(Another) Sleeve stuck on piston

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Balthazar_B

#1: Post by Balthazar_B »

EDIT: Solved that problem, described on page 3. But now I have another. :(

EDIT 2: Second problem solved. Wrap up on page 4.

In case you're feeling a little deja vu, it's because someone else was having a similar problem several weeks back. I think his case was complicated by his spring being compressed. But anyway, my piston started slipping a little during pulls, and so I decided to check the seals and apply some lube. But when I pulled the piston from the machine this time, the sleeve came with it, firmly stuck to the piston.



I used a heat gun on the sleeve to see if that would loosen up the seals, but no dice from applying much elbow grease afterwards. Hoping for some suggestions on freeing up the sleeve. Without damaging it!!

Thanks, all!
- John

LMWDP # 577

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pizzaman383
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#2: Post by pizzaman383 »

I had it happen to mine again, today.

Basically, I pull the lever to compress the spring and move the piston up in the sleeve. Doing that while the sleeve is in the group is safest way.

Then I clamp the sleeve in a vise. If you have a wood or plastic jaw vise then it doesn't matter where you clamp the sleeve. If you only have a metal jaw vise then you need to stay away from the places where the seals seat. There is a slot in which a rubber seal sits so that is easy to see. The other seal sits in a similar groove in the group and slides on the smooth outside surface of the sleeve at the sleeve's bottom so stay away from that (the left end of the sleeve in your picture). The wide open section towards the right side of the sleeve in your picture.

Once I have the sleeve clamped or held securely I pull the spring head out with steady pressure and slight back and forth wiggles. Don't wiggle enough that the piston hits the side of the sleeve - just enough to have it move outward as you pull the piston assembly out.
Curtis
LMWDP #551
“Taste every shot before adding milk!”

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JohnB.
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#3: Post by JohnB. »

Is that corrosion/mineral deposits on the water path area of the sleeve?
LMWDP 267

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Balthazar_B (original poster)

#4: Post by Balthazar_B (original poster) » replying to JohnB. »

No, it's Loxeal. I just didn't clean it off before posting the pic. There is no evident scale or other deposits on the sleeve, screen, or grouphead, all of which are exceptionally clean.
- John

LMWDP # 577

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Balthazar_B (original poster)

#5: Post by Balthazar_B (original poster) »

So noodling on pizzaman/Curtis's solution, I'm wondering whether a variation on that might work:
  • First, secure the sleeve in a vise in a way that won't mar or misshape it. Thinking about what Curtis calls the wide open section between the two flared sections (top and O-ring).
  • Instead of pulling the spring head out, how about using a wide wooden dowel with a hammer to applly very light repetitive taps and gradually push the piston out from the bottom? This will require someone holding on to the spring/head to ensure it doesn't fall, of course.
  • It just seems inherently safer to do it this way than risking torquing the piston which might cause it to mar the sleeve.
I know the piston is not in its usual "dead" position in the sleeve...it moved up at least a couple centimeters from there. It just doesn't want to go further with any amount of twisting and turning.

Any reasons why the above would be a stupid idea?
- John

LMWDP # 577

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JohnB.
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#6: Post by JohnB. »

I removed the sleeve intentional recently while trying to sort a low shot temp issue. After reinstalling it & the piston assy. I had to pull the piston assy out again to check something. This time the sleeve came out with it & looked pretty much like your photo. I held the sleeve with my hand & locked down the lever, then released it. This moved the piston up in the sleeve far enough so that I could wiggle it out. Be very careful of the sleeve o'ring unless you have spares. I couldn't find a supplier in the U.S. & Bosco is having supply chain issues due to Covid. I placed a parts order with Roberta on 1/12 & they won't be getting them until later this week.
LMWDP 267

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Balthazar_B (original poster)

#7: Post by Balthazar_B (original poster) »

JohnB. wrote: Be very careful of the sleeve o'ring unless you have spares. I couldn't find a supplier in the U.S. & Bosco is having supply chain issues due to Covid. I placed a parts order with Roberta on 1/12 & they won't be getting them until later this week.
Hey, John, thanks for the heads up on the O-ring. I've been very careful with it, and Bosco did include a spare with a seal replacement kit I have. Guess this would be a good time to put in an order as well. I'll take my calipers to it, but do you happen to have its official specs?
- John

LMWDP # 577

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pizzaman383
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#8: Post by pizzaman383 »

Balthazar_B wrote:So noodling on pizzaman/Curtis's solution, I'm wondering whether a variation on that might work:
  • First, secure the sleeve in a vise in a way that won't mar or misshape it. Thinking about what Curtis calls the wide open section between the two flared sections (top and O-ring).
  • Instead of pulling the spring head out, how about using a wide wooden dowel with a hammer to applly very light repetitive taps and gradually push the piston out from the bottom? This will require someone holding on to the spring/head to ensure it doesn't fall, of course.
  • It just seems inherently safer to do it this way than risking torquing the piston which might cause it to mar the sleeve.
I know the piston is not in its usual "dead" position in the sleeve...it moved up at least a couple centimeters from there. It just doesn't want to go further with any amount of twisting and turning.

Any reasons why the above would be a stupid idea?
I think that might work but I thought of that as my second option to use if I could not pull it out by hand.

I inspected the chromed inner surface of the sleeve and noticed some buildup of material. It must have been some combination of lubricant and seal material that was plating the surface. I used alcohol and paper towels to remove it (not easy). You might want to check for this.

I have used three types of seals and two kinds of lubricant so not sure what caused it.
Curtis
LMWDP #551
“Taste every shot before adding milk!”

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JohnB.
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#9: Post by JohnB. »

Balthazar_B wrote:Hey, John, thanks for the heads up on the O-ring. I've been very careful with it, and Bosco did include a spare with a seal replacement kit I have. Guess this would be a good time to put in an order as well. I'll take my calipers to it, but do you happen to have its official specs?
There are 2 different sleeve o'rings. Use the following part numbers when ordering from Roberta:

Black Upper sleeve o'ring #R210 (mounts on sleeve)
Red Lower sleeve o'ring #R215 (sets in the groove on group casting just above the group pf seal area)
Brown Flange O'ring #R240 (goes between 4 bolt group flange & reservoir casting)

Be very careful if you clamp the sleeve in a vice. It's thin & brass; easily cracked or distorted.
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JohnB.
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#10: Post by JohnB. »

Based on my recent experience & Roberta's advice I'd suggest removing the group casting from the machine every couple years & inspecting the water flow areas from the reservoir through to the inner group.

Found this when I removed my group recently:


Since I keep my coffeebar water in the 40-45 ppm hardness range I was surprised to see this. Especially since the boiler & heating element had no build up. Pulled the flow control valve/seat & found the passage opening between the valve & sleeve was 25% blocked on the valve side. There was also mineral buildup inside the sleeve on the group body where the water flows through. Soaked all the group parts in undiluted white vinegar for several hours & cleaned up the reservoir/flange area by brushing on vinegar & scrubbing with a 3m scuff pad.

Since I bought this machine used in 2014 I have no idea what water was run through it the first 3 years. Maybe this started back then & slowly built up. We'll see as I plan to inspect these areas in a year to see if there is any new buildup.
LMWDP 267