# Gaggia Classic - from light modding to major surgery



## nomilknosugar (May 9, 2017)

I thought I'd quickly fit one of MrShades' PID to pimp, sorry: mod my classic a bit.

However, I quickly found out that the gods of espresso machines have a wicked sense of humour! Here's my tale so far:

I opened the machine, marked the connections and took the boiler out. "That was easy", thought I, and took a closer look.

"Hmm, nothing in any manual mentioned a massive jubilee clip, funny! What's it doing? What, hugging the brew thermostat tightly to the boiler? I wonder what happens when I undo the clip... oh, the thermostat falls off? Shouldn't that be screwed... ah. I see."

Yes, the brew thermostat screw had sheared off and was stuck in the aluminium. One of the previous owners did a dirty repair (it worked, I have to admit) and the knowledge of this got lost somewhere along the way of the journey of this particular Classic.

A quick cry for help to the intrepid MrShades and yes, he had come across this before, so could give me a tip or three. He really is a legend and deserves all the praise he gets on this forum!

Cue some quick drilling, which unfortunately failed to remove the screw, but at least I've got a hole where the thread needs to be, so I'll get my hands on a tap & die set tomorrow and try to cut an M4 thread into the mess of brass and aluminium where the new thermostat needs to go.

"Right, while I'm at it, let's look at the group head a little more to see if my backflushing this morning made things look nice & clean under the shower screen. Oh, it hasn't. Ok, let's look underneath the group head. Yuck! And the gasket? Should it be that rock hard? Let's take it out. Out! OUT! Not by hand, perhaps with a screwdriver..."

Ten minutes of hacking away later, I was able to extract an original, vintage 2006, crumbly, gunk encrusted group head gasket in several pieces. Not even good for the museum, I'm afraid. Off to order a new one, no, make it two, and how about a new shower screen as well? That IMS one looks tasty... (and I felt I deserved a treat after this.)

So, off to Screwfix tomorrow to buy a tap & die set, then I'll hopefully be able to continue with fitting the PID. Add to that a thorough clean, a new gasket (should arrive on Friday), then I may even be able to make a shot of espresso again.

Until then and in the meantime, repeat after me: "I will not open the boiler. I will not open the boiler. I will not open the boiler..."


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## nomilknosugar (May 9, 2017)




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## Stanic (Dec 12, 2015)

did you get the cafelat silicone group gaskets?

c'mon, you know you want to give that boiler a proper de-scaling


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## koi (Oct 12, 2014)

Nightmare when unexpected issues crop up on something that should be straight forward.


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## lake_m (Feb 4, 2017)

Looking at that photo, there doesn't look like a lot of 'meat' left to tap that hole, plus the cracks either side don't look too good. Go steady!


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## jimbojohn55 (Jan 15, 2016)

https://www.thebottomlesscoffeeshop.co.uk/index.php?route=product/product&product_id=84&gclid=CMb2lN_YrdQCFdgGgQodCOYKnQ

Tempting to fit a new boiler - but I appreciate your approach, go for it - but defo open the boiler, flat the base and fit a red silicon boiler seal - bot and braces approach.


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## nomilknosugar (May 9, 2017)

Stanic said:


> c'mon, you know you want to give that boiler a proper de-scaling


You evil person!


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## nomilknosugar (May 9, 2017)

lake_m said:


> Looking at that photo, there doesn't look like a lot of 'meat' left to tap that hole, plus the cracks either side don't look too good. Go steady!


Luckily, what looks like cracks on the photo seems to be more of a shallow slit that someone appears to have cut with a hacksaw. I'll have another close look with better lighting tonight. With regards to the "meat", MrShades told me of someone with the same problem who ended up cutting an M5 thread into it and got a modified sensor to fit, so I'm not too worried. Yet.


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## nomilknosugar (May 9, 2017)

jimbojohn55 said:


> https://www.thebottomlesscoffeeshop.co.uk/index.php?route=product/product&product_id=84&gclid=CMb2lN_YrdQCFdgGgQodCOYKnQ
> 
> Tempting to fit a new boiler - but I appreciate your approach, go for it - but defo open the boiler, flat the base and fit a red silicon boiler seal - bot and braces approach.


