rear disc brakes vs rear drums

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moparmat2000

moparmat2000

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Hi everybody
I'm at a crossroad on my project. I like the look of 4 wheel discs, but dont like the way i have to put them on the axle for my project car. Would prefer to keep it all mopar and bolt on.

I have used a set of 79 cordoba big brakes on 74 dart spindles on the front. I am thinking of grabbing the 11" x 3" finned drums off the rear of this car. This would end up being a true bolt on to an 8.75 rear including parking brake. All mopar with severe duty drums. Hopefully if i go the drums direction my wrecking yard still has this car so i can get these parts.

Bottom line is i can go with the GM caliper/ weld on bracket setup with jeep or lincoln rotors , figure out a parking brake setup and make it work, or get the heavy duty rear drums off the same car i got the front discs from along with master cylinder and proportioning valve, and have bolt in and go goodness.

Will a well setup heavy duty disc / drum setup off an xtra large barge 79 cordoba fitted to my 67 barracuda coupe work as well as doing the cordoba discs and a custom made rear disc setup in the rear? Or is it just the wow factor of rear discs, and the severe duty drums should stop my car just as good as the rear discs will.

Matt
 
just take all the gear from an 8 1/4 rear jeep; but I wouldn't I don't like rear disc's around here because there all the time seizing up and they wear at twice the rate; but I also live in a cold province in the rust belt
 
My 2 cents is to go with the drums on the back as the bulk of the stopping is done with the fronts. The problem with rear disc on 8 3/4 is you have to go with green bearings and remove the adjuster. I know that alot of people run these without any problem but I prefer the stock set up. You could also use the 8.8 from ford explorer with disc but you lose the drop out pig for gear swaps.
 
go disk for simplicity and performance. unless you enjoy fighting drums. Dr Diff has a kit that bolts on using mustang calipers and a real parking brake unlike the ghey one used on wilwoods. i have been racing his kit for two years now and love it. oh,and with the same pads.
 
go disc on the left rear and drum on the right rear and that will be a happy medium! lol.....
 
you could make it symetrical all the way around and do disc on the right front and drum on the left front also,lol---that way you have a disc on the right front and left rear and drum on the other two criss cross wheels!! now theres a true solution. lol
 
The real question is how hard are you gonna drive the car? Unless you're pushing your car to it's limits, you won't see any real benefit from rear disc brakes. Now before you go thinking that all the manufacturers are using 4 wheel discs because they're better, understand that for the most part it's being done because of demand by a public that percieves it as being better and safer. If this is a DD or a cruiser, stick with the drums.

Unless of course you take Watkins Glen or Mulholland Drive to work everyday.....
 
Drums out back. 80% of braking is front. Ever lock up the rears before the fronts? Not cool.
 
I say go with drums on the rear with an adjustable proportioning valve. Criss cross brakes guys! That's funny as hell!!!!!!!!!!
 
I have 11 3/4 discs on the front and 11x2 1/2 drums on the back of my 67 Cuda. It's all that I need, the drums work better cold and the discs better when hot. I haven't had any problem with the drums locking up and they aren't that much of a problem to change shoes. It's all Chrysler parts!!! The way Plymouth should have built a Formula S.
 
I say drums, no drag and get better mpg, and believe it or not they rob HP.
Spine a disc brake system by hand one time..JMO :glasses7:
 
Leave the drums out back. They provide more than enough stopping power for the rear wheels, which is usually only 20-30% of the braking for the car anyway. 11x2.5" or 11x3" will be more than sufficient. I run 11x2.5" rear drums on my Challenger with 11.75" front disks, it stops pretty darn well even with the stock single piston calipers. If anything, upgrade the front calipers to Wilwood Dynalites using AR's kit for the 11.75" rotors and upgrade the stock master cylinder. Money way better spent.

Or spend a ton of money on rear disks, install inferior axle bearings, and when you're all done, install an adjustable proportioning valve to reduce the braking power of those awesome rear disks so you don't swap ends under braking. Makes sense right? :dontknow:

How the heck are drums that hard to deal with? A pair of pliers and a long flat head screw driver takes care of just about everything. I mean sure, every now and then a brake spring goes flying across the garage, but if you're ever rebuilt a caliper you know the same can be said about a stuck caliper piston.
 
72bluNblu said:
Leave the drums out back. They provide more than enough stopping power for the rear wheels, which is usually only 20-30% of the braking for the car anyway. 11x2.5" or 11x3" will be more than sufficient. I run 11x2.5" rear drums on my Challenger with 11.75" front disks, it stops pretty darn well even with the stock single piston calipers. If anything, upgrade the front calipers to Wilwood Dynalites using AR's kit for the 11.75" rotors and upgrade the stock master cylinder. Money way better spent.

