Drum vs Disc, Power vs non Power

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Papaduster

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I keep reading everyones opinion on SBP brakes or LBP brakes. Or even if an A Body car needs a power brake set up. On one thread one guy wanted to do power drums, He got a reply as its not needed due to the A Body cars weight. If thats so then Disc brakes arn't needed either. As a good 4 wheel drum manual brake set up and new formula brake shoes are just fine, So why go to the added expense of swapping from SBP drums to LBP disc then and the added expense of new wheels if you already own SBP Rallys? Oh I know some are saying cause you get a better look and better wheels in 15''-17'' rims. And I think some just like the way Disc brakes really look and so do I. Back in 1972 I went to a junk yard and got a set of SBP disc brakes, then while I was in Holland a guy gave me a set of SBP Rallys off his Duster , later I nstalled a power booster and what a diffrence it made in stopping and comfort feel of the brakes. Now I still own my orginal Duster and since have aquired another Duster. so as not to waste or try and sell my extra parts Im using them on the second Duster and yes It'll have a 4 wheel drum brake set up with a power booster. I'll save money rebuliding the drums as most SBP disc or LBP disc will cost me an extra $275-300 which is what I'll be spending to rebuild the drums, And I wont need new wheels as my Rallys will go on the seconed Duster, I'll post my results as I think it'll be a good project to see how it stops and feels
 
Do you understand the differences in performance between drum and disc brakes?
 
I'll throw in my $0.02.

My Duster came with 4 wheel, non-power drums in the 10" variety from the factory. They actually worked excellent when they were on the car for what they were. The first stop or two were fine as they had no trouble overpowering the 195-70R14 tires that were on the car.

In 2002, I swapped the rear axle to an 8.25 with 10x2.5 LBP drums in the rear and promptly added the standard 73-76 LBP disk setup with slider calipers (they are the larger 2.75" pistons) and 10.87" rotors. I put the manual MC on for this with the stock 1 1/32 iron MC and added an adjustable proportioning valve. I was immediately able to test this and missed a deer by probably 3 feet. The car did stop better, however, for that single stop, I think it was improved mostly by the much larger 225-60R15 tires I was able to run all the way around...they are much harder to lock up. The disks had some influence for sure though.

Just this past weekend, I changed the front brakes to the 11.75" setup and some braided stainless brake hoses. This braking system is absolutely fantastic. Nice modulation and very strong, repeatable braking performance. Its about as good as my new car. I still run the same size tires, but I have some grippier BFG G-force Sports now.

I feel that there is not any need for power brakes unless that is your preference. If you think the pedal is too stiff, run the smaller MC (15/16" IIRC).

The most important thing for braking performance overall is tires. Disk brakes are far more repeatable and do not fade.

I would not own the car without the wider tires and the BBP brakes at this point anymore. Too many idiots on the road. Even if you don't want to go to that level, make sure you install an adjustable proportioning valve so the rears don't lock up first. These cars seem to have a tenancy to do that even when stock.

I'd leave the 4 wheel drums to the stock resto crowd if it was me.
 
Yup I understand Disc and big bore calipers, What Im talking about is using up the parts I have, Rebuilding whats already on the car and save some Bucks$$ And since my Duster isn't a road ralley car or diven in the steep hills or raced then my 4 wheel drums should be fine and now since the manufactures are making better brake shoe linings it'll be just fine. Ill get down the road look good and make it to the Drive In Dinners and car show all without going over budget. So what Im saying is if its a light weight A body why not do drums
 
My opinion:
The higher the speed and longer duration braking demands better design and quality of parts.
The drum design is flawed because it pushes outward on a thin cast iron sleeve - combined with high heat causes problems when put in severe conditions. Add splashing water on there while they are glowing and the drum is bound to warp or maybe explode. Have you ever been going 150 down a 1 mile hill in a 3200 pound car and tried to stop on a dime? I have had many factory brake systems fade to the floor many times and go back to quasi normal 30 seconds later. Most the time they can handle this treatment only about 5 consecutive times before wheel bearing grease is cooked, drums and discs are warped. I have had drum brakes temporarily fail many times after driving thru a low water bridge or really soaked part of the road.
Road racing or spirited touring type driving will demand continual severe braking cycles. Larger tires, larger wheels both also place added demand on brakes, both in leverage and traction.

Its all about what you do with the car. If you plan to drive moderately, drums must be fine as people have been running them for years. I had a 69 coronet big block with large 4 wheel manual drums and it worked great with autozone pads. But I did not push the limits of the braking system much at all as I knew it could get me in trouble.
 
Well, it might be ok if you live out in the sticks. You wouldn't want to live where I do and drive on the main roads with 4 wheel drums, it would be pretty risky.

I daily drive a 2012 Chevrolet Cruze 2LT, has 4 wheel disk brakes with rotors that will clear 15" wheels that are roughly the same size as what I installed on the front of the Duster. They are single piston, ABS with electronic brakeforce distribution. Stops from 60-0 in 122 feet and can do it repeatedly. I am very confident driving this car.

