go. Just need to find the sleeve and correct port. Different valve manufacturers mark the valve different. C stands for Carry Over, Y stands for Power Beyond, and N stands for Next. Thank you Harry for pointing that out.

You finding that in the manual clears it up for me. Unfortunately they did not put it in the service manual. But I like the way they provided a easy way of adding a valve. Hard to believe a dealer installed this valve. I bet TYM provided the power beyond sleeve and the dealer did not know where it goes.

Maybe get pictures of the valve markings and we might be able to identify the manufacturer for you. Sometimes there will be a tag with a model number on the valve. That will help locating a power beyond sleeve if the dealer can’t help.

 

[LD1]

Late to the party buy you are on the right track. I'll try my hand at explaining some things.

First, your current valve......its open center. And when the loader is NOT being used, hydraulic oil comes from the pump, enters the valve at the P port, and exits the valve at the T port.

Where the fluid then goes, out the T port and on to what you are calling the "transmission". Well, inside that transmission sump is the workings for the 3PH. So its actually supplying the fluid to operate that.

Lifting a fairly heavy blower may require some significant pressure. This pressure is what others are referring to as backpressure on the T port of the loader valve.

Now lets shift gears here.....you decide you want to operate the loader. The oil coming out of the pump and in the P port of the loader no longer just passes through the loader valve and out the T port. Instead, it is directed to one of the loader cylinders to extend whatever cylinder you are trying to move. And by doing so, the fluid needs to be expelled out of the other end of the cylinder and back through the loader valve and exit the T port.

But wait, the T port has excessive back pressure because of the blower hanging on the 3PH.....instead of an easy path to return to the sump/tank.

This is why your loader is having issues, unless you set the blower on the ground and relieve that backpressure issue.
And this excessive backpressure is indeed why you are blowing out the loader spool seals, because the tank passages are designed for minimal pressure.

Now enter power beyond into the mix:

The way it is supposed to work is you still have ONE pressure inlet to the loader valve. But you are giving the fluid TWO pathes to exit the loader valve.

Path 1 is PB. This is where fluid goes when NOT using the loader. Hence "power beyond". Because its to power something "beyond" the loader valve such as the 3PH. And can do so at full system pressure.

Path 2 is the T port. OR a free path back to the tank. When you activate the loader control to move the loader.....fluid no longer goes out power beyond, oil being expelled out of the loader cylinders as you either extend or retract them now exits the T port and simply dumps back to the tank and no longer has to fight the backpressure of the heavy blower hanging on the 3PH.

So you are on the right track getting with the dealer and tracking down a PB sleeve for your current loader valve. Find that sleeve and install it. The line you currently have coming out of the tank port of the loader and going to P1 on the tractor will hook to that sleeve and continue feeding the 3PH through that P1 port. Then you will add 1 hose going from a T port on the loader down to the capped T line that isnt being used.

 

[MoMatt]

Late to the party buy you are on the right track. I'll try my hand at explaining some things.

First, your current valve......its open center. And when the loader is NOT being used, hydraulic oil comes from the pump, enters the valve at the P port, and exits the valve at the T port.

Where the fluid then goes, out the T port and on to what you are calling the "transmission". Well, inside that transmission sump is the workings for the 3PH. So its actually supplying the fluid to operate that.

Lifting a fairly heavy blower may require some significant pressure. This pressure is what others are referring to as backpressure on the T port of the loader valve.

Now lets shift gears here.....you decide you want to operate the loader. The oil coming out of the pump and in the P port of the loader no longer just passes through the loader valve and out the T port. Instead, it is directed to one of the loader cylinders to extend whatever cylinder you are trying to move. And by doing so, the fluid needs to be expelled out of the other end of the cylinder and back through the loader valve and exit the T port.

But wait, the T port has excessive back pressure because of the blower hanging on the 3PH.....instead of an easy path to return to the sump/tank.

This is why your loader is having issues, unless you set the blower on the ground and relieve that backpressure issue.
And this excessive backpressure is indeed why you are blowing out the loader spool seals, because the tank passages are designed for minimal pressure.

Now enter power beyond into the mix:

The way it is supposed to work is you still have ONE pressure inlet to the loader valve. But you are giving the fluid TWO pathes to exit the loader valve.

Path 1 is PB. This is where fluid goes when NOT using the loader. Hence "power beyond". Because its to power something "beyond" the loader valve such as the 3PH. And can do so at full system pressure.

Path 2 is the T port. OR a free path back to the tank. When you activate the loader control to move the loader.....fluid no longer goes out power beyond, oil being expelled out of the loader cylinders as you either extend or retract them now exits the T port and simply dumps back to the tank and no longer has to fight the backpressure of the heavy blower hanging on the 3PH.

So you are on the right track getting with the dealer and tracking down a PB sleeve for your current loader valve. Find that sleeve and install it. The line you currently have coming out of the tank port of the loader and going to P1 on the tractor will hook to that sleeve and continue feeding the 3PH through that P1 port. Then you will add 1 hose going from a T port on the loader down to the capped T line that isnt being used.

Alright! I get it now. Makes complete sense on why I'm having the bucket issues.

Thanks again to all of you for spending the time to look at and think about this stuff. What a great resource.

 

[MoMatt]

Hard to believe a dealer installed this valve. I bet TYM provided the power beyond sleeve and the dealer did not know where it goes.

I suspect it's the same dealer (local tractor repair shop actually) that sold the previous owner an oversized snowblower. I was steered away from that shop by neighbors pretty early on.

 

[MoMatt]

I've got a couple more pictures and a video to try to see the markings on the valve - they didn't come out as well as I'd hoped. It's cold and the valve is dirty.

Here's a video that may make it easier to read:

As best I can tell, the brand ends in ...MCO and there are 4 horizontal lines at the front of the logo.

On the left (from the seat) of the loader valve there is a plugged port behind a port marked T2 (hose connected). On the right, there is just one port with a hose connected marked P2.

I couldn't make out any marks on the plugged port.