Brembo Calipers F08 why two size bleeder screws and where to find the 4.5mm?

[giusto]

Been working on putting back my 1976 Convert on the road...has not run in over 20 years....motor is running great...I figured out why no power to the rear wheel and all is good...I am in final stages with Brakes system to rebuild. I do not understand why Brembo used two different sized bleeder screws on their calipers (F08)...6mm and something like 4.5 mm? First question is....does anyone know where I can find them? MG has only the 6mm listed
second question...there must be a reason for the different sizes...it's for bleeding....nothing to do with a running system...is there a hydraulic engineer out there that can inject reason for this goofiness.

comical and nonsensical answers are always welcome to question 2

[Antietam Classic Cycle]

Brembos used on the Convert should have 6 mm bleeder screws. I've never seen 4.5 mm bleeders - only 6 mm and 10 mm. 

[giusto]

Brembos used on the Convert should have 6 mm bleeder screws. I've never seen 4.5 mm bleeders - only 6 mm and 10 mm.

That makes sense to me...the 6mm fits fine on the inside bleeder....outside is smaller...and no trace of a hela coil
I tried to screw in a 5 mm screw...too big and a 4mm screw...too small
 

[Curtis Harper]

Harper's has all the brembo parts you'll need.

[yackee]

Probably worth it to replace all the calipers anyway, if they have the original chrome pistons they are likely rusted up.

[giusto]

Probably worth it to replace all the calipers anyway, if they have the original chrome pistons they are likely rusted up.

 The calipers are in excellent shape… I rebuilt them with new seal kits and brand-new Pistons... I'm trying to keep what was the original on the bike original and these calipers needed no replacement 

 Just intrigues me that there are two different size bleeder screws.
 I have a local friend that has a similar era El Dorado and his calipers also have two size bleed screws

[jacksonracingcomau]

That makes sense to me...the 6mm fits fine on the inside bleeder....outside is smaller...and no trace of a hela coil
I tried to screw in a 5 mm screw...too big and a 4mm screw...too small

Try 3/16", this has been done in Amurka, well if it's invisible, but it has been done

[twhitaker]

3/16 is close to a number 10 screw. They are available 10-24 and 10-32. FWIW a 10-32 will screw several threads into a M5 hole but not visa versa. Wouldn't think Itly would use SAE threads but worth a try.

[rodekyll]

Bleeders are shaped 'special' for their job.  Without the right diameter, length, and angle to the bottom they won't seal.  If yours was sealing it is not a random screw.  It was a proper bleeder.

The only difference I am aware of with F08's is what Charlie said.  There is a small hole and a large hole version as well as single and double bleeder versions.  I get the larger with two bleeders when I need one on account of they're more forgiving of rust and corrosion, and even if you do twist off a bleeder you still have another one.

[Perazzimx14]

Mash the link:  http://www.mgcycle.com/index.php?main_page=product_info&cPath=110_115&products_id=593

[giusto]

I have the 6 mm bleeders as shown
  The calipers on my convert and the calipers on my buddies bike are exactly the same...one 6mm hole and one smaller hole... The smaller hole is something between four and 5 mm.
 Just as roadkiyllmentioned I don't want to tap out a new 6 mm hole as it would be nearly impossible to get the right angle and seat a 6 mm bleeder.