# Guide on complete strip down and refurbishment of Gaggia Classic.



## DRAXXMENVONE (Jun 19, 2018)

Hi folks.

I've got a working but leaky Italian made Classic I've had lurking in the garage for some time. I thought since I'm going nowhere for a while, it's time to strip it down and fully refurbish it.

Is there a definitive guide or collection of guides anyone has found to do this? I'd like to do a good job and learn as I go.

I'm fairly handy and have repaired appliances before but reckon this'll be the most challenging yet!

Any advice much appreciated.










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## worzel (Apr 9, 2020)

Hey there, I did my first service yesterday based on this YouTube video. All went well!






I have a used 2003 Classic and although it had light use the coffee tastes so much better after!

Graham

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## DRAXXMENVONE (Jun 19, 2018)

worzel said:


> Hey there, I did my first service yesterday based on this YouTube video. All went well!
> 
> I have a used 2003 Classic and although it had light use the coffee tastes so much better after!
> 
> ...


Aw. Brilliant thanks! I'll have a look at this. I've got the kit, just need to make sure I've got the tools.

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## worzel (Apr 9, 2020)

DRAXXMENVONE said:


> Aw. Brilliant thanks! I'll have a look at this. I've got the kit, just need to make sure I've got the tools.
> 
> Sent from my iPhone using Tapatalk


I would make sure you have replacement gaskets and o rings. The espresso shop sells them in a pack but I bought them separately as I already had some items in the pack.

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## allikat (Jan 27, 2020)

Replacement gaskets and o rings are a must. If your machine is over 10 years old, then replacement boiler bolts are strongly recommended. M6x16 galvanised is what you need. They're zinc coated steel bolts holding an aluminium boiler to a brass brew head, and when they rust, they go nasty FAST. If you feel like really going to town, some M5x12 bolts, also galvanised, to replace the bolts holding the solenoid and OPV on may also help you give it that full restoration feeling.

Also recommended: new shower screen, caffiza to soak your portafilter and distribution plate in, and some decalc of your choice, either Gaggia's own Decalcificante or Puly Caff.


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## DRAXXMENVONE (Jun 19, 2018)

Many thanks folks. Already have the full gasket kit. Hadn't considered the bolts. I'll have a look at them when I open it up. More as it happens!

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## DRAXXMENVONE (Jun 19, 2018)

Got this kit

https://www.ebay.co.uk/itm/223958642049


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## worzel (Apr 9, 2020)

allikat said:


> Replacement gaskets and o rings are a must. If your machine is over 10 years old, then replacement boiler bolts are strongly recommended. M6x16 galvanised is what you need. They're zinc coated steel bolts holding an aluminium boiler to a brass brew head, and when they rust, they go nasty FAST. If you feel like really going to town, some M5x12 bolts, also galvanised, to replace the bolts holding the solenoid and OPV on may also help you give it that full restoration feeling.
> Also recommended: new shower screen, caffiza to soak your portafilter and distribution plate in, and some decalc of your choice, either Gaggia's own Decalcificante or Puly Caff.


I dropped my boiler bolts in the Puly cleaner by mistake and they came out black. Are they ok like this or has the coating been stripped?

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## Skizz (Feb 10, 2020)

Can only speak from my own experience of rebuilding a 2004 Classic (others have far more experiece than me):

As you'll have the machine apart you may as well replace ALL the seals and gaskets. Go with silicone where you can, especially for the grouphead-to-boiler interface and grouphead gasket. Be prepared to do some sanding and polishing on the mating surface if they're scaled up.

Also, use stainless bolts not galved. Stainless fasteners on aluminium castings are fine and you won't have to worry about them frying if you get a slow leak you don't find for a while.

Have a look at the dispersion block and shower screen too as they may need replacing on an older machine. Also, order yourself a £12 portafilter pressure gauge off ebay, that way you can check the OPV and adjust if needed.

The video linked earlier in this thread is a good starting point.

I suppose the only other things to consider are whether you want to fit a PID while you've got the thing in bits. And maybe swap the steam wand out for a Silvia V1/2?

The thread on my rebuild and mods is here if it's any help: rebuilding & modding a 2004 Classic

There's a stack of experience working on these machines in the forum so you're in good hands!

Have fun


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## Matt D (Apr 13, 2020)

Hi ,

I just completed by rebuild based on the above youtube video - I now have a transformed machine

A few points I learnt

1/ Its worth taking the OPV apart .

2/ Blind set the opv at 130ml per 30 seconds is a good starting point if you don't want to invest in a pressure gauge

3/ I went for the tablespoon per litre of citric acid - but needed 3 soakes to clean to boiler

4/ Lower pressure has meant a finer grind is needed .

