cannonsid

The prevous owner added a vacuum booster to the manual (single) master cylinder on my 1965 disc brake car (originally manual brakes).
I want to get rid of the power brake booster and install a Wilwood manual master cylinder.
What was the bore of the original single master cylinder?
Any recommendations for a new Wilwood manual master cylinder? 7/8", 1", 1 1/8"
Thanks

anyChevy

I'm not sure on the bore size, but I'm considering adding a booster to my 66 (same MS) did it work o.k. ?

cannonsid

Yes, the booster worked fine.
I am blinging up the engine.
The booster plus the master cylinder covered up too much of the drivers side of the engine.
So I removed both and am going to replace with a Wilwood master cylinder.
I just need to know the original stock bore diameter.

0Todd TCE

If you plan to remove the booster and go pure manual you're going to need to go smaller. You'll never generate enough pressure with a big bore and no assist. *at least that's my opinion on it. With a smaller bore you'll also lose tactical feel somewhat and have a longer softer pedal. There aren't too many 'up sides' to this plan.

65GGvert

I have an original dual master cylinder (p/b) 65 that I just rebuilt. It has a 1" bore. I don't know about the single 65 m/c. Hope that will help.

Sky65

Pretty sure the stock m/c is 7/8" for non power brakes. I have a 65 and went to a 1". Pedal is higher and harder than stock but takes noticeably more pedal pressure than stock. I used one of these. I like the look in the car.



http://www.speedwaymotors.com/Alumin...ore,50598.html

Tom

claysmoker

I just replaced a 1" bore with a 7/8" Wilwood. It has noticeably better performance.

larrywalk

I used the dual master cylinder from Speedway like Sky65. It has a 1" bore diameter which is perfect for manual brakes (power brakes use a 1 1/8" bore), plus it is aluminum and considerably lighter than the cast iron dual M/C used in '67, which I previously used on my '65.

Bear in mind that usage of a 7/8" bore M/C will reduce pedal forces by 23% compared to a 1" bore, but will require an 30% additional pedal travel to get the same braking forces.