Post By Yelta
Group head unlocks under presssure - Sunbeam EM7000
I've had my Sunbeam EM7000 for over 3 years with no problems, and never any leaking from the group head. Yesterday however the group head started to unlock itself when pulling a shot. There is no problem when just running water through it, but when the basket is full of coffee, the group head will quickly unlock itself and fall out. I can just manage to hold it in manually, but only just. The only thing I can think that is different is that I recently wiped the seal in the collar to get the grounds out. I can't see anything obviously wrong with how the group head fits into the collar - it all seems normal.
Any ideas? Does the seal just need replacing? It just seems funny it suddenly went from perfect to falling out - there wasn't any gradual deterioration.
I donít have the same machine but if it is the group head seal, the portafilter would usually lock at about 5 o clock instead of dead center... If you try locking it in a little bit more does it still fall out?
Sorry do you mean the portafilter is literally dropping out of the group head?
How old is the current gasket and have you tried a fresh one?
Sorry, I didn't get my terminology right! Yes, the portafilter is dropping out of the group head. When pulling a shot, the pressure generated by the machine unlocks the portafilter until it drops out. Locking it in harder does not help, but with some force I can hold it in place while the shot is pouring.
The gasket is the original one that came with machine, so 3.5 years old.
Last edited by capnstoobie; 13th November 2017 at 10:46 AM.
Wow, this is the first time Iíve heard of a portafilter unlocking itself.
Good luck with the fix.
Just for comparison, I typically need to replace my seals on the Sunbeam every 14-16 months.
3.5 years is very old for a gasket. It's probably become very brittle and compacted. They are cheap and easy to replace. That's where I'd start your troubleshooting.
I had a similar problem with my single boiler Quaha (Lelit/Nemox etc).
The group handle used to untwist in the group head under pressure and start to leak.
I could manually hold it in place and everything would be fine.
I believe it was simply to do with wear of the locking lugs (for lack of better terminology) on both the group collar and group handle.
Not enough friction between the two.
I ended up buying a new group handle and it turned out to be much heavier with much thicker locking lugs - perhaps indicating that it was a common problem?
Saeco raises a good point. It's possible the portafilter "ears" are worn down from metal on metal friction. These are the lugs on the side of the portafilter body that bind it into the group head.
Replace your gasket regardless, but if you're still having issues, then the next step may be to replace the portafilter.
Thanks everyone for your help, some good advice there which I will follow up on
And it might also be an idea to put a "paper gasket" under the seal. It will help increase the pressure between the P/F and the group head seal.
I did this on my 6910, it worked for a while, then I had to replace the collar.
And one thing I have discovered is that different P/Fs, with different amonts of wear lock in different places.
Makes sense really.
But I can barely get a 7000 p/f in my 6910, and a new SS 6910 P/F only just goes in on the new collar, nearly to 6.00, whereas the older more used ones, around 10,000 shots on the original one, moves across to about 5.00.
But they all make good coffee~!
I reckon Saeco User is on the money, had a similar experience with my Silvia many years ago, got so bad the PF would drop right out.
Originally Posted by saeco_user
I rectified the problem by lightly dressing the bearing surfaces of the PF lugs and reducing the angle of the lugs slightly with a sharp flat file, easy fix if you are a bit handy, otherwise a new PF should also solve the problem.
Rawill also mentions the collar could be worn, so would pay to check both collar and PF, wear should be easy to see.
I've ordered a new seal, so I'll try that first.
If I need to buy a new portafilter, the only one I've found is $98 at https://spares.bigwarehouse.com.au/p...cts_id=1736066
Are there any other options that anyone knows of?
Yes! see my previous post, I doubt a new seal will solve the problem.
Originally Posted by capnstoobie
I did see your post I meant any other options for where to buy a new portafilter, or is $98 the best I'm going to find.
Originally Posted by Yelta
When you say "lightly dress" do you mean to rough them up a bit so there will be more friction?
No, I mean reduce the angle of the lugs slightly so they engage the collar more fully, looking at the bearing surfaces of the PF will reveal where the wear is occurring.
Originally Posted by capnstoobie
As I said, if your handy, it needs to be done slowly and with care.
Why not place an ad in the for sale section asking to by a PF in good nick? bet there are plenty out there.
Just an update - I received the new seal and replaced it. The old seal looked to be in good condition still, although as this was the first time I have ever replaced a seal so I didn't have anything to compare it with. The portafilter fits in more snugly now with the new seal though. When pulling a shot it does sometimes very slightly start to unlock, however it has not fallen out. Will see how it goes!