Four Wheel Disc Brakes-Is it worth It??

I have already converted my 65 Sport Fury to front disc, is it worth the extra money/effort to go with four wheel disc brakes?

No, but then I no idea what your goals or needs are.

If you are into performance driving and make frequent hard stops, it might be worth it, but only if you've already upgraded to wider tires and wheels, do that first. For a regular driver, 4 wheel discs isn't necessary.

My Dart still has manual 4 wheel drums and it is daily driven 60 miles round trip, never had any issues getting it stopped from 70 when I needed to.

No, (and I feel that a parking brake is much more important, and many times deleted when going to rear discs) just my .02


http://stoptech.com/technical-support/te...balance-matters


jt

I added rear discs from Dr. Diff. I had one hard panic stop on a back road when a harvester suddenly appeared coming the other way taking its half out of the middle. I have no proof, but my gut feeling is that the extra braking power saved me that day. But, 99 plus percent of the time, they wouldn't be necessary. However, I feel mine paid for themselves that day.

I was on my way to a Mopar show,and a friend of mine was following me to the show in his 71 Charger R/T. Some dope pulled right out in front of me and I had to lock up my brakes. I heard my friend lock up his brakes,and looked in my side mirror hoping he wouldn't hit me. Instead of him hitting me,his car was completely sideways in the road. After that incident he installed a rear disc brake kit from SSBC,and the car stopped straight and in a lot shorter distance than it did before.

4 wheel disc brakes are unnecessary for a basic daily driver. Both of the above examples are not the normal brake stops. Decide whether or not it will ever happen to you. The second episode sounds like his buddy was following to close.

If you want to upgrade, get bigger front disc,
They do 75% or more of the braking

I'm fixin to find out. Agreed, may not be needed in most non racing apps (& maybe for most of them) but I have the stuff & want to experiment

I'm sure most of the responses here are from snail paced lounge chair car cruisers who still have 10" manual 4 wheel drum brakes, that's ok, they're fine if all you have is a leaning tower of power (/6) under the hood and only go down to the corner for a gallon of milk occasionally...

But if you have any serious power under the hood, like to street race, drive aggressively, take it to the track, then 4 wheel discs are necessary in IMHO, a well set up 4 wheel disc will pull the car down fast and straight and level, and yes you can still retain a "parking" brake

personally I prefer power assisted 4 wheel discs, decades ago I was in the same camp, "ahhh you don't need 4 wheel discs", once you start building vintage vehicles with them, you'll never want a drum brake vehicle ever again, just like an OD equipped vehicle, once you've gone this route you'll never want a 1:1 final drive ever again...but Mopar guys are always last to the school of upgrades

I have been drag racing for the last 50 years and yes front disc brakes are a great thing but unless you are running a 10 second car or are over driving your car or road tracking you don't need 4 wheel discs. Road track cars do need 4 wheel but they are a whole different critter than the average go faster.

I have a 65 300 Vert. Which kit did you use?

In a really fast car, absolutely needed. The rate of acceleration is such, you need to be able to stop as quick. Agree on the other comments. Most cars are just fine with front discs.

Yep, as long as the drums are set-up and operating properly...
No problem.

Simple test. Can you lock up the rear tires or at least make the tires squeal in good conditions in a panic stop situation? If you can, no performance advantage to rear discs for a daily driver type car IMHO.

This is assuming your disc/drum setup is properly maintained and balanced.

Kevin

Big C Body with 4 wheel drum brakes, Drove fine stopped fine

But I did upgrade to front disc, because on the highway (NJ Turnpike) bumper bumper traffic it would not stop fast enough.

But if I only stayed in CT with the car I would have never upgraded

Front disc/rear drum on a warm street driver works. I ran that for a while on my Challenger... until I burnt up the rear drums hot lapping on a road course.

Much better with discs all around now. Balanced stopping and I have not burned the brakes up.

On a mostly street driven car, the advantage of 4 wheel discs could be maintenance. Selection of lining materials for drums is getting thin. Quality of hardware is getting thin. Quality of drums themselves seems variable. Expertise is getting thin.

Rear discs based on a later model setup of some type should be a lot easier to service. The 4 wheel disc setup on my Challenger is Cobra based and serviceable with local AP store parts if needed.