5/ I numbered everything that moved !

Good luck

Cheers,

Matt

https://www.coffeeforums.co.uk/topic/50982-gaggia-classic-pre-2015-opv-blockage/?do=embed


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## DRAXXMENVONE (Jun 19, 2018)

Skizz said:


> Can only speak from my own experience of rebuilding a 2004 Classic (others have far more experiece than me):
> As you'll have the machine apart you may as well replace ALL the seals and gaskets. Go with silicone where you can, especially for the grouphead-to-boiler interface and grouphead gasket. Be prepared to do some sanding and polishing on the mating surface if they're scaled up.
> Also, use stainless bolts not galved. Stainless fasteners on aluminium castings are fine and you won't have to worry about them frying if you get a slow leak you don't find for a while.
> Have a look at the dispersion block and shower screen too as they may need replacing on an older machine. Also, order yourself a £12 portafilter pressure gauge off ebay, that way you can check the OPV and adjust if needed.
> ...


Thanks. Very helpful. Don't think I'd go for a PID. I'm upgrading the wand. I've been pretty happy with the shots my other work Classic produces. I'm actually fixing this one up in order to sell my Rancillio Silvia which I'm not getting on with. Ultimate aim is to get hold of a used Lelit Mara.

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## DRAXXMENVONE (Jun 19, 2018)

Matt D said:


> Hi ,
> I just completed by rebuild based on the above youtube video - I now have a transformed machine
> A few points I learnt
> 1/ Its worth taking the OPV apart .
> ...


Many thanks. I do have a pressure gauge knocking around somewhere. I'll dig it out.









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## allikat (Jan 27, 2020)

worzel said:


> I dropped my boiler bolts in the Puly cleaner by mistake and they came out black. Are they ok like this or has the coating been stripped?
> 
> Sent from my iPhone using Tapatalk


 If they look fine, they'll be ok for a year or 2, but not longer as the zinc coating is important. Replace them, either now, or after a fight to get one or more out next time you have to open the boiler.



Skizz said:


> Can only speak from my own experience of rebuilding a 2004 Classic (others have far more experiece than me):
> 
> As you'll have the machine apart you may as well replace ALL the seals and gaskets. Go with silicone where you can, especially for the grouphead-to-boiler interface and grouphead gasket. Be prepared to do some sanding and polishing on the mating surface if they're scaled up.
> 
> ...


 Galved is fine, it's what's specced in the original part list. If you wish to use stainless then I can see no issue.

I second replacing the shower screen, the dispersion block should be fine with a soak in caffiza or the like. Mine just got scraped and scrubbed clean on my 2001 Baby.


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## DRAXXMENVONE (Jun 19, 2018)

Sorry. How many of these bolts do I need? I want to get all the bits before I begin. Also, are any specialist tools beyond Allen keys, screwdrivers and spanners needed?

I'm going to try to reuse most parts like shower screen and dispersion plate if I can. There was no problem with the shots before the thing became horribly leaky.

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## allikat (Jan 27, 2020)

4 for the boiler. 4 of the smaller ones if you're doing the valve bolt replacements too. And you may want or need a hammer and a spikey thing. The hammer will help encourage the dispersion plate loose as it can get a bit stuck in with coffee oil that turns to glue given enough time. The spikey thing is to remove the brew group gasket if it doesn't easily come loose when the dispersion plate is removed. Just wreck the old gasket if you have to, you have a replacement.


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## Nickh1977 (Apr 13, 2020)

I'm torn between a new sage machine and a a second hand classic, but always worried about condition of second hand machines. The video gives me a bit more confident about stripping and servicing a classic, thanks very much, I'm being swayed.


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## Skizz (Feb 10, 2020)

allikat said:


> 4 for the boiler. 4 of the smaller ones if you're doing the valve bolt replacements too.


 Just be careful as some suppliers send bolts for the group head to boiler interface that are too long. The ones I had from the Espresso Shop were 2-4mm too long (cant remember which) and had to cut them shorter. Not difficult with two nuts locked against each other to cut against but a faff nonetheless. And they were stainless, which I think most people supply as standard now anyway 😉



> And you may want or need a hammer and a spikey thing. The hammer will help encourage the dispersion plate loose as it can get a bit stuck in with coffee oil that turns to glue given enough time. The spikey thing is to remove the brew group gasket if it doesn't easily come loose when the dispersion plate is removed. Just wreck the old gasket if you have to, you have a replacement.


 The group head is brass, so relatively soft and quite easy to damage if you go clouting things with hammers and chisels/drivers etc. Instead, use a longer bolt of the same gauge as the screen holder screw, thread it into the screen-screw hole on the dispersion block and it'll drive the dispersion block off the group head.

