Re-gasket Bosco Sorrento

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def
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#1: Post by def »

After about 2 1/2 years of daily use, I could tell that my Bosco was in need of a gasket greasing because it required two hands to pull the lever -- one to prevent the machine from tipping over, and one on the lever. That means there was too much friction between the piston and the sleeve. It also means that my shots were taking longer because the pressure exerted on the water and coffee puck was lower. About a month ago, I pulled the lever down and it was much easier to pull than the day (and several months) before. So I removed the piston spring assembly which revealed that the top gasket had broken into several pieces. I did not have a spare gasket on hand, so I removed the pieces, greased with Dow Molycote 111, and put it back together with just 3 of the 4 silicon gaskets. This worked fine for a couple of weeks while I waited for new gaskets to arrive. I purchased a set of OEM silicone gaskets from Caffe Lusso which are $12.00 each, and a set from EspressoParts.com which are the blue silicone gaskets supplied by Cafelat for $5 each. Initially I was not planning to buy the OEM gaskets because the Cafelat gaskets always worked well in my Profitec Pro 800, but I was unsure whether they would work as well as the OEM gaskets so I bought both.

I decided to install the dark red OEM gaskets, and wow these are very stiff and difficult to get out and in. I used a bamboo chopstick to lever the old ones out and the new ones in. I greased the gaskets and put the group head back together. All went well for the first day, but then I noticed that the group head made a squeaking noise which sounded like the gaskets needed to be greased again. The piston was so difficult to remove that I ended up pulling the sleeve and the piston out together. After carefully removing the sleeve from the piston, I decided to replace the OEM with Cafelat gaskets which can be installed quite easily with bare hands.

After a few days of use, the Cafelat piston gaskets make no noise and the pulls are one-handed like they should be. It is early to make a confident conclusion, but the machine is operating optimally again, so I feel the Cafelat piston gaskets work at least as well as the OEM, and they are less expensive and easier to install/remove.

BSdV
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#2: Post by BSdV »

I expect the cafelat seals to be at least on par with the vast majority of OEM seals. They're made from silicon rubber which is much more flexible and able to handle much higher temperatures than many other types of rubber. They don't get brittle in time like the more common rubbers do. Judging by the smell of the pro800 OEM seals these are made from NBR rubber. I consider silicon rubber far superior to NBR for this use. In my Pro 800 I do lubricate the cafelat seals from time to time, but after more than 6 months of multiple times daily use I've never had to grease the lip seal in my Robot. Or at least never had the feeling I needed to grease the seal.

bettysnephew
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#3: Post by bettysnephew »

@def
Thanks for the info regarding the Cafelat seals. I still have a set of original seals I purchased when I ordered my machine. I will try the silicon seals the next time I order new seals.
BN
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JohnB.
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#4: Post by JohnB. »

Def - Was the top seal that hardened and broke a red silicone seal or the black rubber seal they used to use up top? I pulled my lever assy out today to lube the seals. I'm still using the 3 silicone/1 rubber set up and after 4 years all were soft and pliable. Do you leave your machine on 24/7 or have it on a timer?
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def (original poster)
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#5: Post by def (original poster) »

The seal that broke was a red silicone gasket -- all of the seals that came with the machine were the brick red type I assume are silicone, but they feel less pliable than the Cafelat seals.

My machine runs every day for 7 1/2 hours.

The broken seal is no big deal, but the bigger problem to me is this discussion about the OEM seals requiring Loxeal #4 grease and do not work well with Dow 111 molykote. My belief is that the OEM seals fit too tight in the sleave.

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JohnB.
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#6: Post by JohnB. »

def wrote: The broken seal is no big deal, but the bigger problem to me is this discussion about the OEM seals requiring Loxeal #4 grease and do not work well with Dow 111 molykote. My belief is that the OEM seals fit too tight in the sleave.
I've used nothing but Molykote 111 on the oem silicone seals for years with no problems. I've also never had any issues installing or removing them. What makes you think they require Loxeal #4? Bosco uses it because that's the most common silicone grease in Europe. I've had no problem going 12-15 months between relubing with the Molykote.
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def (original poster)
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#7: Post by def (original poster) »

I don't know that they require Loxeal but this was brought up by IamOiman ... something about after six months of Dow 111 he needed to regrease. So he tried Loxeal which is what Bosco uses. Also, two days after I installed the replacement OEM seals, the piston was squeaking and its movement was restricted. I'm not going to go down the road of buying expensive grease from Europe because frankly the Cafelat seals work better in my Bosco.

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IamOiman
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#8: Post by IamOiman »

I had issues with Dow 111 in my newer Bosco, to the point I was applying it monthly. With the Loxeal 4 it lasts almost a year but it's definitely not an issue John has experienced in his circa 2011 model. I've talked about it a lot in my Unboxing Bosco thread but whatever works best for you for the cheapest price is perfectly fine
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JohnB.
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#9: Post by JohnB. »

def wrote:I don't know that they require Loxeal but this was brought up by IamOiman ... something about after six months of Dow 111 he needed to regrease. So he tried Loxeal which is what Bosco uses. Also, two days after I installed the replacement OEM seals, the piston was squeaking and its movement was restricted. I'm not going to go down the road of buying expensive grease from Europe because frankly the Cafelat seals work better in my Bosco.
The Bosco seals worked fine in your machine for 2.5 years according to your original post. Now they only work for 2 days? What do you think changed?
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def (original poster)
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#10: Post by def (original poster) »

Good question; I don't know. Perhaps I did not apply sufficient grease, and/or perhaps they need some time to conform. The OEM replacement seals looked and felt identical to the original seals. The original seals were difficult to remove, and the replacements were difficult to install and remove. I broke one of the replacement seals upon removing it with a bamboo chopstick. Upon inspection, the two day old replacement seals have a few cracks, perhaps from prying them out of their slot with the chopstick?

edit: This is a photo of the two day old seals, minus the broken one: