Bosco heating element leak has me stumped... - Page 2

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#11: Post by baldheadracing »

Just wondering - is there any issue with using NSF-rated pure Silicone sealant around the PTFE gasket to assure a good seal?

I realize that additional sealant isn't required if the mating surfaces are perfect, and that PTFE gaskets require proper torque - and also re-torquing after a few heat cycles. However, I have always used Silicone as insurance on the machines that I have had apart. Is there an issue with that practice?
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#12: Post by JohnB. »

sheedapistawl wrote:Plan to message bosco as well, thank you all for weighing in!

I am inclined to try more torque with my 12" knipex, covered with insulation tape on the teeth to prevent marring, and hand on boiler to brace to not cause any stress elsewhere while torquing, and then t try hot / cold cycles of tightening until leak goes away.

Thoughts on sanding off the oxidation layer on the lid where the gasket seats? Was thinking light wet sanding 150,400,1000, 2000.
A red 3m scuff pad should clean up the gasket surface. A light coat of well mixed Rectorseal #5 on the sealing surfaces may help seal it up if you can't apply the torque required to fully seat the bare gasket.

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#13: Post by ira »

Find someone with an impact, now that they come battery operated, lots of people have them. It really is the right answer.

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#14: Post by mrgnomer »

That or you could try the right socket size on a breaker bar. Works for corroded on lug bolts. I don't think channel locks would give you enough leverage if the solution is more torque.

You'd have to clamp the boiler down to keep it from moving. A strap wrench might help along with an extra pair of hands.

In the end, though, impact wrench is probably the best option. Some have taken their boilers to auto shops for help getting elements off. Give them a torque spec and they should be able to help tighten an element on.
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#15: Post by Paul_Pratt »

If it leaks just when it is not under pressure the gasket is not squished at all. Since the actual mating surface looks somewhat ok I would guess that something is preventing the teflon seal from seating correctly. Without a gasket, does the element screw in all the way and butt up against the boiler end plate?

Don't be afraid to use teflon tape on the threads, many manufacturers use tape and a gasket. I would order a new boiler end plate gasket too and when it arrives do both. You could get lucky and reuse the old plate gasket, but better to have a spare on hand.

A long shot - from the photo maybe the recessed part of plate where the gasket sits has a bit of a lip to it on the bottom. The seal is getting stuck on that lip. You can also centre the teflon seal before you tighten it down. You really should not need an impact for this, teflon is very squishy. I would guess the seal is being prevented from seating by something.

It is also quite unusual for the seal surface to be plain flat. It is usual to have some annular grooves to help with sealing and it also helps prevent the teflon creeping outwards.

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#16: Post by JohnB. »

Paul_Pratt wrote:Don't be afraid to use teflon tape on the threads, many manufacturers use tape and a gasket. I would order a new boiler end plate gasket too and when it arrives do both. You could get lucky and reuse the old plate gasket, but better to have a spare on hand.
The boiler cover seals with a large o'ring.

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#17: Post by IamOiman »

The new ones no longer use the o ring. My 2018 Bosco has that style but in 2019 they started using a fiber gasket. The easy way to check is to see the different boiler lid design where the bolt threads are blind holes. Sheeda's lid looks sussy enough to consider changing out the gasket in my opinion, especially with the residue exuding from the bolts

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#18: Post by Paul_Pratt »

JohnB. wrote:The boiler cover seals with a large o'ring.
You can see a flat gasket in the photo. If they did not use sealant you can usually reuse it. If they used sealant then it will probably be stuck and will break apart. But then again if they used sealant it would probably not be leaking.

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#19: Post by JohnB. »

Good to know, I didn't realize they had changed the design. Of course since it's leaking after just 2 years I don't know if I'd consider it an improvement. 12 years on my boiler o'ring and counting.

sheedapistawl (original poster)

#20: Post by sheedapistawl (original poster) »

Thank you all!!

So I sanded the enclosure where the gasket sits 150>400>1000>2000 and got it real smooth, then torqued while bracing the boiler with my hand

At temp and pressure, no more leak at the element!!

A few questions to close this out for now:

(1) I suppose we are good with this for now for the element at least? Or should I attempt to tighten more after machine is heated (ie turnoff wait to cool a bit and tighten)

(2) the color around the boiler nuts and the shape of the boiler gasket, should I use it until something happens or proactively replace it? Plan to ask bosco too but when I sent them a video and photos from the top they just said element gasket... maybe once they see it they can tell me

(3) just in case the boiler gasket needs replacement... is there any world where it can be done with the boiler on the machine :'( the thought of disconnecting and reconnecting so many fittings is intimidating

(4) earth mount corrosion... it's possibly due to wet cups being put on top, but could their be another reason? That would also explain the scale. We wash with tap water and sometimes place above it. If not the wet cups dripping... could that be something unrelated?

I am hoping someone says don't worry just use the machine it's all good :cry: