Replacing the Elektra Microcasa a Leva spring

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
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IamOiman

Postby IamOiman » Jan 13, 2019, 3:56 pm

Hi HB,

I recently received my Elektra MCAL that I shipped myself from Italy, and have had issues dialing in my shots. I would be able to get nice extraction for the first 10 seconds, but at the halfway point of the lever rising it would slow and almost completely stop, leaving me with a horribly overextracted shot if I left it to completion. I decided to look online about it and concluded my spring for my Elektra, from 1991, is weak compared to its original strength. Looking at various forums, I decided to attempt to repair this through using the new spring (post 1997) and see what I can do with it.

I am creating a jig today/tomorrow to remove the old spring, and will include the following parts:

3/4" thick plywood
2 x 1/2" or 3/4" threads with washers and nuts
Dow 111 grease

I ordered my spring from Stefano through a friend who owed me the exact amount for the spring plus shipping.

Hopefully I will be able to begin testing of the new spring later this week and compare the results to prior attempts done by drgary and algue. I am not terribly interested right now in adding a second spring, but we'll see how this will turn out.

Here's the spring. Note in the second pic there is some slight corrosion that I will be cleaning once the spring comes off.

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-Ryan
I'll throw my portafilter in the ring
LMWDP #612

OldNuc

Postby OldNuc » Jan 13, 2019, 4:02 pm

DC111 is a very low film strength grease and as you can clean up the mess you make after it is all apart and back together using a full synthetic brake lube available at the auto parts will make the work much easier.

Sw1ssdude

Postby Sw1ssdude » Jan 13, 2019, 5:19 pm

Have you tried descaling the bore of the cylinder and regreasing, if not replacing the piston seals?
They look like they could use some TLC.
Use foodgrade silicon grease ('armature grease').
This might smoothen up the mechanism.

Springs dont get weak in my opinion, unless you stretch the spring from a disassembled ballpoint pen to the length of the pen itself when bored.

If the spring really is weak, you could use some spacers to get some more pretension. Just make sure the coils dont touch when compressed.

Be careful when working with springs, they can store tremendous amounts of energy. Small springs usually fly across the shop and land in the sawdust, never to be found again, big springs tend to hit you in the face. You do yourself a favor if you build a compression tool.

Good luck!
Lean Mean Caffeine Machine

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IamOiman

Postby IamOiman » Jan 13, 2019, 5:50 pm

Sw1ssdude wrote:
Be careful when working with springs, they can store tremendous amounts of energy. Small springs usually fly across the shop and land in the sawdust, never to be found again, big springs tend to hit you in the face. You do yourself a favor if you build a compression tool.

Good luck!


I will definitely take precaution. For my jig (which I will use for other small spring levers if I get them) I purchased 3/4" Plywood with 5/8" x 8" bolts with washers and nuts. I will be drilling the holes for the bolts and space for the spring later this week.

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@Oldnuc I purchased a silicone food safe grease based off the recommendation of the Lowe's employee (also they did not have Dow 111 anyways) that is normally used for faucets and plumbing.
-Ryan
I'll throw my portafilter in the ring
LMWDP #612

OldNuc

Postby OldNuc » Jan 13, 2019, 6:57 pm

With what you are doing, lubricating a bolt and nut, any grease would be good. Most food grade grease is just a poor performer for high pressure applications and the only way any of the grease on the bolts will get into the works would be almost intentional. hardware clerks are not experts on espresso machine disassembly and NSF-1 certifications. You probably mentioned food grade and that is what the clerk pulled off the shelf. If those bolts bind up on the washers and wood you will have a fight on your hands holding the bolt from rotating while you tighten the nuts to compress the spring. I would have a pair of vice grips handy to clamp on the bolt head while the nuts are cranked down. A wrench would work but will be prone to come off without warning and cause operator frustration.

The NSF-H1 certification is for incidental contact not proving to be toxic. Still not suggested to ingest any measurable quantity ever.

A set of silicone seals for that machine along with a new spring will do wonders.

Springs have definite cycle service life ratings so periodic replacement is an issue. Some springs have a cycle life down in the low thousand cycles, just depends on the quality and application.

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IamOiman

Postby IamOiman » Jan 14, 2019, 12:33 pm

I created my jig using tools provided by my Electrical Engineering department. I am pretty happy with it, and it should be able to hold my spring group as I compress it, which will be done later today after my classes.

I used a 1 7/8 inch hole saw and a 11/16 inch drill bit to create the hole for the group to fit through and allow me to remove the pin and a 5/8" bit for my bolts.

Even if I do not replace my spring now, I think it is good for me to have a jig to use in the potential future. I also want to clean my piston and spring separately.

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-Ryan
I'll throw my portafilter in the ring
LMWDP #612

OldNuc

Postby OldNuc » Jan 14, 2019, 2:27 pm

That will work just fine. One thing that can prove to be an issue is when there is not sufficient thread to allow removing all tension on the spring before you run out of thread. Must have enough room for the full uncompressed spring length and still have thread left over.

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IamOiman

Postby IamOiman » Jan 14, 2019, 4:06 pm

Got it off easily enough. I had more difficuly removing the lever pin than compressing the spring! I needed a separate pin and mallet to knock the other one out. I might try to remove the piston from the shaft but if it is not needed I will clean the piston and shaft together. I might remove the gaskets in this process too, but also only if I need to. Will citric acid affect any of these parts if left together?

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-Ryan
I'll throw my portafilter in the ring
LMWDP #612

OldNuc

Postby OldNuc » Jan 14, 2019, 4:13 pm

Hot/warm citric acid just over the piston would be about as far as I would go but it should not damage the rod either. Removing the piston may turn into a major undertaking, probably not a good idea without a good reason to do so.

Do you have new seals? They sometimes break when being removed.

I would polish those pins with #0000 steel wool and then relube with a real high pressure lube so the ware in the mating parts is minimized.

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IamOiman

Postby IamOiman » Jan 14, 2019, 4:41 pm

OldNuc wrote:Hot/warm citric acid just over the piston would be about as far as I would go but it should not damage the rod either. Removing the piston may turn into a major undertaking, probably not a good idea without a good reason to do so.

Do you have new seals? They sometimes break when being removed.


I do not have new seals, but can access them within 3-5 days if my current ones break. I left the piston and shaft together and stuck it in a citric acid solution in my 10oz coffee mug.
Image
-Ryan
I'll throw my portafilter in the ring
LMWDP #612