631 won't build up pressure.

[mmortensen]

Hi. I have an old bobcat 631. The vane pump endhouse broked, I got a new house and a repair kit for the pump. But now it can not lift or something I've checked the shaft and everything else. There is fine flow but no pressure. I've bleeded it out again and again, but still no pressure. I put a hose on the block (on top of pump, don't know the name) and back to the tank = fine flow but no pressure. What can be wrong? It can run a little but not well.

 

[Tazza]

Did the shaft break in the pump? i assume you replaced it and the hose from the pump to the control block?
I'm wondering if when the shaft broke, metal got stuck in the relief valve in the control block. This will prevent you from beilding up pressure.
It will be screwed into the control block, they all look different but something like this:

Usually with the adjustment screw on the end, but not always. Sorry i can't be more specific.

 

[mmortensen]

Did the shaft break in the pump? i assume you replaced it and the hose from the pump to the control block?
I'm wondering if when the shaft broke, metal got stuck in the relief valve in the control block. This will prevent you from beilding up pressure.
It will be screwed into the control block, they all look different but something like this:


Usually with the adjustment screw on the end, but not always. Sorry i can't be more specific.

The shaft did not brake, only the end house. I replaced the hose to and there is no dirth in the relife valve. If i take the return hose from the controle block off, there is fine flow but i can put my finger in the hose and hold it back = no pressure. The same can i do whit the pressurehose from the pump.

 

[Tazza]

The shaft did not brake, only the end house. I replaced the hose to and there is no dirth in the relife valve. If i take the return hose from the controle block off, there is fine flow but i can put my finger in the hose and hold it back = no pressure. The same can i do whit the pressurehose from the pump.

I think you may need to open the pump up and see if something is wrong. There is no way you shoul dbe able to hold back the flow with your finger, something has to be wrong with the pump.