I am having problems remembering how to properly size a rear wheel cylinder for more or less lockup. The car it will be going on is a 1965 valiant 2dr with 10X2 rear drum, BUT it is not chrysler rear drums and there is a huge available list of diameters for this setup. My choices are 11/16, 3/4, 13/16, 7/8, and 15/16. If it helps the front are 10.87 disc with "pin" type mopar calipers.

The WC that are currently on the baking plates are a 7/8 but I haven't peeled the seals back to see if they can be rebuilt.

Due to stupid cost of the correct width 8.75 axles and the scarcity of BBP 8.25 I sourced a toyota truck axle. It is 55" wide at the wheel flange, comes with 10x2 drums, and a 3.91 gearset for $200.

13/16" was always my go-to for 10" rear drum cylinders. The 15/16" factory-installed ones are too damn big, and Chrysler knew it; see here. Could probably run the 7/8" (=14/16", between the other two sizes I mention here) with 10" front drums rather than discs, but I'd still prefer the 13/16" in back unless I routinely carried or hauled heavy weight…and then I'd want discs up front, so I'd be back to wanting 13/16" cylinders in back!

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

Thanks for that linked info Dan.

Greg

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http://www.youtube.com/hyperpack

Would 3/4" be ok for 10 x 2 1/2" rear drums and front disk (65 two door B-body)?

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-MattMan
LEANED & MEAN

I know that whatever they put into a 78 2 door b body from the factory with 10" brakes is awful touchy....

I'd call 3/4" (12/16") rear cylinders undersized. Remember, those cop cars that originally got the 13/16" cylinders as a fix were B-bodies. I don't mean to sound like an evangelist about it, but every time I replaced 15/16" rear cylinders with 13/16" ones, the result was really, really good.

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

Wish I had known this when I had my '78 Apsen

I chaed my tail with everything on that car rebuilt master cyl. prop valve etc etc. replaced shocks, tires, etc. Always touchy rear lockup!


If I could have spent $26 dollars on some undersized rear cylinders that would have been cool!


Now I know.

Awesome.

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http://www.youtube.com/hyperpack

Long ago, my dad could have used Dan's fix. He had an ordered 1978 Chrysler Lebaron. Same problem with easy lock up of rear drums. I guess that the Lebaron was essentially a post '67 A body.
Despite multiple dealer and other visits, it never was much improved in the 10 years that he owned it. Years later, I read of one other fix which involved fitting a Ford portioning/ metering valve without quite so much initial rear brake bias.Swapping out rear brake cylinders would be cheaper and easier.

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1982 Dodge D150 ( Ram)
225 with A833OD. 2bbl. Non power brakes

Back in the 90s mopar action covered the rear wheel cylinder sizing. I couldn't remember which sizes worked best and couldn't find any easy search results for the topic. So I started this thread knowing that someone here would know a good answer. Now when someone searches they have this resource. Thanks for the answers.

No, the '78 LeBaron was a C-body, much bigger than an A-body.

…with that publication/author's usual delicious blend of truthy-flavored nonsense, made-up wishguesses, baseless claims, and a percentage of whole-grain facts. Part of this complete breakfast; stays crispy and crunchy in milk, yum-yum!

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

Wrong again.
The 78 LeBron was actually one of the first of the M bodies

Oh! Whatchya mean 'again', what was I wrong about before in this thread? Is this like that preaching thing you were on about the other day?



Derp, right—I was thinking of the Noo Yawkuh.

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