M930 Charging Valve-Bad oil leak

[PowerTracManiac]

Ok, first bad oil leak. This valve is bolted to the back of the port side wall inside the rear tub.
Noticed a line of oil on the dirt while driving and realized that can't be good.
Was able to locate the leaking area by where the oil was pumping out the side of this valve. A slow steady stream of oil about 2mm in diameter. (Caution-upon repair, I have found out that there is high pressure associated with this part/area/hoses)
There is a hydraulic line coming out the side of this valve (see photo below). The oil is clearly coming out of the body of the valve at the round area-not the hydraulic line or the fittings.
Anybody have to deal with this part before?
Don't have a service/technical manual. Only a parts manual.

 

[K5lwq]

That looks like a ORB type fitting. If you take the hose off and then the fitting, I believe you find a O-ring that is probably the source of your leak. A new O-ring and it should be good to go.

 

[PowerTracManiac]

TU for the tip about the o-ring.
Was able to find some more information about this part in the search feature. Does anyone have a schematic for the hydraulic systems on a PT1460?
I was noticing the regular chunking sound that Ponytug mentioned in a previous post prior to this valve leaking. It feels like a pulse/chunk at the steering wheel and when it pulses (or chunks) you can see the spring in this valve move slightly? Other than the leak in this valve and the chunking feel, the tractor seems to work OK?

 

[ponytug]

TU for the tip about the o-ring.
Was able to find some more information about this part in the search feature. Does anyone have a schematic for the hydraulic systems on a PT1460?
I was noticing the regular chunking sound that Ponytug mentioned in a previous post prior to this valve leaking. It feels like a pulse/chunk at the steering wheel and when it pulses (or chunks) you can see the spring in this valve move slightly? Other than the leak in this valve and the chunking feel, the tractor seems to work OK?

From your first post: on the M930 charging valve there is an o-ring under that fitting which probably broke. My bet is that if you fix that the above symptoms will all go away.

The chunking sound / spring movement is the charging valve alternately charging the brake circuit, kicking out to bypass the oil to the steering/FEL, and then kicking in (chunk) to repressure the brake circuit. I'm not at the tractor so I am not 100% certain whether it chunks on the in, or the out, movement, but you get the idea.

From your message above: Other than bleeding oil, and having steering that momentarily seizes, or an FEL that has minor movement glitches while under powered movement,
no,
the tractor should more or less function normally.

In normal operation, the M930 should cycle at startup when the pressure comes up and the brakes are turned off. After that, it should only cycle if you turn the brakes on, or if the engine dies. If it is cycling more frequently, you have a leak, probably in the the M930 itself, but possibly the brake circuit. As the M930 ages and wears, the valve itself will bypass oil internally, bleeding the brake circuit, causing the valve to cycle. When it becomes annoying, replace it.

FWIW: My only trick on replacing the M930 is to leave the 1"(3/4"?) adapter on the forward edge of the M930 on the M930 until the M930 is off the tractor, and then put the M930 in a vice with a socket on the adapter. I find that on the machine there isn't enough room for me to get the leverage and motion to remove it easily. I have had to use a breaker bar.

On the M930 valve: The hex screw on top of the M930 is a breather/bypass hole that weeps oil. You can get a kit from Power-Trac that routes that oil back to the tank. I installed the kit because I was tired of the dust that the oil attracted. For me, I think that dust on the spring accelerates the wear of the valve. Also, I believe that as the spring driven plunger cycles and wears out, the amount of oil leaking from the weep hole increases.

All the best,

Peter

 

[PowerTracManiac]

I have deliveries coming tomorrow and I need the machine to work NOW.
Just picked up the new charging valve assembly PT sent me. I also asked for one of those o-ring fittings and thankfully it was in the box with the new valve assembly.
Installed the new o-ring fitting into my old valve assembly and it is not leaking anymore. Ok, so I can use the tractor tomorrow-Thank God! However, it is still clunking every couple seconds. I guess that means I have to replace the entire valve assembly when I get a chance.
Hate taking those other fittings that are not leaking now off my old valve assembly and reusing them on the new assembly, but that is what PT said to do.
Now for the next issue to address. My old valve appears to be different from the new valve? Doesn't look like there is a place that will fit my accumulator? Also I have 2 ports on the bottom of the old and this has 1? Mine also doesn't have the red and blue ports on top that this one has? Do u still use the accumulator with the new valve?
New valve photo below:

Old valve below

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[ponytug]

I must be missing something, but I think that they look the same. (Edit: I don't see the second port on the bottom.) Six ports in the right places. They may have switched manufacturing sources for the valve. The small company that I think invented them went missing a few years back, and I assume went out of business.

The accumulator port is usually stamped "ACC", but not always visible after the heavy paint job.

All the best,

Peter

 

[PowerTracManiac]

Thnks for the clarification, but I have plugs where there are ports on this new one and vice versa?
Also, I believe that accumulator port hole is smaller than my old one. It is stamped B. Dont think this is plug and play for me.
I sent Terry a picture of my old one when I discussed this with him and he didn't mention anything about a kit for drainage or a new design. Looks like I will wait for PT to open to figure out what to do.
I sure am glad I asked for that fitting.
Really apreciate your help and sharing information.

 

[ponytug]

Did you ever get this sorted out?

All the best,

Peter

 

[PowerTracManiac]

I replaced one 90 degree fitting on the valve (which had a seal that was leaking) a few months ago and that resolved the issue.
Machine working good since then. Thank goodness cause I needed it to finish up stuff on my house project.