Blowing Pump Seal on Pasquali 988

[whitetailer]

Hi Everyone -

Have a problem that I cant seem to get past. The seal on my hydraulic pump keeps blowing and I'm not sure why. First off, I'm no where near a hydraulic expert to be sure. I just want it to work.

I have a Pasquali 988 with FEL, PS and 3pt. The system is set up with a 5.4 GPM pump Open center @ 1500 PSI. All pretty straight forward.

I go from the pump to a Valve that then feeds the PS and 3 PT...OUT of that valve I then feed the FEL and then back to the tank. I wanted to give priority to PS then everything else.

I've attached a diagram of how I have it.

My question is, and I think where the problem is....with the Steering Return (no pressure) returning into the Pressure side of the FEL....so If I were turning AND lifting the loader at the same time wouldnt I get some back pressure in the system and this would cause my seal to blow? I'm under the impression that the seal should never have more than 10-20# against it...but something is wrong. I have a new pump coming and would like to route it all correctly to prevent this.

My new thought is...go from the pump to the FEL, then to Steering and return through the 3pt valve then to tank.

Thoughts?

 

[oldnslo]

I managed to get your attachment to open and I see a potential problem with the way the steering unit is plumbed. The steering unit tank line should connect back to tank and NOT into the pressure line feeding the FEL valve. Reason for this is that if you stall the FEL you will lose steering and also possibly damage the steering unit.

On Most gear pumps the seal chamber is vented to the pump inlet so blowing the shaft seal is usually caused by a high inlet pump pressure or worn bearings in the pump allowing excessive leakage into the seal area.

 

[whitetailer]

oldnslo - Thanks, I have a new pump to install....I'll be moving the steering return to the return side of the FEL valve. I think that will address that issue. Other than that I dont see anything else I can change.