660 hydraulics

Arrived at the farm to do some mowing. No lift action. Looked
through the differential fill port. Oil streaming back from the
seam of the lift cover and auxiliary plate. O'ring(s) the likely
culprit?

(quoted from post at 23:26:43 04/27/14) Arrived at the farm to do some mowing. No lift action. Looked
through the differential fill port. Oil streaming back from the
seam of the lift cover and auxiliary plate. O'ring(s) the likely
culprit?

Click to expand...

Looked
through the differential fill port. Oil streaming back from the
seam of the lift cover and auxiliary plate."
Don't understand, as first sentence would imply leak is under lift cover & inside hyd cavity, but second sentence would be an external or on top of lift cover leak????

Duh, see what you mean Jesse. This is internal. Looking at the manual, it appears to be coming through the seam between the cylinder housing where the safety valve is located and the lift cover. I think this may be the same thing I just dealt with 6 months ago but not "spraying" this time as it was then.

(quoted from post at 07:12:18 04/28/14) Duh, see what you mean Jesse. This is internal. Looking at the manual, it appears to be coming through the seam between the cylinder housing where the safety valve is located and the lift cover. I think this may be the same thing I just dealt with 6 months ago but not "spraying" this time as it was then.

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hat ram cylinder safety valve under the accessory plate/down in the big hole is shown in the I&T manual to dump into the exhaust tube along with the back pressure via unloader valve, BUT those dump paths, unlike all the other connections between the ram/valve body casting & lift cover, have no sealing such as O-ring or gasket, so it seems free to leak to me & I guess it wouldn't matter as it dumps back into bottom of hyd cavity any way. I might expect your "leak" to be from back pressure/unloader when in unloading )hold or lower, but not lift) or from ram cyl safety during attempted lift if it is stuck open.

Jesse, you may recall I just replaced the cylinder safety valve
last Fall. Should the safety valve even open if there is not a
problem causing excessive pressure? The source looks to be
from the same spot as last fall though it was shooting out
probably because I had a bush hog attached when trying to lift.

(quoted from post at 21:56:59 04/28/14) Jesse, you may recall I just replaced the cylinder safety valve
last Fall. Should the safety valve even open if there is not a
problem causing excessive pressure? The source looks to be
from the same spot as last fall though it was shooting out
probably because I had a bush hog attached when trying to lift.

Click to expand...

o it should not open. It is only one of 3 sources that potentially dump back through the same un-gasketed path.

(quoted from post at 03:01:14 04/29/14)

(quoted from post at 21:56:59 04/28/14) Jesse, you may recall I just replaced the cylinder safety valve
last Fall. Should the safety valve even open if there is not a
problem causing excessive pressure? The source looks to be
from the same spot as last fall though it was shooting out
probably because I had a bush hog attached when trying to lift.

Click to expand...

o it should not open. It is only one of 3 sources that potentially dump back through the same un-gasketed path.

Click to expand...

Since I replaced the safety valve last August and will do so again now, and hope it solves the problem, is there anything I should do to troubleshoot the cause of pressure build up? Seems if these safety valves can fail by staying open they could fail by not opening. Then what happens?

(quoted from post at 07:08:55 04/29/14)

(quoted from post at 03:01:14 04/29/14)

(quoted from post at 21:56:59 04/28/14) Jesse, you may recall I just replaced the cylinder safety valve
last Fall. Should the safety valve even open if there is not a
problem causing excessive pressure? The source looks to be
from the same spot as last fall though it was shooting out
probably because I had a bush hog attached when trying to lift.

Click to expand...

o it should not open. It is only one of 3 sources that potentially dump back through the same un-gasketed path.

Click to expand...

Since I replaced the safety valve last August and will do so again now, and hope it solves the problem, is there anything I should do to troubleshoot the cause of pressure build up? Seems if these safety valves can fail by staying open they could fail by not opening. Then what happens?

Click to expand...

he ram cylinder safety valve in question is there to relieve excess pressure that occurs when the operator has a heavy disk or such lifted & runs too fast across furrowed ground, resulting in shock loading & high pressures caused by the bouncing of disk on 3 point. Zane speaks of the cylinder being ruptured on N tractor by this. This valve opening pressure is 2700 PSI, well above the 2000 PSI normal operating system pressure. A tractor could go a lifetime & never crack this valve. Once opened, it may trap trash on closing & leak. It should be very easy to verify such by removing & applying compressed air & feel/listen for a leak through the valve. If it leaks at 100-150 PSI, it has a problem. If mine, I would apply air pressure at test port on top of accessory plate & see if lift arms rise AND look and listen for leaks at this time. Under these conditions there is very little of the system exposed to pressure.......a few o-rings lift cover to acc plate & same to ram cylinder, the ram cyl safety valve, the check valve, control valve dump path and the ram cyl itself. If all OK, move forward with other checks. If not, you will have isolated the leak or at the very least isolated the search area.

My accessory plate has a valve built into it. Will that affect access to the test port?

(quoted from post at 16:58:11 04/29/14)
My accessory plate has a valve built into it. Will that affect access to the test port?

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ny 'accessory plate' that isn't the simple factory plate is wide open for what it is, so just set that valve to whatever position you would use when you want to use the 3 point and try it or send me information/picture of it.

It will be a week from Saturday before I get back to it. I'll probably take the compressor and replace the safety valve again hoping that's the fix and try the air test if not. I'll message you a photo of the auxiliary plate if necessary. Thanks.

(quoted from post at 22:18:10 04/29/14)
It will be a week from Saturday before I get back to it. I'll probably take the compressor and replace the safety valve again hoping that's the fix and try the air test if not. I'll message you a photo of the auxiliary plate if necessary. Thanks.

Click to expand...

ure. Like to see it.