Now, the Duster with the upgraded brakes feels pretty strong and I'm confident it could stop in the 130-140 ft range from 60 with the right modulation and be repeatable. When it had drums, it might be able to do 180-185 feet on the first stop with it getting worse on every stop. 40 feet is like plowing through two cars.

The reason for better brakes is to avoid what you don't expect out there. Stay safe.
 
I'm putting on front discs because I remember losing my brakes every time I went through a deep puddle back when these cars weren't all that old and I had one for my daily driver. You'd spend the block or two after driving through the puddle 'drying out the brakes' by riding them. (Not a lot of storm drains out in the southwest, since it doesn't rain all that often.)
 
Actually, come to think of it, you could probably do the SBP Scarebird disk conversion for just a bit more than it would cost to rebuild the drums. I have a friend who has those and its sure better than it was originally with the drums.
 
Thanks for all the tech info, I know and understand the diffrences between drums and disc Im just saying for $230 to rebuld all 4 drums and get the car on the road so I can go to car shows and have fun is what Im looking to do right now Thats not saying in the future I wont upgrade to SBP disc Yea I know Scarebird sells the disc conversion brackets but then all the other conponets arn't mopar brakes anymore so Id rather have drum brakes now and dive my car withoiut all the extra added expense
 
Drums would be WAY more efficient than discs were it not for one thing. They cannot dissipate heat like discs. If they could and not fade, drums would be on everything made still today. Unfortunately, that's not the case. After three or four hard stops, drums heat up and fade.

All that said, I am a BIG proponent of drum brakes on a street car. Even a race car down as fast as high 10s. Drums are better than discs.....until they begin to fade. Look at the difference in the surface area of a drum brake shoe VS a disc brake pad.

Drums are also much lighter than their disc counterpart. Drum brakes can stop unbelievably quick as long as they are in good working order and have not been neglected. I plan on keeping the drum brakes on my 65 Coronet and it's not gonna be slow with a big block and 4.56 gears.

Road racing? Drums probably not a good idea. I would run them on a drag car real fast. Since they don't have to repeatedly stop and they are light, they are an excellent choice down to a certain ET. JMO.
 
I have a 71 Duster, After I broke the upper Ball joint on the passenger side I took the plunge and did tubular upper control arms willwood 12.19 inch drilled and slotted discs with 4 piston calipers and steel braided lines from magnum force racing. It was the best decision I ever made. stops amazing looks badass I will never suffer under drum brakes again. I cant wait to get a Dana 60 in the rear with discs.
 
Yes there are stopping advantages changing from drums to disc, but if your car is sitting due to needing a lot of major rebuilds like paint, interior , engine rework, tires and brakes we somtimes get caught up in all the cool tech stuff and overthink what really needs to be repaired, fixed and upgraded and it then becomes a lot of cash out flow and thus our beloved car sits not being driven Id rather just fix for now what Mother Mopar put on my Duster and have fun driving my car. I'll spend less money and be HAPPY
 
Oh, I totally think if you can get on the road by freshening up the drum system rather than spending money and time that is needed elsewhere then let er roll.
 
RustyRatRod said:
Drums would be WAY more.
Click to expand...

I can't agree especially in "today's world."

"How well" drum systems work depends entirely on the quality AND FIT of the shoes to the drums. The fact is that today, you can no longer buy proper drums for some of these old cars, in some cases you don't have much choice on performance lining, and most of "us" no longer have arcing machines, etc (thank Gawd, the dirty filthy things) -- to fit shoes to drums.

Last, disc technology, improved -- pad lining has moved forward where drum technology has not only stagnated but in some cases become unavailable.
 
You'd be better off putting your $230 into a Scarebird conversion than spending it on drums and then spending it again when you upgrade later.

As far as "Mopar" parts, pretty much all the rotors and brake parts are made in China anyway, so does it really matter if they're for a Mopar or a Toyota?

Drums, if they're perfectly adjusted, dry, and cold can provide as much or more braking power than disks. Problem is, they're almost never adjusted perfectly, on a daily they get wet, and after a few applications they're not cold anymore. And as '67 Dart pointed out, any drums you can get now are made overseas, and the selection is dropping rapidly. It's already not easy to find some of the variations of the drums that came on these cars.

I've converted all of my cars to the 11.75" Mopar disks. They work great, even with the 275/40/17's I run on my Challenger. That thing will stop in a hurry, it plants the nose despite the 1.12" torsion bars and Hotchkiss UCA's I have with the anti-dive taken out. I wouldn't drive anything on even a semi-regular basis with 4 wheel drums, too many idiots out there.

Power brakes aren't necessary, especially for the lighter A-bodies. I have them on my Challenger, but have manual on everything else and I actually prefer the manuals. Much better feel. Takes more leg, but I think it gives better precision.
 
