Did I cause the shaft seal to blow?

[lhfarm]

I have a 3 point lift on my 1949 Willy Jeep CJ3a. I have a history here of trying to get the hydraulics working. I finally purchased a new pump and the rest was working great. Took the jeep with a 400lb plow attached to a show last weekend. When I went to left the plow to load the jeep on my trailer, the lift was slow. Today, I thought I'd make sure the fluid level was good. This is a "closed" system - no breather. I took the plug out of the filler pipe and it showed fluid. So I started the jeep and lifted the plow. It went you fine and when I lower it, fluid shot out of the plug opening. So I stuck a 6" extension thinking that would help me "burp" the system. Fluid kept squirting out when I lowered (gravity down). After a few trips up/down, checked up the hood and fluid was flying from the front of the pump.

When I removed the pump, I could see that the seal is deformed. I can't be sure it wasn't leaking earlier. I have a spare seal from my days of trying to repair worn out pumps. Putting it in now and would like to make sure it doesn't happen again. So being a new pump, I guess it is possible that the seal was defective, but I'm more concerned something else isn't correct. Any ideas?

 

[bigdeano]

I'm wondering why you don't have a vent on the reservoir tank. The seal blew because it built up more pressure in the tank than the seal could withstand. I would put a vent on the tank and lower the oil level so oil doesn't blow out.

 

[J_J]

You say a closed system.

A closed system is when the output is fed back into the input after being used.

Any excess or flushing fluid is sent to tank which must be vented.

That fluid is going to heat up and needs to vent.

 

[lhfarm]

I'm wondering why you don't have a vent on the reservoir tank. The seal blew because it built up more pressure in the tank than the seal could withstand. I would put a vent on the tank and lower the oil level so oil doesn't blow out.

Here is the background story - http://www.tractorbynet.com/forums/...ic-system-quit-how-3.html?highlight=hydraulic

You say a closed system.

A closed system is when the output is fed back into the input after being used.

Any excess or flushing fluid is sent to tank which must be vented.

That fluid is going to heat up and needs to vent.

JJ - You might remember my adventures with this system. Since it is the equivalent of an antique tractor system, I've not made any modifications. I'll try to fashion a vent and let you to know how it works.

Thanks,

 

[lhfarm]

I wasn't able to find the required seal from the shop were I got the pump. They had me order the seal from Case/IH, but it is too big. The Case/IH parts guy found a close match, but it blew shortly after the hitch started to lift the plow. Before I started the jeep, I drained the fluid and installed 4 quarts of the IH fluid used with these pumps. I also put a 6" pipe extension in the fill tube, as a vent (didn't replace the plug in the fill tube).

At one point during the lift test, fluid came out of the vent pipe (~five inches above the top of the reservoir). I'm not sure if this was before or after the seal blew. If the system is now vented, there still seems to be excess pressure at some point (enough to raise the fluid five inches in the vent tube).

I'm at a loss as to next steps (other than to find a correct seal). Any suggestions appreciated.

Thanks,

 

[bigdeano]

How large is the reservoir tank? Maybe you're overfilling it. Are you sure the pump you bought is made for the direction you're turning it? I suppose you've been through all this before.

 

[lhfarm]

How large is the reservoir tank? Maybe you're overfilling it. Are you sure the pump you bought is made for the direction you're turning it? I suppose you've been through all this before.

The original 1947 instructions can be seen here - Farm Jeep -Newgren Installation Instructions

The last step is to add 5 quarts of 10W oil, so I'm assuming that would be the amount needed to fill the reservoir and the lines (which run from the front to the back of the jeep). I drained the reservoir and most of the fluid in the lines and added back 4 quarts.

The pump is the same type used in '47 (fits IH C & A tractors), so I believe the direction is correct. The ports on the pump are the same size, and it is possible that I have the manifold fittings reversed. I can't see the details in the instructions. If I had the the suction and pressure sides reversed, would that cause the same problems as a pump running backwards? No real understanding of what I'm doing.

I did at one point (thanks to JJ) fill a bucket about have full with fluid and just ran the pump. It appeared to be correct. Perhaps I should run that test again.

Any and all suggestions for what to check are welcome.

Thanks,

 

[J_J]

On a lot of pumps, the suction port is larger.

Some pumps can rotate in both directions.

Excerpt about rotation:

Pump rotation is dependent upon the proper
orientation of the heat shield, backup gasket, and rubber
seal in the front cover housing, the center section
and rear cover, respectively.

 

[lhfarm]

On a lot of pumps, the suction port is larger.

Some pumps can rotate in both directions.

Excerpt about rotation:

Pump rotation is dependent upon the proper
orientation of the heat shield, backup gasket, and rubber
seal in the front cover housing, the center section
and rear cover, respectively.

I have three old pumps, plus the new one. The new one is the only one with a rotation arrow stamped on the top. According to the arrow, I am running the pump backwards. However since this was the same pump that came with lift back when, I'm assuming that is not the problem - these pumps can run in either direction. As stated the ports are the exact same size. Among the 4 pumps are 3 different (but minor) internal designs. It is possible that some change was made and the newer pumps won't work in both directions? Are there pressure relief ports I should see on the output side of the pumps? If those are now on the suction side, I'm assuming that would be the problem.

Thanks,
Barry

 

[J_J]

Some pump relieve internal and others relieve external.

You should try and find the specific data on the pump you want to use.

I believe the pump relief should be on the output and relieves back to the input.

So if you reverse the ports, your relief in now on the input and no relief for the output.