# Stuck bolts on Gaggia Classic boiler



## sambomartin (Jul 27, 2015)

Hi all,

This forum has been recommended to me by a fellow gaggia classic owner.

I've sadly neglected to change the gaskets and rubber washers on my machine for about 8 years. TBH i didn't know (until recently) that this was supposed to be a regular maintenance task. but i'm on the case now.

I've stripped everything back and got the boiler out, undone two of the bolts keeping the head on, but two are stuck. I'm guessing due to some rust on the other bolts they maybe corroded.

I'm hoping someone can recommend a solution to free these nuts. I've thought about chilling it and using wd40, but so far resisted temptation now hoping for some more experienced advice.

I've linked a picture of the problematic screws/bolts









Thanks in advance

Sam


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## mremanxx (Dec 30, 2014)

If memory serves the head is an alloy and the bolts will be seized due to the dissimilar metals, use a blow torch and gently heat the casing very gently, crack the bolts loose the re-tighten them slightly, this is to avoid warping


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## Dylan (Dec 5, 2011)

As you may have it round the house WD40 left to soak into the bolts for a few hours can be enough to free them

I stripped down a gaggia cubika a long time ago and remember these bolts being VERY tough to get out. I think I used a wrench with a long attachment and then tapping this with a hammer.


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## Thecatlinux (Mar 10, 2014)

Gentle persistence and good fitting Allen drive , aluminium can be quite unforgiving


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## timmyjj21 (May 10, 2015)

Ooh I love these ones!

I found that WD40 just can't penetrate enough. The corrosion is basically the lenght of the bolt going through the aluminium top part of the boiler and stops as soon as the thread goes into the chromed brass base. The build-up of calcium seems to stop anything penetrating well. You can use an Allen key with a long (hollow) metal bar over it to extend and provide leverage, but it may round out the hex socket of the bolt. If the bolt gets rounded out, I use a dremel and cutting disc to make a 3mm slot in the head to fit a lenght of 3mm steel bar and use it like a flat head screwdriver. This may rip off the head of the bolt. That's fine, because you can at least separate the boiler and the bolt remnants can then be unscrewed from the base with molegrips.

I don't know if you have access to these tools, but this is what has worked for me. A blow torch may give you good results if you can heat the aluminium to expand the hole and release the bolt.


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## El carajillo (Mar 16, 2013)

Remove the thermostats before applying any heat. Also remove / dig out the group seal. Take care where you apply heat as the "U" shaped channels on the outside of the boiler are the heating elements.

Brush or scrape off as much corrosion as you can to show the metal. Plus Gas is far more effective than WD 40 as it is specifically for freeing seized nuts and bolts, wrap some small pieces of rag around each bolt and spay with Plus Gas ( the rag retains more penetrating fluid )repeat this several times then try using a GOOD alan key, try a little tightening first the try undoing, continue applying penetrating fluid .


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## sambomartin (Jul 27, 2015)

Wow! thank you all. I will get wd40ing, blow torching and dremeling.

I've been careful not to round the hex too much, but given a fair bit of force, tapping, long bar for leverage etc. Two of them are really stuck.

Incidentally, do you happen to know where you can get replacement bolts? Doesn't seem right to reuse the rusty ones.

Also, I don't suppose you could tell me where the thermostats are?









Thanks again

Sam


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## timmyjj21 (May 10, 2015)

The thermostats are the black and brass things with the 2 wire attachments. Your photo has the brew thermostat pictured.

You can eBay new bolts, I recommend going stainless steel so you don't have this issue as badly next time.


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## Dylan (Dec 5, 2011)

Careful if you remove the thermostats, when you put them back in you want them barely more than finger tight. The Brass bolt that screws in is very easy to break off if over tightened.


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## MrShades (Jul 29, 2009)

I've had to use a good quality socket set (with hex drive impact socket) connected to a vertical extension bar (to get up above the boiler whilst keeping the socket vertical) and then a great big ratchet handle on the top to get good leverage.... and even then it can be a "challenge" to get the initial 'crack'.

I can also second the "use a Dremel to cut a slot in the top" approach - having done that also - and again used a socket set / large flatblade screwdriver socket with extension bar and ratchet handle on the top etc.

...and finally, yes, eBay for replacements - very cheap.


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## timmyjj21 (May 10, 2015)

Just checked, the boiler bolts are M6 x 16mm. Usually under £1.50 for 10 of them in stainless steel.


