Shower: no hot water, leaking

[Mstro8]

I have an old two-valve shower (no tub) that leaks cold water and no hot water comes out when I turn the hot handle.

Bought the house a year ago and the shower head leaked. It’s an old American Standard Aquaseal style (pics attached). I replaced the hot and cold valve stems and it worked for a month. Now, no water will come out when I turn the hot handle and the shower is slowly leaking again. Cold water still comes out. The sink is on the same pipe and the hot water works fine.

Is there a mixing valve somewhere that I’m missing? I don’t see anything behind the wall (pics attached). I took the valve stems out to inspect and they look fine. Any thoughts? Thanks so much!

 

[Twowaxhack]

Turn off the hot water at the source. Remove the hot valve stem. Turn back on the hot water at the source and see if it flows.

Start with that.

 

[GReynolds929]

I wonder if the old hot stem rubber is stuck in the seat.

 

[Mstro8]

Turn off the hot water at the source. Remove the hot valve stem. Turn back on the hot water at the source and see if it flows.

Start with that.

Just did that - the hot water came shooting out of the open valve.

 

[Mstro8]

I wonder if the old hot stem rubber is stuck in the seat.

The rubber on the old one was cracked but it all came out with the stem. I don’t see any pieces of anything left in there.

 

[Twowaxhack]

Just did that - the hot water came shooting out of the open valve.

Ok great. Now, turn the hot water back off……remove the hot stem again. Remove the shower head and cap the pipe with a 1/2” ips cap and then with the hot stem removed, turn on the cold water.

This will back flush the valve hopefully.

 

[Mstro8]

Ok great. Now, turn the hot water back off……remove the hot stem again. Remove the shower head and cap the pipe with a 1/2” ips cap and then with the hot stem removed, turn on the cold water.

This will back flush the valve hopefully.

Thanks for the quick reply! I need to get a cap and will try this. How long do I run the cold water to back-flush the valve? After that, do I just put the hot valve stem back in and try it?

 

[Twowaxhack]

Long enough to hopefully wash something out. Maybe 10-15 seconds , it would be helpful if you could tap on the valve body lightly with pliers while you do this. Might break something loose.

When I do this I don’t use water. I remove the shower head and connect a high pressure nitrogen bottle. Crank up the pressure regulator to 600 psi. Blows backwards through the valve to hopefully blow something out.