“This pin E61 Style complete Preinfusion Valve is actually the equivalent part for the Rocket R58 #25 (exploded drawing) P/N R229905239 "Drain Valve". If this is what you're looking for, you've got it!”
“This isn't a review as much as it is information for those with the Rocket R58 machine.
This pin is the exact part required for the upper drain valve. With this complete set you will see the proper exhaust of left over water in the portafilter when you push the E61 handle down.
This part replaces Rocket P/N R229905239 (Drain valve)”
“After four plus years of daily use, my Rocket R58 1st Gen stopped "burping" out the exhaust valve reliably after I threw the brew lever back to closed - to shut down the shot. The burp is needed to depressure the puck before you unhitch the portafilter. I used this part to replace the preinfusion valve. The R58 machine now burps out the exhaust properly. It appears the end of the brass pushrod on this valve wears down over time where it rides on the cam of the brew lever. The wear eventually shortens the pushrod to the point the exhaust valve no longer opens. Plus, you get a new rubber gasket with this part, so it will seal under brew pressure like new. My gasket never leaked, but if yours is leaking, this could solve that problem. Don't forget to have the food grade grease on hand to lubricate the end of the pushrod before reassembly.”