I have a 2000 f250 cc and the pump always runs. It has mile marker manual hubs installed by po. I took the vacuum lines off just past the solenoid and the line going to the heater is pumping good but the one going to the hubs has nothing. I don't know if po plugged it somewhere I dont see but I covered both and pump didn't turn off. pulled line off pump and plugged and turned right off. so basically somewhere around the reservoir its leaking. Any thoughts

 

It could be anywhere between the pump and the Hubs. The majority is rigid plastic tubing and unions. However, I have seen one where the rigid plastic had rubbed hole it. Just have to take some time to figure it out. I would start at the Hub Nipples and work backwards.

 

I blocked off at the first union on both and it didn't turn off. Is there something on the reservoir that can leak?

 

soapy water might help find leak re thought that you will need vacume pump or pressurize components & lines.

 

The reservoir certainly can leak. Disconnect the lines, plug one, draw a vacuum with a hand pump on the other and see if it holds.

The same thing that happens to them happened to me. I got a lot of stuff broke - AGE!