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## JohnPrime (Nov 2, 2014)

Use penetrating oil as above; however, rather than going all Arnie at it with a socket set, see if you can borrow a little impact driver (one of the Li battery jobbies, a bit like a miniature power drill). There'll be way less impulse (torque x time) applied to the fasteners and consequently much less chance of shearing or stripping.


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## gaggiamanualservice.com (Dec 22, 2009)

If the bolts shear, don't worry. The boiler is not threaded. You can then prize boiler off. Then use mole grips to remove the snapped off bolts. You will just need to source replacement bolts.


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## sambomartin (Jul 27, 2015)

Ok here's an update. Thanks again for for all comments.

It's amazing how many of these suggestions I ended up trying before I read the comment.

Id already tried a small drill with hex bit and extension on low torque to try and shudder the bolts out. It didn't work then I posted.

In the end I sprayed in wd40 and gently heated with blow torch. Came off no problem.

I've since cleaned everything up and reassembled machine. I have a problem with the stream valve now where it's leaking from the top of boiler.

The brass valve is quite soft and it was a nightmare to pry off. I guess I've scratched or damaged the flat bit? It's a new valve washer /gasket so can't be that? Any experience with this anyone?

Can I also double check that the boiler went back in not immaculate. I spent ages cleaning it with citric acid solution but still had some limescale residue.

Thanks again all

Sam


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## Kai (Feb 1, 2015)

I had the same issue with my Steam valve , after cleaning it would weep.

My solution was to wrap a little ptfe tape to seal the gap between the boiler and valve , it's worked perfectly


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## Dylan (Dec 5, 2011)

yup, ptfe tape, most of the seals/gaskets on my machine are just lots and lots of compressed ptfe tape. Works a treat.


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## sambomartin (Jul 27, 2015)

Just lay it between the valve and the top of boiler?


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## Dylan (Dec 5, 2011)

I assume there there is a thread of some sort?

You just wrap the ptfe around the top of the thread, quite thick and then it will compress as you screw down the valve.


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## timmyjj21 (May 10, 2015)

Interesting. The seal sits in the concave/ cone area of the hole in the aluminium boiler and seals against the flat part of the steam valve. I would check that the cone is smooth and if not, use some wet and dry sandpaper to get rid of any marks. If sanding, create circumferential lines...ie push paper down and twist it instead of rub back and forth, that way there are no radial grooves the steam can leak out from. Check the flat of the steam valve and do the same.


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## Syenitic (Dec 1, 2013)

Dylan said:


> yup, ptfe tape, most of the seals/gaskets on my machine are just lots and lots of compressed ptfe tape. Works a treat.


In an alternate career, and in my younger days I too was struck by the majik of PTFE thread tape....we backed off 2000psi Hydrogen cylinders at the regulator....worked on them...not even that gas could get by it...or maybe I was just very very lucky....

In a classic I am certain that is a good solution though..


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## El carajillo (Mar 16, 2013)

Rather than using sand paper, screw up the corner of a "pot scourer" and rotate this in the recess:good:


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## sambomartin (Jul 27, 2015)

Thanks. It's quite mashed up. Here's a pic. You think there is hope?


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## timmyjj21 (May 10, 2015)

No worries. The outer mashed edge is not overly important, just the central depression area. Try a pot scourer to get rid of the buld up of scale. If you are very careful, I have had success using a tiny flat jewlers screwdriver to gently chip the thicker deposits first and not mark the aluminium. I have finished it with wet and dry sandpaper, starting with 800 and going to 1500. You don't want to sand too much off, just polish!


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## El carajillo (Mar 16, 2013)

To clean the flat area where the bolt holes are, remove the T /stat and release the clip and move the plastic sleeve/ thermal fuse to one side. Carefully hold a flat file on the corroded area

( pressing centrally) then gently push the file across, repeat this several times to clean the area, do not remove too much.


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## Pippyd (Apr 7, 2017)

So far... 1 sheared and one head rounded on a 11 year old machine (with good hex heads) so this is good to hear! I'm waiting for new spare bolts before I go any further... because at least now I can still carry on making coffee ?



gaggiamanualservice.com said:


> If the bolts shear, don't worry. The boiler is not threaded. You can then prize boiler off. Then use mole grips to remove the snapped off bolts. You will just need to source replacement bolts.


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## El carajillo (Mar 16, 2013)

Wrap some small pieces of rag around each bolt, then dribble vinegar on the rag and leave to soak, repeat vinegar then try A / key again.

Vinegar penetrates more easily and helps dissolve the corrosion.


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