Educate me about master cylinder bore size

DWDarkWheels Posted a lot Posts: 1,807	Educate me about master cylinder bore size DWDarkWheels @darrylwebb
	Aug 17, 2012 19:42:48 GMT Select Post Deselect Post Link to Post Back to Top
	This is a call to those who understand brake engineering. I'm looking for a 'Dummies guide'. I understand how a master cylinder works, and how a servo assists, but what decides the bore of the master cylinder? A Scimitar runs a .875" bore (or 22mm). Why is it a bad idea to build my Scimitar with a 1" bore m/c ? Why is it a bad idea to build my Scimitar with a .75" bore m/c? Why is it a bad idea to run any of those master cylinders without a servo, when a Westfield stops sharply without a servo? What determines why one servo is more powerful than another servo ?
	Last Edit: Aug 17, 2012 19:50:59 GMT by DWDarkWheels 'Scimega' Scimitar X30XE build : retrorides.proboards.com/index.cgi?board=readersrides&action=display&thread=109014&page=1 Renault Master Motorhome (modern) : retrorides.proboards.com/thread/168690/renault-master-campervan-modern Cheap Cougar comeback :forum.retro-rides.org/thread/217123/2000-v6-ford-cougar-comeback Still playing with cars, but 1:1 scale now.

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davemnw Part of things Posts: 22	Educate me about master cylinder bore size davemnw @davemnw
	Aug 17, 2012 20:33:39 GMT Select Post Deselect Post Link to Post Back to Top
	The master cylinder size is determined by the volume of fluid that needs to be moved into the brake calipers/cylinders for a given pedal travel. A larger cylinder will need less pedal movement than a small one, but will need more force on the pedal. So... If you fit the 1" cyclinder you'll have less travel on the brake pedal but it will be harder to push down. If you fit the 0.75" cylinder the pedal will be lighter, but it may end up hitting the floor before the brakes work. The westfield copes without the servo because it's much lighter than the Scimitar, so doesn't need as much braking force to stop it. Hope that helps!


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DWDarkWheels Posted a lot Posts: 1,807	Educate me about master cylinder bore size DWDarkWheels @darrylwebb
	Aug 18, 2012 8:02:09 GMT Select Post Deselect Post Link to Post Back to Top
	Thanks Dave, good explanation. I'm planning to change the single-circuit remote-servo arrangement on the Scimitar, so wanted to understand what I should or shouldn't replace it with :-) Cheers.
	'Scimega' Scimitar X30XE build : retrorides.proboards.com/index.cgi?board=readersrides&action=display&thread=109014&page=1 Renault Master Motorhome (modern) : retrorides.proboards.com/thread/168690/renault-master-campervan-modern Cheap Cougar comeback :forum.retro-rides.org/thread/217123/2000-v6-ford-cougar-comeback Still playing with cars, but 1:1 scale now.

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sparkyt Posted a lot selling stuff Posts: 1,767	Educate me about master cylinder bore size sparkyt @trevorhutchins
	Aug 18, 2012 8:17:59 GMT Select Post Deselect Post Link to Post Back to Top
	If you go to bigger brakes like the 4 pots or large 2 pot you may need to move a little more fluid to get them to work do going up a size may help you .. when I took the brakes of the Megan turbo ( big brembo 4 pots ) for the corrado I took the cylinder from a bigger heavyer car in the same range (none abs car ) to help it stop .


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