Hydraulic Motor Question

[Richard]

Good info, thank you!

Mine is actually a Terrain King brand, prior to them being bought by Alamo. If you looked at the Alamo Falcon 15, that would be the newer version of what I've got.

Called the Deere dealer yesterday to see if they can do.... manager wasn't sure and is going to ask the tech on Monday. There is a hydraulic shop 4-5 miles further but I don't know if they do the actual work there or take it to a larger shop they have 2-hours away.

I don't intend on using mower until this is figured out.

 

[Richard]

Just took them out. As it happens the two identical were on the wings and the different number was on center so that part was right.

I don't know how much this might matter. The very first O-ring has the little plastic "split washers" (don't really know what they're called) on BOTH sides of the O-ring. I don't know if this is to strengthen the hold of the O-ring or if maybe they actually hold some pressure. I have to believe since they are there, they have a purpose. The first washer, the innermost, the "first" one, was broken and maybe 10-15% of it was missing. It was not a full circle like the others. I was in the (dark) garage so wasn't sure if I saw a dent in the O-ring or not. I'll look later with a good light.

If these nicks DO matter....as it happens, they were on the right wing, the very one that's having issues.

So, fingers crossed that some dufas (er....me) might have buggered it up when installing AND fingers crossed that the hydraulic shop might be able to replace those.

Makes me wonder....when I installed them, I simply pulled old out, put new in. Should I have oiled them? (there was already fluid oozing from the threads when I pulled the old one out so I presumed that would lubricate them as they worked their way in. I'm now guessing that was a bad thought.

 

[rScotty]

Just took them out. As it happens the two identical were on the wings and the different number was on center so that part was right.

I don't know how much this might matter. The very first O-ring has the little plastic "split washers" (don't really know what they're called) on BOTH sides of the O-ring. I don't know if this is to strengthen the hold of the O-ring or if maybe they actually hold some pressure. I have to believe since they are there, they have a purpose. The first washer, the innermost, the "first" one, was broken and maybe 10-15% of it was missing. It was not a full circle like the others. I was in the (dark) garage so wasn't sure if I saw a dent in the O-ring or not. I'll look later with a good light.

If these nicks DO matter....as it happens, they were on the right wing, the very one that's having issues.

So, fingers crossed that some dufas (er....me) might have buggered it up when installing AND fingers crossed that the hydraulic shop might be able to replace those.

Makes me wonder....when I installed them, I simply pulled old out, put new in. Should I have oiled them? (there was already fluid oozing from the threads when I pulled the old one out so I presumed that would lubricate them as they worked their way in. I'm now guessing that was a bad thought.

Hard to say. O rings are different from any other type of washer - including flat rubber & plastic washers - because O rings are always compressed into a groove. The more pressure, the better they seal.

But machining a precise O ring groove costs manufacturing money, so back before O rings were popular a lot of machinery from the 50s and 60s and even later used "reinforced washers" where most desgners use O rings today. ....
these reinforced sealing washers were basically flat rubber washers bonded to a surrounding ring of metal or plastic. Is that what you are seeing? Parker and a few companies still make those reinforced washers. I think that McMaster carries them, too. But better be sure what your machine uses.

If the fitting is supposed to have an O ring it will always have a groove for the O ring to expand into and which supports the O ring against blow out. You can see that in the third picture below

I think you are OK on the oiling. Just some assemby oil is all it needs.
rScotty

 

[oldnslo]

Sounds like he has split teflon back ups on those relief valves. These are typically installed on the low pressure side of O-ring to help prevent O-ring extrusion. 1,500 PSI is about pressure limit for O-ring without a back up.

The this split teflon rings can get pinched on installation especially if they are protruding slightly.

 

[rScotty]

Sounds like he has split teflon back ups on those relief valves. These are typically installed on the low pressure side of O-ring to help prevent O-ring extrusion. 1,500 PSI is about pressure limit for O-ring without a back up.

The this split teflon rings can get pinched on installation especially if they are protruding slightly.

I'd agree. At least he has now found a possible culprit. "We have met the enemy and he is us"...or whatever that quote is.

Not many liked the bonded and crushable O rings - or any of the O ring wannabes with back up rings. Like I said, industry has mostly gone away from them. I've seen them more in instrumentation than in machinery.
If a person owns a machine that uses them, pay attention to the torque and consider that they are best if only used one time & replaced.

 

[Richard]

Sounds like he has split teflon back ups on those relief valves. These are typically installed on the low pressure side of O-ring to help prevent O-ring extrusion. 1,500 PSI is about pressure limit for O-ring without a back up.

The this split teflon rings can get pinched on installation especially if they are protruding slightly.

