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Thread: Rancilio L4 rebuild (maybe)

  1. #1
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    Rancilio L4 rebuild (maybe)

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    I've purchased an old Rancilio L4 as a second machine and a rebuild project. The previous long-term owner is here on CS somewhere, so hello if you're reading! I'm the third owner.

    While I've rebuilt a commercial grinder, but this will be my first espresso machine. The L4 looks like a pretty straight-forward machine so hopefully, touch wood, it'll be a gentle introduction. And not too many tears will be shed if it goes totally pear-shaped.

    The machine was sold as a going-concern and it theoretically works (boy does she steam!). There are a few things wrong, some of which I knew about before purchase, but most of which I've discovered post-purchase. So now I'm weighing-up the value of proceeding.

    * The sight glass kind of works now and again. Probably some fouling in the pipes between the sight glass and the boiler. I'm thinking this means I should take apart the boiler and all copper lines and do a proper clean out.
    * The grouphead three-way valve is not bleeding to the drip tray. The previous owner said they regularly backflushed ... but it seems no avail.
    * More a curiosity than a problem ... the double portafilter spout had the spout offset pointing the wrong way. I suspect the spout might have been an aftermarket purchase. Easy to fix with a shim.
    * Moderate rust on internal panels and frame, bad rust on one panel, prior leaks. Frame and panels will need sanding/stripping and repainting or powdercoating.

    But the main mystery is the plumbing just after the vibration pump. The attached pic is *not* my machine - it is from another CSer - but I've used it to identify some missing pieces on mine. The pressure switch for low-water (blue) is completely missing in my machine, but I've seen photos of other L4s without it so I'm guessing that was a difference between versions - probably not an issue(?) The braided high pressure line (green) is actually a piece of ryco rubber automotive hose in my machine (mmm, tasty ) so that will need to go. And what looks like the OPV (orange) is missing altogether in my machine. So my machine has no way to bleed water back into the water tank. The attached rancilio parts drawings show both the pressure switch (#37) and OPV (#58).

    So I'm just wondering now whether the OPV (#58) is strictly needed. There is a device (#49 and friends) just upstream of the boiler fill solenoid (#48) which *is* present in my machine (hooray) on the line which runs into the middle of the boiler, which I think is the HX inlet. I don't know for sure what #49 does, because I can't find a part description for it. I'm wondering whether it is just a one-way valve, or if it prevents flow into the HX until a minimum pump pressure is reached so as to avoid water pushing towards the group during boiler fill. Or is it a max pressure limiter, which controls the group pressure during brew? If the latter, then I'm wondering if the OPV is really needed, other than to preserve the life of the pump? If the former, then so begins a search to find the right OPV and braided hose for a ye olde L4 :/
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    Last edited by rustyfence; 20th October 2019 at 12:00 AM.
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  2. #2
    Senior Member Sullo's Avatar
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    while I cant directly answer your question I can say from past experience of rebuilding only three machines, your best bet is to clean out all plumbing with citric acid on the brass bits, youll be amazed at the amount of crud youll get out of them. If its an old machine your also worth your while to replace most of the seals esp group head (is it e61? rebuild that too heaps of vids online for that) and steam wands.
    Good luck with the project, you going to do a rebuild post for it?

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    Thanks Sullo. No, is not an E61 - is a Rancilio proprietary group. I do have a new group seal though. I think I'll take your advice and give everything a good clean out first, before worrying about new parts - just in case in case there's something unservicable that I can't get replacements for.

    I think the element is the main component that might(?) no longer be manufactured, but it is definitely still working for now.

    I'll post pictures of the rebuild once I properly get started
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  4. #4
    Mal Dimal's Avatar
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    A new element would be the least of your worries I think.
    Lots of standard types abound that would be able to fit the boiler, just a matter of dimensions and output.

    Mal.
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  5. #5
    Senior Member level3ninja's Avatar
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    And worst case there are companies around that make custom elements (e.g. Hotco in Sydney)
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    Thanks, good to know the element won't be a showstopper if it dies ... it is bottom mounted and a bit unique amongst the Rancilios so would probably be a custom job.

    I've attempted to sign up to the Rancilio support portal to see if I can get some tech drawings and part numbers for the missing bits. I emailed them a week ago requesting a login account, but they haven't responded ... Has anyone here had luck singing up to their support portal?

  7. #7
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    OK, so I've had a bit of a poke around and removed the steam wand and hot water assembly for a quick look see.

    Ugh, even the hot water wand components were badly calced and stuck fast. After a 24 hour soak in an acid bath, and some serious coaxing, and I was able to get the old-style hot water spout and jet-breaker unscrewed and off the gimbal piece. Not before breaking some of the jet-breaker thread and having to re-tap new threads, though. The 30-year old fibre gaskets are stuck hard on the wand nuts, and very difficult to remove even after soaking.

    A few questions for old hands:
    (1) I'm going to need quite a few new washers, o-rings, fibre gaskets, copper gaskets etc. Is there a recommended supplier where I can get a box full of the usual suspects, rather than ordering them one-by-one?
    (2) What's the best method for removing little fibre gaskets/seals without gouging the brass seating surfaces? Automotive gasket remover spray?
    (3) How well do old copper compression fittings typically reseal when reassembled? Should I teflon tape as a precaution, or go raw and tape the leaking fittings only?
    (4) Is it usual practice to replace old boiler overpressure safety valves, rather than refurbish them?

    And I found the parts list (multilingual!). I've attached it in case anyone else needs it down the track...
    Attached Files Attached Files
    Last edited by rustyfence; 27th October 2019 at 08:08 PM.
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  8. #8
    Super Moderator Javaphile's Avatar
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    Manual copied to the Documentation area with a nod to rustyfence for it.


    Java "File herder" phile
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    Toys! I must have new toys!!!

  9. #9
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    Quote Originally Posted by rustyfence View Post
    (3) How well do old copper compression fittings typically reseal when reassembled? Should I teflon tape as a precaution, or go raw and tape the leaking fittings only?
    (4) Is it usual practice to replace old boiler overpressure safety valves, rather than refurbish them?
    DON'T be tempted to use teflon tape, and never use sealant or tape on any compression fitting unless there is no other option. They are designed to seal/reseal with only metal-to-metal contact, and I rarely have leaking issues with these type of joints on older machines.

    DON'T rebuild a boiler safety valve - they aren't rebuildable anyway, and you can't reliably 'set' the opening pressure yourself either. It is important for them to open at a precise pressure to work as a safety feature, which is why they are often fitted with seals to show they have not been tampered with. It is important enough for them to be factory calibrated that they often come from suppliers with a 'safety certificate' to verify they are set correctly.

  10. #10
    Senior Member Lyrebird's Avatar
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    Quote Originally Posted by rustyfence View Post

    (3) How well do old copper compression fittings typically reseal when reassembled? Should I teflon tape as a precaution, or go raw and tape the leaking fittings only?
    Depends on how they've been treated. One possible problem is that they can work harden and crack after a few assembly / disassembly cycles. You can get around this by annealing them: heat the flared end to red hot in a gas flame and plunge it into cold water. Easier with a gas axe but I've done smaller objects on a gas cooktop.

    I strongly agree with Morgan above: never use teflon tape on anything but the tapered fittings for which it was intended.
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