Did I cause the shaft seal to blow?

[banjodunn]

G'day pump prob has an internal lube port that is overpressurising and blowing the seal by running bacwards, when you say the reservoir overflow letting the plow down is the engine running? I ask this as you will be pushing oil out of the cyl and not replaceing it ito the other side of the cyl therfore putting more oil into the res , I have seen this happen many times on FEL's when people shut the engine down and then lower the loader.



Jon

 

[J_J]

Have you considered that with engine off, and lowering the loader that the fluid on the base end is dumping to tank as the cyl collapses.

Do you think the rod side would be open to tank via the PB port sucking fluid in as the cyl collapsed.

If not, then the rod side of the cyl would pull a lot of vacuum, or air.

The cyl seems to be full of fluid when you lift again.

 

[lhfarm]

Stopped by a Case/IH dealer and got to talk to the service manager. He said these little pumps run full bore (no real relief built-in) and that I'm causing the pump to deadhead because of a problem with the pressure relief inside the control valve. There is an external adjustable rod, on the valve, but not sure what it does. But going to try changing it and see if it makes a difference.

 

[J_J]

I see a hose coming off the top of the tank. Is that not a breather for the tank.

The fitting on the left side with plug, is that where you fill or is that the fluid level when cold.

Can you show picture of the valve where the relief might be.

I did not read anything about the pressure setting for the relief.

If the relief should be higher than the pump specs, you might see seals pushed out or case busted.

If you need to, you can add external relief valve to protect the pump.

 

[lhfarm]

I see a hose coming off the top of the tank. Is that not a breather for the tank.

The fitting on the left side with plug, is that where you fill or is that the fluid level when cold.

Can you show picture of the valve where the relief might be.

I did not read anything about the pressure setting for the relief.

If the relief should be higher than the pump specs, you might see seals pushed out or case busted.

If you need to, you can add external relief valve to protect the pump.

The small hose coming off the top attaches to a fitting on the lower section of the ram.
The fitting on the left with the plug is the fill hole. I put the 6" extension here.
The cut-away of the valve shows how simple it is - just a couple of plungers. There is no pressure relief setting. Pull the knob out (or push the lever between the seats forward) and the bottom plunger shuts off the flow to the tank. Push the knob in and top plunger push a steel ball forward and releases the fluid in the ram (gravity down). I am wondering if one of he plunger is sticking and there is restricted flow back to the tank. That would build, I assume, be enough to build pressure in the tank and cause the deadhead condition. Correct?
There are no "O" rings or internal springs. I'm not sure, other than pump pressure what causes the plungers to retract.
Where would I put an external relief valve in this system?

Thanks

 

[J_J]

A relief valve should go after the pump, before the valve.

So if the valve makes the high pressure, the relief valve will relieve.

The relief flow should go to tank. You do know that when you open the valve spool to the cyl, the cyl is what develops the pressure, and that is determined by the load.

High pressure in the tank will deform the tank.

If fluid is pushed out of the tank, you have not left enough space for expansion, or air mixed fluid.

 

[oldnslo]

If this is a single acting cylinder I.e. gravity down, you will require a vent on the reservoir and a reservoir that is larger than the cylinder volume.

 

[J_J]

That hose coming off the top of the tank still puzzles me.

You say it goes to the bottom of the cyl, but I don't see a valve spool in line to raise the cyl.

I see the high pressure line off the top of the valve.

If there are two ports on the cyl, they may be using the cyl port to vent the cyl or store some fluid in the retraction mode.

Could the cyl be a DA cyl using the other to vent or to store fluid on the rod side.

Could the cyl be a SA cyl and using the breather port for fluid flow.

 

[Leejohn]

View attachment 424079

The small hose coming off the top attaches to a fitting on the lower section of the ram.
The fitting on the left with the plug is the fill hole. I put the 6" extension here.
The cut-away of the valve shows how simple it is - just a couple of plungers. There is no pressure relief setting. Pull the knob out (or push the lever between the seats forward) and the bottom plunger shuts off the flow to the tank. Push the knob in and top plunger push a steel ball forward and releases the fluid in the ram (gravity down). I am wondering if one of he plunger is sticking and there is restricted flow back to the tank. That would build, I assume, be enough to build pressure in the tank and cause the deadhead condition. Correct?
There are no "O" rings or internal springs. I'm not sure, other than pump pressure what causes the plungers to retract.
Where would I put an external relief valve in this system?

Thanks

I thank you are on the right track with the spool sticking and not opening all the way. Also check your adjustments and wear.

 

[lhfarm]

That hose coming off the top of the tank still puzzles me.

You say it goes to the bottom of the cyl, but I don't see a valve spool in line to raise the cyl.

I see the high pressure line off the top of the valve.

If there are two ports on the cyl, they may be using the cyl port to vent the cyl or store some fluid in the retraction mode.

Could the cyl be a DA cyl using the other to vent or to store fluid on the rod side.

Could the cyl be a SA cyl and using the breather port for fluid flow.

This is an old picture from when we restored the lift. The control valve sets on top, at the rear of the tank. The rusty fitting on top of it is the input side from the pump. The control lever, not visible here, is on the back side of the tank. You can see the hose from the control to the cylinder (which is under the frame). The "bleeder hose" (so called in the instructions) goes from the top front of the tank to a port near the bottom of the cylinder. When the take is first installed, the instructions say to attach the "bleeder hose" to the top of the tank, but not to the cylinder. You were to run the lift up and down several times and then attach the hose to the cylinder. I'm assuming that was to bleed the air out of the system.

I never understood why the "bleeder hose" was attached to the bottom portion of the cylinder. It was definitely not a 2 way cylinder. The original case was completely rusted, but we were able to re-use the rod and ports when we had the cylinder rebuilt.

I may have discovered a possible problem with the valve. The control lever, which actuates the valve, runs down and parallel to the back of the tank. When I was looking under the jeep to see if there were any adjustment points, I notice that the lever is actually canted toward the front of the jeep. I'm wondering if it was knocked out of alignment at some point and is no longer providing full movement of the valve. I'm going to see if I can make an adjustment and bring it back to parallel. I'll try to provide some pictures too.

Thanks for all the help.