The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 47-59 What master cylinder and proportioning valve for disc/disc

nikwho · 05-15-2020, 02:24 PM

Absolutely. Under heavy braking, the rear of the truck is unloaded to varying degrees (depending on many factors) and the front is loaded. So, equal braking force between them would cause the rear to lock prior to the front. My understanding is that with the adjustable Wilwood valve that I have, I will be able to adjust that bias into my brake system by slowly decreasing the pressure to the rear brakes until the front and rear brakes are locking at essentially the same time.

So, seems as though that is mostly worked out. Are there any brake guru's out there that can help me pick my master cylinder bore diameter? Am I correct in my assertion that smaller bores give more pressure to the brakes, while larger bore diameters would give more feel? I was tentatively planning on a 1" MC bore, but have seen 7/8", 15/16", 1", 1 1/16" and 11/8", I think. I figured that I should be in the 15/16" or 1" range, but only because those are quite common, not because of any data or actual information! LOL.

Thanks much!
Nik

05-15-2020, 02:24 PM	#8
nikwho Registered User Join Date: Apr 2010 Location: Flagstaff, AZ Posts: 974	Re: What master cylinder and proportioning valve for disc/disc Absolutely. Under heavy braking, the rear of the truck is unloaded to varying degrees (depending on many factors) and the front is loaded. So, equal braking force between them would cause the rear to lock prior to the front. My understanding is that with the adjustable Wilwood valve that I have, I will be able to adjust that bias into my brake system by slowly decreasing the pressure to the rear brakes until the front and rear brakes are locking at essentially the same time. So, seems as though that is mostly worked out. Are there any brake guru's out there that can help me pick my master cylinder bore diameter? Am I correct in my assertion that smaller bores give more pressure to the brakes, while larger bore diameters would give more feel? I was tentatively planning on a 1" MC bore, but have seen 7/8", 15/16", 1", 1 1/16" and 11/8", I think. I figured that I should be in the 15/16" or 1" range, but only because those are quite common, not because of any data or actual information! LOL. Thanks much! Nik __________________ '59 Apache - 383" SBC/TH-350 '68 GMC - BBC/TH400 Last edited by nikwho; 05-15-2020 at 02:37 PM.