I'm building an BBP 8-3/4" axle assembly from scratch for my '64 Valiant. I have two sizes of brake backing plates that I can use. I believe one set is for 10" X 1-3/4", and the other is for 10" X 2-1/2".

I have to buy new drums, shoes, wheel cylinders and master cylinder so I have some decisions to make.

The suspension and front discs are from a '74 A-body, as is the safety switch/distribution valve. Would the 2-1/2" brakes give me too much rear braking? Without a proportioning valve, I won't have adjustability if the big brakes cause the wheels to lock up.

What about wheel cylinders and Master cylinder with either combination?

Drum suggestions?

If you're using big bolt pattern axles or any axle with that wheel bearing to axle flange dimension you have to use the 2 1/2" wide shoes and the matching backing plates. The small bolt pattern axles don't stick the axle flange out away from the axle housing as far as big bolt pattern axles. This is why swapping an A-body 8 3/4 housing to big bolt pattern with shortened big bolt pattern axles ends up about 3/4" wider overall. If you have too much rear brake there are smaller diameter wheel cylinders from 10" brake Dakota pickups available. I'm using Dakota wheel cylinders for the 8 1/4 under my Valiant.

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Joshua

Does that also apply to Yukon axles with green bearings?

I routinely use the smaller 13/16" wheel cylinders on 10" rear brakes — they were first used in '62 on Chrysler-built cop cars to prevent rear lockup. Not sure why they reckoned it was okeh for civilian cars to lock up the rear brakes, but a lot of A-body disc brake systems have ugly premature rear lockup issues; the 13/16" wheel cylinders in the back clear it up perfectly. WC37696 Raybestos or Bendix equivalent.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Do you still need a proportioning valve with front disk applications if you use the 13/16ths cylinders out back? I'm thinking probably yes, but thought I'd ask just the same.

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.