Oh, that's a LOT cheaper than I thought it would be! Many thanks for the link, this is definitely plan B. I will leave the boiler alone for now, though. It doesn't leak, so I can only make it worse by opening it.


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## Norvin (Sep 10, 2014)

Most thermocouples that I have seen come with a 6mm coarse threaded fitting (although I do have one here with a 7.7 (M8?)x 1.25mm fitting). I think that Mr Shades modifies them to mount in a 4mm fitting so that they screw directly into the boiler. Looking at the state of the boiler, It may be easier to drill and tap the boiler to M6 x 1.25mm coarse (or 1/4" BSW which is just about the same) to take the standard unmodified thermocouple.

Alternatively, you could not do anything and just strap the naked (without any fitting) thermocouple to the surface of the boiler with a bit of heat paste.


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## Richard_severn (May 3, 2017)

If you are getting the new shower plate I would recommend getting the brass bit that goes above. Increases the thermal mass of the boiler by a lot so you have better temp stability. I think I paid 15 for mine. I started a thread with all the links to various gaggia mods and that has a link to the brass plate









Also you should open the boiler just so you know what your dealing with







if the thermal couple was held on by a jubilee clip what else has been done to the poor machine.


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## nomilknosugar (May 9, 2017)

Has anyone else's espresso machine turned into "my grandfather's axe"? Looks like by the end of the "mod" I'll have replaced every single part of it!


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## nomilknosugar (May 9, 2017)

Norvin said:


> Most thermocouples that I have seen come with a 6mm coarse threaded fitting (although I do have one here with a 7.7 (M8?)x 1.25mm fitting). I think that Mr Shades modifies them to mount in a 4mm fitting so that they screw directly into the boiler. Looking at the state of the boiler, It may be easier to drill and tap the boiler to M6 x 1.25mm coarse (or 1/4" BSW which is just about the same) to take the standard unmodified thermocouple.
> 
> Alternatively, you could not do anything and just strap the naked (without any fitting) thermocouple to the surface of the boiler with a bit of heat paste.


I think it's not unwise to start with the smallest threading and work my way up if I balls it up. MrShades is happy to swap my sensor to a larger threaded one if needed. I just need to find a tap set to borrow, or buy one. I'll update this thread with my further adventures...


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## MrShades (Jul 29, 2009)

You may want to see if @Jollybean has any additional input into this... as it was he who tapped the original m4 hole out to m5 for a very similar reason.

Personally, I'd go m5 first!

m6 would complicate things further - as my sensors are all custom made by me, and certainly don't start off with m6 screws prior to manufacture.


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## MrShades (Jul 29, 2009)

Agghhh - double post - mod please remove if poss.


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## nomilknosugar (May 9, 2017)

M4/70 thread successfully cut. And the set of tap & die was cheaper than a new boiler. ;-)


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## MrShades (Jul 29, 2009)

nomilknosugar said:


> M4/70 thread successfully cut. And the set of tap & die was cheaper than a new boiler. ;-)


Well done!


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## timmyjj21 (May 10, 2015)

From the pics, the boiler seal is definitely blown and leaking... You probably should open it and either hand lap the boiler face smooth again, or buy a new boiler! Someone had to say it....


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## Jollybean (May 19, 2013)

Good news that you managed to cut the m4 thread. If for any reason you do need to go to m5 I think I still have some of the adapters I used. Let me know and I can send a couple to you or Mr Shades if you need a purpose made cable.


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## nomilknosugar (May 9, 2017)

timmyjj21 said:


> From the pics, the boiler seal is definitely blown and leaking... You probably should open it and either hand lap the boiler face smooth again, or buy a new boiler! Someone had to say it....


Apart from the appearances on the photo, what other symptoms should one expect? The machine worked fine. I am not going to touch the boiler this time round, unless I can see an actual problem when I restart it after finishing fitting the PID. Frankly, if it all goes to hell in a handcart, I'll probably go back to drinking tea (or buy a better model).


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## timmyjj21 (May 10, 2015)

You will not have major symptoms except a slow ooze at the boiler seal that evaporates quickly when at temperature. It will slowly get worse and turn into a bigger leak as the aluminium gets more pitting developing. If you descale now, any semblance of a seal from the scale in the joint seal will be removed and it may turn into a massive leak.


