Commando brake disc caliper: bleed screw thread

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pierodn

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Please,
what his the thread of the caliper bleed screw?.
I must rethread the caliper because, as usualy happens to me, the old bleed screw was broken.
Thanks.
Piero
 
They usually come in sets like the one pictured. You drill a pilot hole just smaller than the threaded area and choose the smallest or which ever so the flutes have enough engagement.
http://jaws.tips/motorbike/easyout.html
Most industrial tool and bolt place carry these. https://www.mcmaster.com/#easy-out-extractors/=1db9tpd
In the US but you could go to your Hardware stores you have in your country.
If it is stubborn, then use a little heat with a propane torch to expand the aluminum caliper around your broken nipple.

Cheers
T
 
there are many who have tried using an easyout and discovered that if you make the hole tight enough so that the easy out will screw in it is also to small and the easyout breaks off , now you are really screwed. best way is to take it to a machine shop, have them set it up so that a boring machine can drill a true hole and then all you would need to do is use a pick to remove the remainder of the thread.

the same goes for those speed bleeder screws, they will brake off, not maybe, but will
 
Hi.
Bought 1/4 x 28 tap and die.
Please, in case, what is the correct drill measure to use for?
Thanks.
Piero
 
Easy outs rarely work
I'd put a washer over the nipple and weld it ,then weld a nut to that and wind it out ,this usually works
If it doesn't work you can still drill it out
Don't forget the bottom of the bleed hole has a machined taper, don't damage it
 
baz said:
Easy outs rarely work
I'd put a washer over the nipple and weld it ,then weld a nut to that and wind it out ,this usually works
If it doesn't work you can still drill it out
Don't forget the bottom of the bleed hole has a machined taper, don't damage it
Click to expand...

Baz is right. If the bleeder broke off, that means that it is seized into the aluminum. This is a common issue with steel fasteners screwed into aluminum housings. The dissimilar metals cause galvanic corrosion. An EZ out will only break off. Then you are totally screwed, as EZ outs are harder than even a cobalt drill bit. Once you get the bleeder out, be sure to coat the threads of the new bleeder nipple with an anti seize compound, like NeverSeize.
 
I have had this happen to me, and I tried an EZ-Out extractor.
The drilling depth needed to get a grip for the extractor damaged the seat in the caliper.

I suggest heat and solvent on the caliper prior to any machining work to help loosen the corrosion.

It would be a good maintenance point to occasionally open/close the bleed nipple on our bikes.
The nipple itself can get filled with hard material to prohibits bleeding the lines.
Remove the nipple and visually check that the passage is clear.
 
Hi.
I have removed the broken bleed screw.
I have a new one and i have bought a 1/4 x28 tap.
But i will thread a new largest metric thread to fit a Brembo Ergal bleed screw.
Piero
 
Lets hope the new Brembo Ergal has exactly the same profile at the bottom, as the old bleeder screw did? If not, no sealing action...
 
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