Help! Lower Burr Carrier Bolt Removal on Rio Super Automatic (aka Mazzer Major)

#1: Post by **thom8143** » November 26th, 2021, 11:53 pm

Any tips on how to break the allen head bolt in the image below loose? It is the bolt holding the lower burr carrier in place and it has withstood my best efforts even with my impact driver.

Thought about spraying it with some sort of penetrating oil, but I am a little concerned about spraying that inside the grinder even if I am tearing it down and cleaning all the components.

#2: Post by **Marmot** » November 27th, 2021, 12:53 am

I would try heat first. Use a heatgun if you have one or else a hairdryer or even torch. The burr carrier also seems to be stuck often but there are several tips for that on the forum.

#3: Post by **Marcelnl** » November 27th, 2021, 10:42 am

if heat does not work some WD40 may just do the trick, no worry needed...you can (and probably should) clean the chamber quite well.

#4: Post by **yertchuk** » November 27th, 2021, 10:59 am

Is the bolt reverse thread by any chance?

November 27th, 2021, 3:22 pm

I entertained the same idea about it being reverse thread. Tried to loosen it in the opposite direction without any luck.

Tried heat and did not budge. Sprayed some penetrating lubricant on it and I am letting it sit.

Any chance someone has any type of service manual/info on Mazzer grinders?

#6: Post by **Marmot** » November 27th, 2021, 3:43 pm

This should be the kind of screw holding the lower burr carrier. You can imagine how much resistance that can build up when even a very short bolt can become impossible to loosen. I guess penetrating oil will help but probably not get very far. Maybe applying intense heat with a burner directly to the head of the bolt would help but you could risk damaging engine parts further down.
At least I'm pretty sure the thread is normal on this bolt according to the picture

#7: Post by **Marmot** » November 27th, 2021, 3:49 pm

I'm sorry! That seems to be the screw for doser adjustment on Mazzers with doser. Your screw should be considerably shorter.

November 27th, 2021, 4:05 pm

I'm kind of glad you are wrong

#9: Post by **Marmot** » November 27th, 2021, 4:11 pm

Burr carrier screw loosening using espresso detergent?

This is something else I have found. Maybe tabasco could help in your case as well

#10: Post by **trumz** » November 27th, 2021, 4:20 pm

Have you tried putting a metal rod (solid screw driver) in through the chute wedged under the burr carrier? This will stop the burr carrier from moving when you're unscrewing the top screw. A long allen key with an extention (small diameter pipe) should do it.
That screw and washer don't look stock. You're usualy able to get a wrench to hold onto the top of the burr carrier...