Also, If the grouphead is reluctant to separate from the boiler you can tap Stanley knife blades into the join to ease them apart.

Finally, if the old group head gasket doesn't want to come out then you can drive a screw into it and use pliers to lever it out. If its that knackered it'll probably come out in chunks but once the first bit lets go the rest are easier. Remember to put something between the pliers and the group head when levering though, as again, its easy to mark the brass.

As a general rule, take your time and be prepared to soak stuff in descaler for longer than you're expecting.


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## allikat (Jan 27, 2020)

I didn't go to an espresso shop for mine, I bought a pack of 10 bolts from a regular hardware supplier. Perfect size.


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## Skizz (Feb 10, 2020)

allikat said:


> I didn't go to an espresso shop for mine, I bought a pack of 10 bolts from a regular hardware supplier. Perfect size.


 I'd have done the same (and paid a fraction the price) but was stuck at home for a week waiting on deliveries of building materials and wanted to get started. Was a bit narked when I realised I had to cut down the bolts I'd already paid over the odds for. Prompted me to top up my stash of M5 and M6 bolts though so won't get caught out again.


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## DRAXXMENVONE (Jun 19, 2018)

Hey folks. So totally stripped it down and I've been soaking the boiler in increasingly strong citric acid solutions. Still some scale as shown. Is there a way to manually remove the scale without damaging the boiler?



















Here's what it originally looked like:










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## Oli986 (Apr 24, 2020)

I recently rebuilt my Gaggia Classic. My boiler was in a similar condition, I used a small fairly soft wire brush & some wire wool to get rid of as much stubborn scale as possible. I don't know if there's any issues with that method but I've had no problems.


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## Skizz (Feb 10, 2020)

Similar approach to @Oli986, I used a small brass-bristled brush and an engineers scribe to shift the more stubborn bits of scale.

Go easy on the grouphead though as too much citric acid and elbow grease will take the chrome off it. Make sure you strip the solenoid diverter assembly and take the o-rings out of the OPV and solenoid manifolds before soaking. The o-rings will need replacing anyway and the diverter rubber inner bits (technical term I made up) can harden in highly acidic solutions.


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## Oli986 (Apr 24, 2020)

Skizz said:


> Similar approach to @Oli986, I used a small brass-bristled brush and an engineers scribe to shift the more stubborn bits of scale.
> 
> Go easy on the grouphead though as too much citric acid and elbow grease will take the chrome off it. Make sure you strip the solenoid diverter assembly and take the o-rings out of the OPV and solenoid manifolds before soaking. The o-rings will need replacing anyway and the diverter rubber inner bits (technical term I made up) can harden in highly acidic solutions.


 I left my solonoid assembly out of the descaler as that video warned about what you just said. I gave it a good clean with hot soapy water, but didn't realise you could remove the rubbers. Tbf I was being very cautious


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## Skizz (Feb 10, 2020)

Good call 👍. Cafiza or Puly Caf will deal with the oil residues inside the diverter assembly so give that a go, and soak your PF, baskets, shower screen and dispersion block while you're at it.


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## Oli986 (Apr 24, 2020)

Am I right in thinking that when you descale normally and flush the machine through it doesn't pass through the solenoid?


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## Michael87 (Sep 20, 2019)

I need to do this soon... group is leaking a bit of steam since I descaled, and my OPV is behaving shall we say 'nonlinearly' when I turn the allen key...


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## Dave double bean (Mar 31, 2020)

Oli986 said:


> Am I right in thinking that when you descale normally and flush the machine through it doesn't pass through the solenoid?


Solenoid can be cleared with Cafiza and a blanking plate can't it?

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## DRAXXMENVONE (Jun 19, 2018)

Thanks team! Just went in there with a bottle brush and a screwdriver for the really awful bits. Fair amount of pitting inside I suspect due to citric acid through the years. Reassembled it and everything seems good.

Next question. Where can I get a steam wand upgrade for a good price. I bought one from amazon for £17 last year. They all seem to be much more pricey now.

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## Matt D (Apr 13, 2020)

I stripped the OPV to its component parts and then cleaned - made a huge difference


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## jaffro (Oct 6, 2015)

Matt D said:


> I stripped the OPV to its component parts and then cleaned - made a huge difference
> 
> View attachment 39596


 Nice.

I stripped my old one down a couple of weeks back. All looked fine at first glance... Until I opened up the boiler, not pretty! I ended up getting a second hand boiler off ebay to replace it.

I hadn't taken the OPV apart at all, but that's a really good idea. It was a bit stiff when I last adjusted it, so imagine it's worth cleaning out.


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