Rear brake size?

[72cudamaan]

So I decided to put disc brakes on the front of the car. Now I need
to decide on 10" or 11" rear drum brakes. I need opinions and reasons please.

  By the way, I don't have backing plates or any hardware, so that isn't an issue
for size.                                                              Thanks

[TreeFrog]

I would vote 11"

[dodj]

Personally I would think the smaller brakes would be more than enough. The problem as I see it with the e-body brakes is too much bias to the rear. Before I put a wilwood valve in my rear brake line to choke it off, my rears would always lock up first - I have the smaller brakes . Some people have used different wheel cylinders to reduce rear brake force.  My 

[brads70]

I have the 10" drums on the rear now as that's what came on mine ( /6 car) It now has Viper calipers/C-Body rotors on the front, and the truck rear wheel cylinders. I plumbed in the wilwood adjustable P-Valve but never had to use it, it's always been wide open.
Hope that helps?

[dutch]

Mine has factory discs and 11"in the rear.  The rear brakes were waaaay too happy... I am going with the willwood adjustable prop valve to compensate that.  No experience with 10", but I`d say they will do just fine.

[MEK-Dangerfield]

I got the stock 10" drums here.

[72bluNblu]

The factory bias tends to be toward the rear. If you're running going to be running stock 10.8" disks in the front, you may want to stick with 10" drums in the back.

Another solution would be to run bigger brakes in the front too though. I run the later 11 3/4" front disks that came on the '76-'81 cars with 11" drums in the back and the stock proportioning valve with no issues. I forget which size wheel cylinders I have back there though, there are two sizes, and it does make a difference with the front/rear bias.

Also, if you need a set of the 10" rear drum brakes, let me know. I've got a couple of complete sets I could part with.

[4 speed fish]

I think cars with power front disc brakes came with 10'' rear brakes, when I built my car I put 11 '' front power disc and 11'' drums in the rear.The car stopped good.The 10'' rears are not as hard to find compared the the 11.If you are going manual disc front I would go with  11 on the rear.

[72bluNblu]

I think cars with power front disc brakes came with 10'' rear brakes, when I built my car I put 11 '' front power disc and 11'' drums in the rear.The car stopped good.The 10'' rears are not as hard to find compared the the 11.If you are going manual disc front I would go with  11 on the rear.

Pretty much all of the e-bodies came with 10" rear drums, it wasn't a power vs. manual brakes thing (my '72 was a power disk, 10" drum car). The 11" rear drums were more common on the earlier B and C bodies, as well as the later B and F/J/M bodies. The 11" drums also come in 3 different sizes, 11x2 (earlier), as well as 11x2.5 and 11x3". All bolt right up as long as you match the whole set up (ie, you can't run 3" shoes and drums on a 11x2.5" backing plate as the offset is different)

[Katfish]

For looks alone I would go with the bigger finned 11" rear drums.

I have the 11.75 up front with 11" drums and the smaller 7/8" wheel cylinders.
The car will still lock up the rears slightly before the fronts with the stock proportioning valve.

I don't want to add an adjustable valve, so next time I change the rear pads I'll put on 2" instead of the 2.5" pads.

[72cudamaan]

Sounds like the 10" version is what I need to look for.

Also, if you need a set of the 10" rear drum brakes, let me know. I've got a couple of complete sets I could part with.

Thanks for the offer,but I think any savings would be killed by shipping. I'm in Michigan. Anyone else closer maybe? 

[72bluNblu]

For looks alone I would go with the bigger finned 11" rear drums.

I have the 11.75 up front with 11" drums and the smaller 7/8" wheel cylinders.
The car will still lock up the rears slightly before the fronts with the stock proportioning valve.

I don't want to add an adjustable valve, so next time I change the rear pads I'll put on 2" instead of the 2.5" pads.

2" wide pads won't work on a 2.5" brake set up, the offset on the backing plates is different. If you switch to the larger 15/16" wheel cylinders your brake feel would improve, it takes longer to move the larger amount of fluid. I checked and I'm running the 15/16" wheel cylinders.

Sounds like the 10" version is what I need to look for.Thanks for the offer,but I think any savings would be killed by shipping. I'm in Michigan. Anyone else closer maybe? 

I'm pretty sure I can disassemble the backing plates and fit the plates and hardware in a flat rate USPS box. You'd probably want new shoes and drums anyway. You can get finned drums for the 10" brakes. Won't look as good as 11's if you're going with larger rims, but they look better than the stockers.