It's been a while since there has been any chatter on the Pedretti kim express espresso maker.
I've been interested in acquiring a spring assisted lever machine since my current machines are all of the full manual variety.
On a whim I pulled the plug on a complete machine. Big catch is that it came with a 220v, while my household voltage is 120v.
I decided to swap out the 220v element and currently in the process of replacing it with a 120v element.

A bit of a challenge remove the tight 36mm nut.
The big challenge was finding a 36mm socket. Third times a charm as I found one at a larger automotive \ multi wares store nearby.
After many tries a three foot pry bar, penetrating fluid and heat gun cycles on full I finally managed to remove the nut.
The element base became fused to the boiler body and required more penetrating fluid coupled with a lot of hammering with a large metal punch.

For those who have never see a Pedretti kim express element, here it is. F.Y.I. the foamy stuff is soap since the penetrate was quite oily,







On a lucky note this the Kim variety whereby the piston is removed easily from the top for cleaning or seal replacement.

redbone wrote:After many tries a three foot pry bar, penetrating fluid and heat gun cycles on full I finally managed to remove the nut.

FWIW, sustained application of serious force in this manner often causes breakage of either the threaded assembly or (more commonly) the metal to which it was secured by weld, braze etc. This is how so many boilers (and wheel studs, metal sheds etc with corroded fasteners) get bent or broken.

A power impact wrench applies the force repetitively but very briefly, so it's both much less likely to break anything (if set to deliver reasonable torque) and more likely to successfully loosen the offending junction. The heat, penetrant etc are all useful aids.

Although my IR air impact wrench is ideal, I've had and loved a B&D electric one for many years and use it for all non-automotive tasks. They're inexpensive and work great within their torque limits (eg it won't remove a 36mm flywheel nut).

I'm also a big believer in antiseize compound - just be sure it's food grade and temperature-safe. There are many kinds out there.

The Kim has a very robust body. The process of removing the element was slow and took the better part of the day waiting to see if the penetrating oil would assist here. The fused element was left overnight with penetrating fluid after some failed attempts.
No lower damage occurred to threads on either the boiler or element. As a test I was able to screw in both the element and nut.
Tight area to work within both in boiler and below due to element location deep in boiler body which also limited force.
All worked out. The real challenge is replacement with suitable element.
I use to have a impact gun but never replaced.

I agree with the recommendation of an impact wrench. Without one, I was advised when using penetrating oil to loosen parts to let it sit for days, if necessary, return to the part to tap it gently with a hammer or a tool that can extend the hammer's impact to the part. That's a good way to start. There's a Loctite food-safe anti-seize compound you should be able to find online. I use it wherever it is applicable, having gone through too many restoration experiences of freeing parts like this. I also hope to install a 220v outlet in my house so if I acquire a European voltage espresso machine, I don't need to trade out parts or rewire. Currently I have a version 1.0 Caravel with a working 220v element and working 110v too. I avoid using it, lacking a 220v outlet, because I don't want to go through rewiring or replacing the microswitch.

redbone wrote:The Kim has a very robust body. The process of removing the element was slow and took the better part of the day waiting to see if the penetrating oil would assist here. The fused element was left overnight with penetrating fluid after some failed attempts....All worked out.

You lucked out

Thousands of heat/cool cycles embrittle many of the metals commonly used in espresso machines, which is why so many here post about cracks and leaks - it doesn't take anything more than the vibration from the pump to propogate a crack over time. Applying a 3 foot breaker bar does the same thing in one fell swoop that normal use does over years (yes, I know that a lever machine has no pump - but the huge breaker bar will do in a few seconds what a vibrating pump does in a few years).

A day of penetrating agent isn't enough to reliably do the job on tough fasteners. When dismantling an old car, espresso machine, etc, my practice is to leave a container of penetrant next to it and apply a few drops to every threaded fastener that's not clean as a whistle every time I walk by (at least twice every 24 hours) for a few weeks.

Patience is truly a virtue, and it's amply rewarded - there's little need for repair of self-induced additional damage if you take your time and let your tools & chemicals do the same.

I've been working on a 1970 Pedretti Kim that past few months. My model was of the variety that allows the piston to be removed from the top.
The only issue was that my variant unfortunately came with a rare aluminum piston and either aluminum or pot metal spring which was pitted.
The group is has a decent brass sleeve pressed in the heavy aluminum body.
I was fortunate to find a 1971 brass piston and spring combo from who else but Francesco. Recently arrived in very good condition.

F.Y.I. I caution anyone who has this KIM piston \ spring combo that once removed you will need a large vice 8" minimum in order to compress this very strong spring and place lever back on.
I had to visit mechanic friend with 10" heavy duty table vice.

Expecting new element next week.

It is indeed a very strong spring, but I found that the challenge wasn't getting the spring back in with the 'remove from the top' types, as no compression should be needed with the install-from-the-top method. Maybe the spring and piston you got from Francesco was slightly longer? The challenge was getting the seals past the initial opening. It's quite a fight, even though they are the simple o-ring type and not u-cups. Once I got those in, the assembly essentially dropped into place.

Placing the spring \ piston back in the group was not the issue. The issue was trying to reassemble the spring \ piston back under the top plate.
This involves having to compress the piston enough for the rod to follow through the top plate and place the lever with pins back on through rod opening.

Here is a pic of the old aluminum one prior to disassembly.

Ah, gotcha - that makes sense now. Yes, that would be extraordinarily difficult with that crazy strong spring. Kind of amazing that Francesco had a spare for a relatively obscure machine - just goes to show how many vintage levers pass through his hands.

I was initially hesitant to ask him (Francesco) thinking that there would be no way he would have a specific part for a relatively obscure machine.
To my surprise I received a quick reply with decent pricing. He seems to have almost all parts minus elements for vintage single lever home machines.
I received a 1971 stamped piston in VG condition. Could not bear to place the pitted original piston / spring back into an otherwise very good condition machine.
The spring is much stronger than I anticipated. I'm about 194 lbs, my full weight on a wooden board on top of the spring maybe compressed it by 1mm.