I have a home built in the early 80s (somewhere around 81-83) and there is an older Toro irrigation valve that is not working correctly. I don't know if the irrigation system is original to the house, but it seems to be at least 10-20+ years old if I had to guess.

The valve in question is an angled T-type valve and appears to be 1 1/2" (basing this on the fact there is a straight PVC coming out and into a PVC elbow, and the elbow has 1 1/2" on the side of it).

From what I can see online, it looks almost exactly like what the current 1.5" 252 series irrigation valve except that it has silver colored bands on the sides (metal rings?) where the water flow comes out. It is made of black plastic, the cap screws on with philips head screws, has a manual flow control valve in the middle with bleeder screw, and solenoid on the side. The solenoid has black wires instead of red also.

It looks almost just like this except for the metal rings on the out flow: http://www.sprinklerwarehouse.com/Toro-Irrigation-Valve-Flow-Control-p/252-26-06.htm

From what I can tell there might be some kind of problem with the diaphragm? I tested the solenoid after taking it off the valve and it seems to be working fine (hit it with power and the solenoid plunger pulls back hard, let off and it releases.. as long as good power connection there is no real loud buzzing sound). But when I connect everything and try to turn it on the sprinkler heads don't pop up. At the valve I can hear a high-pitched whistling sound. I tried adjusting the flow control knob all the way up and down and it did not send the water through to the sprinklers but I could hear changes happening in the whining sound (getting louder/softer etc). Also the sound only happens when power is running to the solenoid; there is no sound when power is off.

If I unscrew the bleeder screw then the sprinkler heads pop up. If I remove the solenoid then water sprays out of the port hole and the sprinkler heads pop up. But when I leave the solenoid on and try to have it activated with power it does not work.

Also there is some cross-threading on the cap where the solenoid screws on ...

I would prefer to purchase a new valve and replace the diaphragm, cap and solenoid from the new valve rather than having to replace the entire valve. Should the 252 series valve cap and diaphragm fit this older valve or has there been any significant changes in the product in the last 10-20 years where the design would not work correctly?

Thank you for any help you can provide!