E61 mushroom O-ring dimensions

#1: Post by **tellicherry** » September 2nd, 2022, 9:03 pm

Does anyone know the dimensions of an E61 mushroom o-ring?

I'm having a bit of an unusual problem. I recently descaled my machine and decided to replace the teflon seals and o-ring in the grouphead. I purchased a re-build kit and all went well until I tried to reinstall the mushroom. With the new o-ring, I'm unable to get the threads of the mushroom to engage the group head. The mushroom will re-seat if the o-ring is removed.

I've purchased machine correct parts from Chris Coffee but I'm still completely mystified as to why I'm having this problem. With the correct dimensions, I figure I can try to find some thing that will work.

Thanks!

#2: Post by **Jeff** » September 2nd, 2022, 9:20 pm

They aren't standard!

They vary by manufacturer, and potentially if that manufacturer has changed the material of their mushroom or design (such as with a flow kit).

Internal valve lengths are another place where things vary by manufacturer.

VBM is seemingly "just different" on many things, such as how the mushroom is mounted, even before getting to solenoid groups.

If you've got the right o-ring, it might be that there's something binding getting it back in. (Chris' Coffee is pretty good at sending the right part if you confirmed with them the machine and rough manufacture date.)

#3: Post by **cafeIKE** » September 3rd, 2022, 10:38 am

If you have the old o-ring, you may want to trundle on down to the local hardware store. Our local has half a dozen bin boxes x a dozen sizes in Imperial and metric sizes. And shelves behind with hundreds of miscellaneous sizes. It helps if you have calipers or micrometer to measure the old and replacement.

I replaced one in our RV faucet Thursday and ended up finding the exact size in the 'misc' selection behind the standard sizes. The original was over sized for the 38mm channel and impossible to refit.

I've found over the past ½c. that o-rings may have standard sizes but vary considerably. One can almost build a truncated cone from various manufacturers 'standard sizes'