Two solenoids lower spindle, but it won't raise again... suggestions?
Solenoid valves come in many variations, sort of analogous to normally open and normally closed contacts, but they also need to provide a path for the air (or hydraulic fluid) to escape the cylinder. 

In your case you have a double-acting cylinder since there are no springs. Here is one way to operate a double-acting cylinder using two 3-way valves from this reference: 



You force air into one port to extend the cylinder, allowing air to exhaust from the other part. Retracting the cylinder is just the opposite. There is a more force available when extending the cylinder since the whole bore area multiplied by pressure is available when extending, whereas the area of the rod must be subtracted from the bore when calculating the retraction force. 

Both valves would be powered at the same time to extend or retract the cylinder (depending on the valve type and how the valve ports are connected to the cylinder ports). 

It sounds like one of your valves is not operating correctly.