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## nomilknosugar (May 9, 2017)

Thanks, that's very helpful. The machine has actually just been descaled by the guy who sold it to me. I will see if everything works with the PID first, then get my head round boiler maintenance (and pressure adjustment) as the next project(s). There's a dodgy bolt between boiler and group head already, so I don't want to risk ending up with a "wreck with a PID", at least for another couple of weeks...


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## timmyjj21 (May 10, 2015)

Define 'Dodgy Bolt'! When the boiler starts leaking it is pretty standard for the cheap galvanised steel bolts to start corroding and locking themselves in place. It can sometimes be a nightmare to remove them, to the point of being unable to undo via conventional means. When I do refurbs I always replace with stainless steel bolts to hopefully avoid this issue.

Edit: just looking again at the photos, it actually looks like the previous owner tried to cut a slot to undo the boiler bolt with a flat screwdriver and failed, probably snapped the thermostat off accidently when holding, then tried to get the thermostat piece out and failed, so bailed out bodged it together, and sold it...

So I hate to say, my comments on stuck bolts are probably relevant. Plenty of advice on this forum. I'm a fan of ripping the bolt heads off and then tapping a Stanley knife blade between the join to seperate the halves!


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## nomilknosugar (May 9, 2017)

Thanks for cheering me up. Some more light DIY to look forward to - this might be the occasion to justify getting that acetylene torch I always wanted!


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## nomilknosugar (May 9, 2017)

Just a quick update - PID installed, gasket installed, first shot of espresso tasted rather good. Now I'll let the dust settle, before I proceed to Phase II (The Return of The Shedi).


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## timmyjj21 (May 10, 2015)

Yeah, sorry, it was a pessimistic last post, but I honestly love a good refurb!


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## nomilknosugar (May 9, 2017)

Keep telling me how it is - I'm a newbie and glad for any pointers!


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## nomilknosugar (May 9, 2017)

Well. Here's a shiny, new "toldyouso" card for @timmyjj21 with an invitation to wave it in my direction.

The PID works as it should, but the rest of the machine hasn't taken too well to being shaken about.

The boiler now does audibly and, dare I say, drippily leak when I turn the steam on.

After cleaning the group head and changing the gasket, it now also leaks around the portafilter when I pull a shot.

Hmm.

I've got to sit down with myself and decide what to do now. To run with the topic theme: Should I take the machine back to theatre as suggested, attempt a clean-up and resurface of the hip joint, sorry: boiler plate? What if the thing is so corroded that I'll have a corpse on the operating table? Is it worth throwing good money after bad? Should I replace the boiler and perhaps the group head? Buy another Classic and cobble together a "Frankenstein"? Or cut my losses and upgrade to a mid range machine?

I think there's a good think to be had, best over a nice coffee or two. Perhaps it's time to visit the Exploding Bakery up the road in Exeter today for a meeting with myself on neutral ground (I believe they're selling Crankhouse Coffee, delish!)

(To be continued, probably.)


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## MrShades (Jul 29, 2009)

The main problem you have is with the actual boiler - the aluminium part (not the group head, which is mainly brass) is pretty knackered on a number of fronts!

If it were me, I'd buy:

- a new boiler (about £36.99 - ebay)

- a set of seals (about £4.50 - ebay)

- a set of new stainless hex screws - because you'll either need to dremel the existing ones off completely, or slot them or otherwise kill them in separating the boiler from the group head (again, ebay will be good for these)

The group head itself usually cleans up well - the corrosion and scale normally attacks the aluminium.

So - £45 invested - and a bit of time, and you'll be good as new!

It's a good learning process anyway... just be prepared for a fight in separating the boiler (If stubborn, then I use very good impact sockets [they're very hard], a long extension, and a fair sized ratchet handle on the top) if the bolts are rounded off already, then dremel a slot in them and use a large flat bladed screwdriver socket. It's often impossible to get sufficient leverage using normal screwdrivers - you really need the additional power of a socket set, and still a fair amount of force!).

Good luck - and keep us posted on progress.


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## timmyjj21 (May 10, 2015)

As above!

The portafilter leak is interesting. Is the brass knackered or distorted at the group collar? The other option is if the new seal isn't bedded in correctly: Has all the old group seal residue been removed? Dried crumbs and old coffee crap will be an issue. Has the new seal been put in the correct way? Rounded edge of the seal goes in with sharp edges out to seal on the portafilter. The inner surface is usually the one with writing on it too.

Once the seal is inserted, put the portafilter in and turn it solidly to bed the seal nicely.

If you are time and tool rich, it's still perfectly serviceable, but no matter what the aluminium top needs to be removed in order to renew the old part or replace with a new.


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## nomilknosugar (May 9, 2017)

Ok, you've twisted my idle thumbs - I'll give it a go.

It's far from an easy ride though, this is how far I've gpt:

- Boiler removed (it's so dimple the second time round).

- Boiler/group bolts duly stuck, will need to find a vice and more heavy duty tools.

- Steam valve bolts removed, but the valve dow not want to come off. Looks like it's chemically bonded to the boiler aluminium.

Question: is it ok to use WD40 on the stuck parts, or am I going to contaminate the machine forever? Any other ideas how to get the steam valve off?


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## bluebeardmcf (Nov 28, 2016)

Wish I'd read Timmyjj's solution before I attacked my last one (now up and running fine) - I used a dremel to cut slots and hit the screws with an extension bar on an impact driver, took ages.

The steam valve has been tight on both Gaggias I've revived. I personally wouldn't use WD, the Ali is likely porous and may stink forever of fish oil and paraffin. I soaked the valve and boiler for a few hours in descaler, applied a short blast with a mini blowlamp, and gradually worked at it by prising upwards with a couple of blunt screwdrivers, working around from various angles. Obviously go carefully...


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## nomilknosugar (May 9, 2017)

Thanks, @bluebeardmcf - a nice soak in ca 7% citric acid solution did the trick. Not only did I get the steam valve off, it also looks nice & shiny 

The flipping bolts remain stuck, though, despite soaking and blowtorching. More brute force required, I reckon.


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## nomilknosugar (May 9, 2017)

Update: bolts, meet Mr Dremel. 1/4 done. (Boiler will be replaced, so let's just go for it!)

Edit: 4/4 - bolt heads removed.

However, boiler and group head sing this song to me:


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## timmyjj21 (May 10, 2015)

The bolts get scale and corrosion in the aluminium part only. This part has no thread and just get glued it in place by corrosion. The brass base has the threads, but the bolt remnants can be easily unscrewed once the halves are seperated.

Buy a pack of Stanley knife/ box cutter blades. Tap one into a corner near a bolt using gentle, careful hammer taps. Wiggle it around along the joint and then pull it out with pliers or mole grips. Then go to another corner and repeat, or just use another blade. Expect the sharp edge of the blade to chip off when trying to pull it out, but the basic aim is to loosen the bonded bolt remnant from the aluminium. I've had to do this on 3 machines and it's worked every time. With care, the brass base will not be damaged and any damage to the aluminium upper part is removed when you renew the boiler face ( if salvageable!)


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## nomilknosugar (May 9, 2017)

@timmyjj21 - where are you? I want to buy you a pint!

With much hammering, destruction of Stanley blades and a fair bit of swearing, I achieved separation (or rather, permanent divorce!) of boiler and group head. The state of affairs - see photos below.

At the moment, there's still one bolt stuck in the brass and it really doesn't want to go. Robogrip, descaling, WD40, blow torch, more swearing - so far unsuccessful. But it'll go eventually, and if I have to drill the little soandso out.

Off to order my boiler and assorted gaskets now.

Again, many thanks to you all for your much needed advice!

I'll shut up for a bit now - the AeroPress and this fortnight's Has Beans are calling...

Cheers, folks!


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## nomilknosugar (May 9, 2017)

Sad state of affairs!










There's always one&#8230;


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## lake_m (Feb 4, 2017)

Enjoy your well earned coffee. Thanks for the write up - enjoying it.