RustyRatRod said:
Drums would be WAY more efficient than discs were it not for one thing. They cannot dissipate heat like discs. If they could and not fade, drums would be on everything made still today. Unfortunately, that's not the case. After three or four hard stops, drums heat up and fade.

All that said, I am a BIG proponent of drum brakes on a street car. Even a race car down as fast as high 10s. Drums are better than discs.....until they begin to fade. Look at the difference in the surface area of a drum brake shoe VS a disc brake pad.

Drums are also much lighter than their disc counterpart. Drum brakes can stop unbelievably quick as long as they are in good working order and have not been neglected. I plan on keeping the drum brakes on my 65 Coronet and it's not gonna be slow with a big block and 4.56 gears.

Road racing? Drums probably not a good idea. I would run them on a drag car real fast. Since they don't have to repeatedly stop and they are light, they are an excellent choice down to a certain ET. JMO.
Click to expand...

Drums better than disks? There really isn't anything that supports that.
http://www.popularhotrodding.com/tech/0709phr_wilwoods_disc_brake_swap/

Not only that, even the big rigs which can get away with drum's propensity to lock much easier than a car (heavier weight) are going to air disk brakes for shorter stopping distances (this is/is going to be an FMVSS requirement).

They even sell the Cruzes like mine with rear drums...my rear disk car stops 10' shorter...and the front brakes are the same...and that's with electronic brake force distribution AND ABS.

I won't push anyone to install rear disk brakes on their car, however, I think its pretty short-sighted to not install front disk brakes. Your cheapness may destroy the car, hurt you, or hurt someone else since you may be unable to stop in time to miss an object that you would otherwise be able to avoid. Its the same reason why I also want everyone to have front anti sway bars and at least 205 tires on the front axle.

On a drag car, do what you want. On the street however, think about the unpredictability.
 
72bluNblu said:
I've converted all of my cars to the 11.75" Mopar disks. They work great, even with the 275/40/17's I run on my Challenger. That thing will stop in a hurry, it plants the nose despite the 1.12" torsion bars and Hotchkiss UCA's I have with the anti-dive taken out. I wouldn't drive anything on even a semi-regular basis with 4 wheel drums, too many idiots out there.
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I agree. The 11.75" brakes with the 2.75" bore calipers work totally fantastic. Its borderline shocking how good they are. After fading my rear drums during my brake bedding process for the front pads and the fronts loosing nothing, it might be time for rear disks down the road.
 
Read the WHOLE thing. Drums WOULD BE is what I said. WOULD BE. IF they could dissipate heat. They cannot so they are not.
 
Another thing to take into account, I'm having trouble locating 10" for my 69 Cuda. The better brands have dropped them (one bloke quoted $400 for each drum-Bendix). I can get 'no name' ones over here for about $280 a pair, which would be about the same cost as to get them from the states to here, but how good is the quality? disc might be the best in the long run.
Cheers,
Monaro.
 
Looks like most guys are in favor of converting to Disc front brakes and so am I, its just Im on the tightest of tight budgets of all, so to get my Duster drivable and on the road I'll opt out for a $230 plus drum to drum brake rebuild, I'll keep my SBP Rallys and use BFG 215/70/14 front and 225/70/14 rear With the brake rebuild and tires plus a few cans of rattle can paint I'll hvave a decent looking daily drivable Duster and all for $800 plus Which is a lot less expensive than converting to Disc minus tires at over $1,500 plus. My main point is build what you have get your car on the road and save some money, not everything has to be high tech to drive Some things are just Old School and thats OK
 
Papaduster said:
Looks like most guys are in favor of converting to Disc front brakes and so am I, its just Im on the tightest of tight budgets of all, so to get my Duster drivable and on the road I'll opt out for a $230 plus drum to drum brake rebuild, I'll keep my SBP Rallys and use BFG 215/70/14 front and 225/70/14 rear With the brake rebuild and tires plus a few cans of rattle can paint I'll hvave a decent looking daily drivable Duster and all for $800 plus Which is a lot less expensive than converting to Disc minus tires at over $1,500 plus. My main point is build what you have get your car on the road and save some money, not everything has to be high tech to drive Some things are just Old School and thats OK
Click to expand...

Rebuilding the 10" drums won't be that cheap though if you start needing to replace too many things with new parts. If you need new drums, forget about it.

Honestly, get a Scarebird kit and source your parts from the local wrecking yard. $105 bucks for the kit, $135 for new rotors already drilled for 5x4" from Scarebird. I bet you can get the rest of what you need for $100 at the local yard. Heck, if you can drill a set of Toyota rotors for 5x4" you can save a ton right there.

Not to be a doomsday-er, but daily driving a Duster with the cheapest drum brake parts you can find may end up costing you a lot more than a few hundred bucks.

It's your car, so do what you like. My old man had a saying for this though. If you can't afford to do it right the first time, you sure as heck can't afford to do it twice either.
 
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