New victim for measuring piston pressure: the BOSCO group - Page 7

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Seels
Posts: 3
Joined: Sep 16, 2017, 11:13 am

Postby Seels » Sep 16, 2017, 11:17 am

How did you get the "piston" loose?
I want to remove the inner spring of my pro 800 but cant get the piston loose. Also do you need to compress the springs in some way?
Thanks

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Homo Barista
Posts: 416
Joined: Mar 19, 2014, 1:27 pm

Postby Homo Barista » Sep 16, 2017, 3:29 pm

Seels wrote:How did you get the "piston" loose?


See picture here:
New victim for measuring piston pressure: the BOSCO group

Turn the piston counter clockwise.

Seels wrote: do you need to compress the springs in some way?
Thanks

No need to compress the spring. The threading on the shaft is long enough.

chappcc
Posts: 118
Joined: Dec 08, 2014, 9:56 pm

Postby chappcc » Sep 16, 2017, 10:53 pm

Homo Barista wrote:See picture here:
No need to compress the spring. The threading on the shaft is long enough.


This is contrary to my experience with the Bosco group on a Salvatore Compact Lever machine. I used metal cable ties https://www.amazon.com/14-Stainless-Steel-Cable-Ties/dp/B006676E38 to hold the outer spring under compression. I built a special jig to hold the group to allow me to use the lever to compress the springs. I first guided the cable ties between the inner and outer spring, so that 4-5 coils of the outer spring would be held compressed with the metal cable ties. I used four cable ties evenly spaced around the circumference of the outer spring. With the outer spring compressed, and the cable ties pulled tight, I released the lever to allow the group piston to be unscrewed to allow the inner spring to be removed. I used this tool to turn the piston: The new lever group thoughts When the shaft was fully unscrewed, the inner spring was still compressed. Re-assembly was very easy with the outer spring compressed. Just cut the cable ties when the piston is fully attached and torqued in place.

Seels
Posts: 3
Joined: Sep 16, 2017, 11:13 am

Postby Seels » Sep 16, 2017, 11:31 pm

is it a kind of grinder wrench you are using? i made something that looks like a grinder wrench and fits into the two holes on the bottom.

Do you need alot of force to assemble it again?

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Homo Barista
Posts: 416
Joined: Mar 19, 2014, 1:27 pm

Postby Homo Barista » Sep 17, 2017, 12:06 am

chappcc wrote:This is contrary to my experience with the Bosco group on a Salvatore Compact Lever machine. ....When the shaft was fully unscrewed, the inner spring was still compressed.


Great info. Thanks for sharing. They use seemingly different springs. It could be a painful experience if a spring is still compressed when the piston gets fully unscrewed. But it is definitely not the case at the Pro800.

@Seels: I use an adjustable pin wrench. And it is easy to reassemble.

Seels
Posts: 3
Joined: Sep 16, 2017, 11:13 am

Postby Seels » Sep 17, 2017, 10:51 am

Tried it, cant get the piston to move, even when i extend my wrench for more force. can i damage the rod? another option is take it to my grandfather who has more tools to do this.

OR should i take it to a pro who has experience whit this. it will cost me 95 euro (almost the same as dollar)

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Homo Barista
Posts: 416
Joined: Mar 19, 2014, 1:27 pm

Postby Homo Barista » Sep 17, 2017, 1:58 pm

Seels wrote:Tried it, cant get the piston to move, even when i extend my wrench for more force. can i damage the rod? another option is take it to my grandfather who has more tools to do this.

OR should i take it to a pro who has experience whit this. it will cost me 95 euro (almost the same as dollar)


I think it's better to get help. Without proper tools you can do some damage also.

chappcc
Posts: 118
Joined: Dec 08, 2014, 9:56 pm

Postby chappcc » Sep 17, 2017, 6:06 pm

Seels wrote:is it a kind of grinder wrench you are using? i made something that looks like a grinder wrench and fits into the two holes on the bottom.

Do you need alot of force to assemble it again?


The tool came from this set of tools designed for brake caliper work:
Image
One of the disks had the proper spacing for the bottom of the group piston. The studs are a little too small, so I knocked them out, redialed the holes for 6mm (I think - you should measure the hole diameter in the piston) and pressed in a couple of cutoff 6mm bolts.

No force is needed to reassemble as long as you keep the outer spring compressed. Cut the cable ties after the piston is reassembled and torqued tight.

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Homo Barista
Posts: 416
Joined: Mar 19, 2014, 1:27 pm

Postby Homo Barista » Sep 24, 2017, 2:23 pm

Finally some progress:

water jet cutting:



Image

Still lot to do. To the international coffee day (I should serve coffee on an event with the Pro800) we should present the dual gauge piston pressure kit.

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Homo Barista
Posts: 416
Joined: Mar 19, 2014, 1:27 pm

Postby Homo Barista » Sep 25, 2017, 5:00 am

edited

 
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