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## bluebeardmcf (Nov 28, 2016)

That boiler is ok, just needs a clean


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## nomilknosugar (May 9, 2017)

bluebeardmcf said:


> That boiler is ok, just needs a clean


Make me an offer and it's yours.


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## timmyjj21 (May 10, 2015)

Far out. Those bolts look like crap! I've never had one that bad. Usually you can easily unscrew them.

Hopefully a few days of WD-40 will loosen it while you wait for parts.

The top boiler half looks pretty good and you may not need to buy a new one.


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## jimbojohn55 (Jan 15, 2016)

I agree with timmy, flat the base with 120, 240, 600g wet and dry, if you have ordered a new boiler fair do, but put the old one on the sale thread it will sell for a £10


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## bluebeardmcf (Nov 28, 2016)

nomilknosugar said:


> Make me an offer and it's yours.


Not for me thanks, I already have 2 spare classics I ought to sell.


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## nomilknosugar (May 9, 2017)

Amazing how well the brass body of the group head conducts heat away from the one, lonely, intrepid remaining bolt. I've blasted it with my little kitchen blow torch for a couple of minutes. Did it start to glow? Did it hell. All I got was a slightly warm group head - there went the idea of heating and cooling the bolt into compliance. With every passing trial of something new, I'm but one step closer to having to drill it out. Meh. Let's try another few hours with 3-in-one penetrant spray, not that the first few made any impression...


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## bluebeardmcf (Nov 28, 2016)

I think the melting point of brass is quite high... I wonder if putting it on a hob for a few minutes would help? Lovely smell in the kitchen if you haven't got a camping stove...


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## timmyjj21 (May 10, 2015)

Heat the brass to expand it, put an ice cube on the bolt to shrink it.


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## nomilknosugar (May 9, 2017)

I tried heat & freezer - didn't work. As I said, it's because the heat gets conducted away by the brass immediately, and I'm not going to get the whole thing to red glowing, as it'll wreak havoc with what's left of the chrome plating.

This morning, I have used the dremel to remove as much of the corrosion at the steel/brass interface as possible so the penetrating fluid has a better chance to get between the two surfaces. I have also flattened two sides of the bolt to get a better grip. I'll try again tonight, clamping the bolt in a vice - and very likely causing it to shear off. Next attempt will be drilling out. Interesting times!


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## nomilknosugar (May 9, 2017)

Without words:


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## MrShades (Jul 29, 2009)

Where there's a will (and a vice, lots of penetrating oil and a significant amount of brute force) - there's a way...

Well done! Onwards and upwards from here surely.

Unless you know differently???? Keep us all posted...


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## nomilknosugar (May 9, 2017)

Oh yes, onwards and upwards! Gasket set and thermo paste arrived today, new boiler and stainless screws (I know about not tightening them too hard) are in the post. Tempted to treat myself to a brass shower head holder - is it worth it?

By the way, the old boiler is in quite a state after inflicting my combined gentle persuasion techniques on it, so I'll leave the restoration for the long, dark Dartmoor winter evenings.


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## lake_m (Feb 4, 2017)

I thought you were about to show us a picture of a sheared bolt, but no, you did it! Well done!


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## MrShades (Jul 29, 2009)

I like brass dispersion plates... in my view anything that increases the thermal mass of the brew path is a good thing, as it should improve temp stability.


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## nomilknosugar (May 9, 2017)

I note that the holes are smaller than in the aluminium plate, which should give less flow at similar pressures. I think I'll see if the old plate does the trick without leakage after cleaning it up, it looks rather battered.


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## nomilknosugar (May 9, 2017)

(Just an update - I'm still waiting for the boiler, which will arrive tomorrow. Looking forward to the assembly tomorrow night and then finally, hopefully(!) a lovely morning coffee on Saturday.)


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## nomilknosugar (May 9, 2017)

Shiny new boiler arrived. Machine put together, electrically all is well and the PID works as expected. There are a few problems with water flow and leakage though:

1) When switching on the pump without a portafilter in place, more water pours around the shower head than through it.

--> My feeling it that this is likely due to a horribly corroded dispersion plate, which is sitting anything but flush with the group head.

2) When pouring a shot, water still leaks around the portafilter despite a new gasket being in place.

--> No idea why this would be, I made sure the gasket is the right way round. Help?

3) When steaming, there's some leakage coming through the group head (I think), and I can hear it hiss from inside the machine.

--> I will take the lid off tomorrow and take a look where it leaks.

4) I managed to bend the steam valve, so the knob rubs against the chassis and it's not quite true.

--> Tough luck.

I did manage to pull a halfway tasty shot, though, despite the obvious problems.

Onwards and upwards, ho hum, and all that jazz.

[To be continued, I'm afraid.]


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## El carajillo (Mar 16, 2013)

Remove the dispersion plate and check there are no bits of debris / crap stuck where the seal sits.

Press the dip/plate into the seal (in hand)seal should be a firm fit on the plate.

As a short term fix, flat the top of the dis/plate on a piece of wet&dry paper ( very lightly)

Ref steam valve knob rubbing, just slacken the two hex bolts holding it to boiler and rotate the valve to centralise the steam knob in the aperture.


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## nomilknosugar (May 9, 2017)

I think my disp plate is beyond redemption, the edges on the top where it sits against the group head are so worn, it's nearly flush. There's pretty much no scope for flattening it smooth. I've just ordered a brass dispersion plate, let's see what happens.

I'll do the valve readjusting thing tomorrow, thanks!


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## timmyjj21 (May 10, 2015)

1) Yep, dispersion plate! Although it should form a seal on the inner edge of the group gasket, yours must be pretty trashed!

2) Really odd. Is the basket edge damaged or dented?

3) Check for leaks, but the group head sometimes hisses due to water boiling around the dispersion plate when it gets hot enough. Possibly also consider the solenoid valve leaking, but significantly less likely.

4) Steam valve takes a lot to bend! It's probably fine and just need to be rotated a fraction as per El Carajillo


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## nomilknosugar (May 9, 2017)

1) I just checked, there is no contact between disp plate and gasket. I wonder if I got sent the wrong gasket, I'll measure the thickness tomorrow.

2) See 1)


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## timmyjj21 (May 10, 2015)

The group seal should be 8.5mm standard e61 style. For the price difference I would go a blue Cafelat silicone one.


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## nomilknosugar (May 9, 2017)

I have narrowed the problem 1) down to the dispersion plate, though. It is so worn, it wobbles in the group head unless I whack the screws really tight, and there's so little room for the water to get from the group head hot water (entry) hole to the four holes in the disp plate, that it squirts out the sides nearly as much as it does come through the holes. There's very little water coming through the two holes on the far side of the water entry.

I've ordered a brass disp plate and will add a silicone seal to the order as suggested.

As to 2) the handle of the portafilter has to be beyond 6 o'clock, so the seal may be a bit shallow, even though it was sold as "9mm". I expect this to be better with the silicone seal.

The good news re. 3) is that the hissing and dribbling on steam temperature is just from the wet disp plate, as suggested. I opened the machine and set it to steam, it's dryzabone inside!

As to 4), it worked, but the turning part of the steam valve is definitely, let's say "eccentric". ;-) I can live with that.

Cheers folks, I'll really have to tidy up the tools now and get outside into the summer! Have a good weekend!


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## timmyjj21 (May 10, 2015)

The eccentricity of the steam knob may just be positioning too. I've seen them often put back on the wrong way. Look inside the knob- The metal spring (you don't loose it did you?!) goes against the curved side of the spindle, and flat area of plastic matches to the flat side of the spindle.

It still fits if put on the wrong way, but the knob isn't central.


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## nomilknosugar (May 9, 2017)

Nope, that's not it. No worries, I'm rubbish steaming, whether wobbly or not.


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## MrShades (Jul 29, 2009)

nomilknosugar said:


> Nope, that's not it. No worries, I'm rubbish steaming, whether wobbly or not.


Hmmmm from what you've described my immediate thought was that the steam knob needs removing, rotating 180 degrees and refitting - as Timmy said, but if you've tried this then I'm at a bit of a loss.


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## nomilknosugar (May 9, 2017)

I guess it may have had a bit of an accident before I took it off... looks like the end bit is just bent. I am not going to try and unbend it, lest it snaps off. Really no bother.


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