upgrade to bigger rear brake drums

[scarborough]

is it possible to upgrade my rear brake set up by using a bigger set drum on a 87 olds . if so does anyone have any advice or know of a site with this upgrade it would be appreciated. hoping i can find these part at local yard. i know a lot of guys are going with disc brake upgrade, but this is a budget build for me. i'm sure this will help some other budget minded builder to get them by until they can go with a better set up.

thanks
apprentice

 

[TURNA]

GM pretty much used the same size rear drum brake on all their cars.

9" x 2 1/2"

 

[fleming442]

The most cost effective rear upgrade is the 82-93 S-10 7/8" wheel cylinders and braces. It's a tight spot to drill in for the brace bolts, so take your time and get it right.

1993 CHEVROLET S10 BLAZER 4.3L V6 Wheel Cylinder | RockAuto

RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. Easy to use parts catalog.

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RAYBESTOS GMB25851 Wheel Cylinder Bracket | RockAuto

RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. Easy to use parts catalog.

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S-10 7/8" wheel cylinder swap

Since I have my rear end dismantled I thought about stepping up the brakes too. After a little digging I'm finding people claim that they've experienced rear-wheel lockup with the bigger cylinders installed. Anyone care to chime in on that? Even with an adjustable prop valve would it be...

gbodyforum.com

 

[pontiacgp]

I have seen some people use 2 primary shoes on each side. I found a big improvement with my rear brakes when I went to an 8.2 rear, the brakes were basically the same except it has a bolt in wheel cilinder so I would suggest to get the cylinder bracket that fleming442 posted a link to it

 

[spidereyes455]

If I'm not mistaken I think some 73-77 A bodys used 11 inch drums it may be possible to modify the axle housing flange in the same way you would for rear disc brakes. Though it may be more cost effective to use rear discs by the time you buy all the parts. Not to mention all it may do is lock the rear wheels up prematurely. But it is an interesting theory nonetheless.

 

[REGAL8r]

Ls1 or zq8 rear disc with c5/6 upgrade-DONE.

 

[GuysMonteSS]

While I cant answer your question,I can tell you that the Ford 9 inch under my Monte came with considerably bigger drum brakes than the 7.5 had.
Just this alone made a huge difference in the stopping power.
Guy

 

[bracketchev1221]

The 73-77 is what I was thinking as well, they had larger brakes, but the backing plate is different. the 73-77 used a bolt on plate where 78 and up used the funky clip in wheel cylinder and anchor pin to retain the backing plate. If you really want to upgrade the brakes for safety, you can replace the wheel cylinder and backing plate. The new stuff uses a keyhole backing plate to keep the wheel cylinder from rotating, and the wheel cylinder has wings on it that straddle the anchor pin so it cant rotate.

 

[pontiacgp]

I would not want to upset the balance of the stock proportional valve which manages the front to back brake bias. If the back brakes work too well braking in a straight line won't be an issue but if turning even slightly the back end will lock up and come around.

 

[malibudave]

Is this a daily? If so, I would NOT upsize the wheel cylinder. The rear brakes already are easy to lock up with the 3/4" bore wheel cylinder and a 7/8" bore wheel cylinder will make is more sensitive to premature lockup.

If this is a drag car, then MAYBE upsize the wheel cylinder, but only if you are having trouble foot braking at the starting line.

I would install the wheel cylinders brackets as the wheel cylinder do move when the brakes are applied. The wheel cylinder is supported by ONE bolt and it likes to pivot because there different amounts of pressure being applied to each side of the wheel cylinder. The brackets will also make the rear brakes more predictable because one side of the drum brakes lock up before the other because one of the wheel cylinders on one side pivot more than the other size. If you have someone apply the brakes, you can see the wheel cylinders move and each one will move a different amount. NOTE: Don't get run over while looking at the wheel cylinders move. This is most likely the most effective mod to do to your rear drum brakes to make them more predictable.

For drag racing, two long pads per side may help a little. I would only do this if you cant hold the car while foot braking at the line. Choose the brake shoe compound to fine tune your rear brakes. If you need more initial bite, then a organic compound would most likely be best, Semi Metallics usually have less bite and ceramics have the least amount of initial bite. Organics do better when cold and cannot handle sustained high temperatures, but for most cars, this isn't an issue. Semi Metallics handle the heat better than Organics and Ceramics handle heat the best. If you get to much premature lockup with organics, step up to a Semi Metallic, To much premature lockup with Semi Metallics, step up to a ceramic. This has been simplified, because all pads compounds are formulated differently between brands.

Also, there is the aluminum replacement drum. Cardone Part number 2c18000. I don't know if you can purchase these any longer. It looks as if they may be sold out.
Here are the specs.

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