I'd say this appears to be my exact situation. Presuming the hydraulic shop (I'm now killing the idea of going to the Deere dealer) anyway, presuming they have these split teflons, I'm going to see if they'll check all of them.

 

[Richard]

others appear to be intact

 

[Richard]

Just so you know, it drives me batty when someone posts, disappears for five years (sarcastic) and then come back to continue so, my apologies for being that person who's dragging this out.

That said, I think I'm sniffing down a path now. Raised the wing and saw this damp spot. This is the side that cuts poorly.

Between my last post and today, I put the cylinders back on (that raise the wings) so that let me see this. Prior to doing that, I had taken the reliefs apart to see (with my uneducated eye) if there seemed to be any obstruction in there. I didn't notice anything.

Raised this and now, it might be making sense.

First, I don't know how small a leak can be, to impact the performance of a hydraulic motor. Seeing this, I'm wondering/guessing if there might be an internal leak in the motor and the oil is working past the bottom seal, giving me this situation.

Second, at the beginning of this year, I was getting mower attached to tractor and set off to do a shake down drive around. I was intrigued to find the blades were NOT moving. Long story short, the tank was very low on oil. The PTO was working and was operating the pump but, nothing was happening. Got to looking and discovered the oil was VERY low. Interestingly, the last time I had used it, I cut a field and set things away for the winter.....so where did all my oil go?

Though I'm still a bit perplexed with that, I'm now thinking I had enough oil then to cut what I cut BUT, was probably low (as I'm guessing it was dripping from here).

Today, I put the reliefs back on. I could not find a single place, out of four places I called (and stopped at), that would be able to set/adjust the hydraulic pressure breakpoint on these. So they are eyeballed to where I think they were when I got them.

My attention is now turning to the motor. I'm guessing something is blown in there or needs some kind of attention.

Now I need to find the numbers that were stamped somewhere on the motor so I can call and get the kit ordered.

 

[oldnslo]

Are there three hoses connected to the motor or just two?

 

[Richard]

Are there three hoses connected to the motor or just two?

First, there are three motors (15' batwing)

This is the first of two that are in series. This one has the supply hose (pressure) coming to it, an output hose that goes directly into the third motor BUT, this one also has a third much smaller drain hose (not sure of exact name) Frankly, I'm not too sure what this drain hose really does, but it has a third. Now, the second motor in this series only has two hoses.....the input from this motor and the output goes to the tank.

The middle motor only has two hoses. This is the only one of the three that has a third.

 

[Richard]

Oh, and I'm going out of town for a near week.....so I'm popping in and going to disappear again.

 

[Richard]

Or you could test pressure by interrupting the pressure input to each motor with a hydraulic "Tee" and mounting a inexpensive 5000 psi gauge on both motors. The gauges can stay there. Since relief valves are adjustable, the gauges would allow you to adjust as necessary.

The only slight problem in putting on guages is ordering the Tee with the right threads.

Question... (this has been on my mind and we have company in a couple weeks to this has risen in 'my' priority.....but not sure of the wife's.... her priority might be to make sure the petunia's are planted...


Anyway.... I might just buy some gauges and maybe leave them in place. Which brings me to a question....

I'm sure I can go to a shop and get a requisite Tee to fit. If the pressures are 2500 psi, my recollection is I'd want to get a gauge that maxes at double that amount, so a 5000 psi?

Aside from that.... get the parts, assemble and install. What then? If the break away is say, 2500 psi but, at idle (remember, this is on a 15'
mower so I'm not inherently comfortable sitting on top while it's screaming at PTO speeds)

Anyway, at blade engagement speed, I'd NOT expect the pressure to be 2500..... so do you crank it up to PTO speed to see where it registers? Do I get someone to drive the tractor while I'm sitting on the mower (yikes) and have them go into some dense growth which will then strain the limits more than no load on the blades?

Not sure how comfortable I am yet with this idea.... so am just trying to understand mechanically how it might be done.

Why?

Thus far, can't find anyone local (to the degree I've had time to try) that can test/set these. if I can incorporate them into the pumps full time, then I'm ok with that (until I smash one and decide it was a bad idea HA!)

Now that I'm thinking out loud about this..... it might make sense....something I read.

I have a memory that in the manual, to test, they recommend to CHAIN the blade carrier to a stump or something that won't budge.... then engage the PTO. I'm going to go back to see if I can find that in the manual. I might certainly be wrong but it does seem to me that you need to stress it to get it up to pressure a bit, no??

 

[LouNY]

You could get the fittings and a long hose to mount the gauge in the tractor. Just do one at a time or all 3 at one time on a manifold.
1/4" hoses 10 feet long for under $30 each.

Or get real fancy and get pressure transducers (transmitters) and run wires up to a display.

And yes to get to the max pressure you would need to almost stall the motor out.