Or spend a ton of money on rear disks, install inferior axle bearings, and when you're all done, install an adjustable proportioning valve to reduce the braking power of those awesome rear disks so you don't swap ends under braking. Makes sense right? :dontknow:

How the heck are drums that hard to deal with? A pair of pliers and a long flat head screw driver takes care of just about everything. I mean sure, every now and then a brake spring goes flying across the garage, but if you're ever rebuilt a caliper you know the same can be said about a stuck caliper piston.
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After talking with both Baer and Wilwood plus dr diff, a stock drum/drum prop valve can be used no problem so no need use an adjustable on at least with the 11.75F/11R
 
1970Duster said:
After talking with both Baer and Wilwood plus dr diff, a stock drum/drum prop valve can be used no problem so no need use an adjustable on at least with the 11.75F/11R
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11" rear disks?

I find it a little hard to believe that the rear calipers in those 3 kits need the same amount of fluid/pressure as a set of stock rear drums, but if they say so.

Regardless, if that is true, it means that those disks provide the same amount of stopping power as the stock drums.

Heck, I think I'd feel better about the adjustable prop valve and "dumbing down" the rear disks. At least that way you're not already maxed out on your rear stopping power if you upgrade the fronts again.
 
I have the 11.75 front/11.00 rear (Jeep disc) on my Dart with the stock prop valve and not once has the rear end locked up, even when I really need to stop. Brakes have been on close to a year now.
 
superdart said:
I have the 11.75 front/11.00 rear (Jeep disc) on my Dart with the stock prop valve and not once has the rear end locked up, even when I really need to stop. Brakes have been on close to a year now.
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Ever locked up the fronts?

You should be able to lock them up under extreme braking. Ideally of course all 4 would lock up at the same time, and only when you plant the pedal on the floor.

If you can't lock them up even under extreme braking, then you're not getting everything you should out of your brakes. If its just the rears, then your prop valve may actually be too biased toward the front. If you can't lock any of them, then you've got a system wide issue- air in the lines, contaminated brake fluid, problem with the master cylinder, etc.
 
1970Duster said:
After talking with both Baer and Wilwood plus dr diff, a stock drum/drum prop valve can be used no problem so no need use an adjustable on at least with the 11.75F/11R
Click to expand...

There is no such thing as a drum/drum proportioning valve.

On a custom disc brake install, an adjustable proportion valve is a great tool to adjust brake bias. There are more factors that come into play than just the size of your brakes. Weight bias, tire size/make/differences, driving style all are factors to consider when building and tuning your brakes. You might be able to get by without a prop valve or with one of the generic ones supplied with the mass produced kits, but if you are gonna spend the dough and or effort to upgrade, why would you not want to optimize your work?
 
Revhendo said:
There is no such thing as a drum/drum proportioning valve.

On a custom disc brake install, an adjustable proportion valve is a great tool to adjust brake bias. There are more factors that come into play than just the size of your brakes. Weight bias, tire size/make/differences, driving style all are factors to consider when building and tuning your brakes. You might be able to get by without a prop valve or with one of the generic ones supplied with the mass produced kits, but if you are gonna spend the dough and or effort to upgrade, why would you not want to optimize your work?
Click to expand...
Okay it could be a distribution block then for the drum/drum setup but it would work.
 
Revhendo said:
There is no such thing as a drum/drum proportioning valve.

On a custom disc brake install, an adjustable proportion valve is a great tool to adjust brake bias. There are more factors that come into play than just the size of your brakes. Weight bias, tire size/make/differences, driving style all are factors to consider when building and tuning your brakes. You might be able to get by without a prop valve or with one of the generic ones supplied with the mass produced kits, but if you are gonna spend the dough and or effort to upgrade, why would you not want to optimize your work?
Click to expand...

Exactly!!! :thumbup:
 
Well just my 2 cents, don't mean to step on anyone's toes.
Rear drums should work fine but....the 11" drums are HEAVY. Can't remember the exact weight so I'm not gonna quote it but I believe it's around 30 pounds each. Not only is it just the unsprung weight but everytime you accelerate or decelerate you are using energy to get those things rotating. Unless you are racing down Mt. Washington or Pikes Peak, I think it's overkill on an a-body. That's why changing over to lightweight frontrunner tires/wheels on a drag car reduces the ET. I remember High Performance Mopar magazine did a simple A-B test and they were good for .15 seconds(?)

Personally I went with manual 73-76 discs on the front and BBP 10 x 2-1/2" drums on the back on my 68 cuda. Standard 10 drums on a 67-69 were 1-3/4" wide so I only added slightly more weight. Also changed to a newer 1-1/32" dia aluminum MC with an adjustable proportioning valve and eliminated the brake safety valve/tee to simplify things. KISS is good and less joints to leak or cause problems. So I tell people I pretty much have B-body brakes on an A-body and they work well for me. Not only are the brakes bigger but I'm hauling 400-500 lbs less weight too.
 
Another thing to think about, brake pads material. Disc brake pads have a far great selection then drum brakes.
 
1970Duster said:
Another thing to think about, brake pads material. Disc brake pads have a far great selection then drum brakes.
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+1 - I have ceramic pads on my car.

blu - I can lock up the fronts. I meant to imply I have not had the rears inadvertently lock up on me during hard braking.
 
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