Cylinder rod pitting - How bad is this?

[LD1]

Actually....that is incorrect.

They ARE a single acting cylinder, but the packing and rod side DO see full PSI.

I wish I could find a pic, but I'll try to explain it best I can.


There is NO piston. The rod is the piston. The rod is only a little smaller than the bore. In the base of the rod, there is a grove cut, kinda like a 1/4" wide snap ring grove. In the grove is a TWO-peice part. It really looks like if you were to take a quarter inch thick washer, and split it in half, and put it in the grove. This makes up for the rod being a little smaller than the barrel. It is NOT a tight fit...and it is NOT a seal. It allows the ENTIRE cylinder to fill to full PSI. The gland packing on the end is what keeps it contained.:thumbsup:

I agree that they arent bad...so far. You need to pull the rams all the way out an see what the "hidden" part of those rods look like.

You can clean it up best you can and keep an eye on them. If you are using your tractors hydraulics, a little drip here and there isnt going to hurt anything. On an actual truck with power unit, it is a bigger deal cause you only have about two quarts of fluid til your out.

And as I said in the other thread, I wouldnt try rebuilding them. Just get new aftermarket ones. baileynet.com has them for ~$50/cylinder:thumbsup:

 

[dstig1]

Interesting. I would have thought there was an o-ring seal internally that did the seal. Thanks.

Yes, I need to flush them out and clean them up. Probably next weekend by the time I get to it. If they can be refurbed with minimal effort (flush and clean up pitting) then fine. Otherwise, I will replace if anything seems too sketchy.:thumbsup:

 

[wdchyd]

Interesting. I would have thought there was an o-ring seal internally that did the seal.

1 vee packing set #VS15004X100 ( Hercules Sealing Products-Hydraulic cylinder repair seals and seal kits, replacement cylinders and cylinder components for construction and many other heavy equipment industries. )

and 1 kw-1500 wiper seal ( http://herculesus.com/home.php?cat=1110 )

the v pkg set is just under the gland nut

 

[LD1]

Interesting. I would have thought there was an o-ring seal internally that did the seal. Thanks.

Thats what I would have thought too.....till I rebuilt mine.

Which explains why the packing is so extensive and not just a dust seal....because it indeed has to hold back the pressure:thumbsup:

 

[lostcause]

i've seen tons of them like that around here on snow plows that sit out all summer long. that's pretty minimal rust compared to many i have seen, and i don't think you will see any sort of noticeable leaks with them either.

i do have some questions though...

snow plows use these single acting cylinders, and when one is being extended the other is retracting. since they are single acting, i assume that when you are extending one there is some sort of valve that allows the other cylinder's fluid to drain back to the reservoir as it retracts. how do you account for this when hooked to a tractor? if you are using the bucket curl circuit for angling (i'm assuming this is how you do it?) you have a circuit set up for double acting cylinders with four hoses (two per cylinder). how do you hook this up and what sort of valve do you add in so that when one is under pressure the other is able to retract from the force.

also, in my experience, truck mounted snow plows seem to have some sort of bypass that will let the cylinders open/close if you hit an obstacle or bank that is too hard to help avoid damage. is anything like this needed on a tractor mount?

 

[dstig1]

I plan to add a cross-over cushion valve.

The diverter I have is bi-directional for fluid flow, so the one port gets fluid from the pump, and the other port would be the return side, as best I can tell. 2 independent single-acting cylinders running opposite directions should be no different than one double acting one in that regard...

 

[LD1]

I plan to add a cross-over cushion valve.

.

Definatally a must. The cylinders arent that big. And if you catch something with the edge of the blade, you want a relief to open. If not, you can cause a HUGE amount of pressure in the cylinder and hose, possible bending or exploding a cylinder, or rupturing a hose.

as best I can tell. 2 independent single-acting cylinders running opposite directions should be no different than one double acting one in that regard...

Correct.

 

[DK35vince]

Definatally a must. The cylinders arent that big. And if you catch something with the edge of the blade, you want a relief to open. If not, you can cause a HUGE amount of pressure in the cylinder and hose, possible bending or exploding a cylinder, or rupturing a hose.

I still don't get the need for this.
If these truck plows didn't need a relief valve for the front of a truck plowing at 10-30 MPH, why do they suddenly need one for a tractor that plows at 6-8 MPH?
If I hit something with my plow the trip springs flip the blade up over the obstacle.

 

[LD1]

I still don't get the need for this.
If these truck plows didn't need a relief valve for the front of a truck plowing at 10-30 MPH, why do they suddenly need one for a tractor that plows at 6-8 MPH?
If I hit something with my plow the trip springs flip the blade up over the obstacle.

The truck plows do have a relief.

It's called a crossover valve. It is usually set around 2000-2200psi and if the pressure exceeds that due to striking an obstical, the valve opens and diverts fluid from one cylinder into the other. Hence the name "crossover" valve.

The reason for the need to "add" one on a tractor is because on a truck, it is built into the power unit. When putting a plow on a tractor that has its own hydraulics, you loose the crossover valve part of the plow setup. So one needs to be added.:thumbsup:

 

[DK35vince]

The truck plows do have a relief.

It's called a crossover valve. It is usually set around 2000-2200psi and if the pressure exceeds that due to striking an obstical, the valve opens and diverts fluid from one cylinder into the other. Hence the name "crossover" valve.

The reason for the need to "add" one on a tractor is because on a truck, it is built into the power unit. When putting a plow on a tractor that has its own hydraulics, you loose the crossover valve part of the plow setup. So one needs to be added.:thumbsup:

Good explaination.
Thanks