I converted to 4-wheel disc last summer and I love the way the car comes to a smooth complete stop from 100 plus with very little pedal effort. I lean on my car pretty hard and it's nice to know it will stop as fast as it will go
I have 11" stock type discs on the front and Wilwood Dynalights on the rear and manual master from Strange.

Gus

It makes no sense to drive around with inferior 50 year old drum brakes,when there are affordable kits to convert these cars to four wheel discs. I have bought 4 kits so far and I plan on converting them all to 4 wheel discs.

Good to hear, I will do mine when the time comes. New territory but I will reduce the tapered bearing end play to zero & weld on some homemade brackets (8&3/4), not sure what calipers but likely 73-75 A body (2.60") in the rear and 76 (2.75) in the front (setup stock).

Good points above.
I guess I don't like change so much as I used 2, but when drum brake parts get hard to find, what else can a fella do?
Surely can't hurt.
I guess you have convinced me to "upgrade" when I get into the next brake job. Got several coming up.

I bought a set of rear discs from e-bay for my '73 Dart Sport with an 8-3/4.
I installed aftermarket axles so the inner hub of the brake hat needed to be machined a little. They have a provision to use the drum e-brake cable and overall they work excellent!

Repairing accident damage and the increased insurance costs will easily outweigh the cost of a 4 wheel brake upgrade. Don't ask me how I know!

Sorry, 4 wheel disc brakes are not going to stop you faster than disc/drums. Heck, most of the front disc kits sold for our rides these days barely stop the car at all. Too many people have problems they fail to address and blame it on "inferior 50 year old drum brakes" when the problem really is inferior knowledge, maintenance or both.

Seven miles from me is an insurance recovery lot,about 300+ cars,probably 90% are late model with 4 wheel disc brakes,not much help there.

Thanks for all the comments, I think I'll put them on the car I plan to drive a lot.

I've done three 65 Sport Fury front disc conversions. One was the scarebird kit, ok but not the greatest. Second one I found a set of spindles etc from a 73 Fury disc car, love that combo, great results. I just installed the ssbc kit for a C body but haven't driven it yet, but appears to be nice quality and set up. Easy installation.

The biggest reason late model cars have rear discs IMHO is they are cheaper in the manufacturing process than drums.

Brakes are only as good as the traction they have to work with so if the rear drums you have can overcome what the tires can supply, more brakes won't slow you down any faster.

Kevin

My 01 chevy pickup came with 4 wheel discs..

Really a no maintenance, easy to check if it needed new pads ( never did in 92K miles) and they always worked well..

Kinda disappointed the Tacoma has rear drums after the Chev..

is disk brakes worth it ,yes braking is better on everything i changed over and easier to maintain

think about this. even if you're not an aggressive driver, and maintain speed limits, when ANY other car on the road can stop much quicker, and in a shorter distance than you can....that means you'll end up in their bumper. even driving down the road at 35mph, if the car in front suddenly slams on the brakes, it's going to stop before you.
sure drums stop fine.... as long as everyone around you has them too.
what if a child, or a deer, or other animal ran in front of your car.
even at 25mph, drums vs disc could mean saving a life.

A major reason modern cars have 4 wheel discs is they are better able to handle ABS inputs. Most of the anecdotal cases mentioned so far center around emergency/panic braking, I assume most know approx 70% of your braking is on the fronts, and discs there are very useful in many situations. And the OP asked I believe mainly about rear disc addition. Furthermore, any braking force generated beyond locking up your tires, in a single panic stop, at any speed, is useless. Remember Tires stop your car. Nobody here is modulating their rear brakes close to lock in a panic stop. Normal thinking is front's should lock up before rears, and they are the ones modulated if the driver has the skills/experience. OP should spend his time/effort/money in places offering much better bang for buck.

edit: with full disclosure I'm currently adding rear discs to a street driven car , many reasons other then performance/braking issues, like rear end change (7.25 to 8.75), BP change, internal drum parking brake, tiny discs ( weight & MOI), car will see some track time, etc

Trying to convince some of the Mopar brethren to the advantages of brake, OD, fuel or ignition upgrades is a lost cause for some (maybe most), maybe an analogy that may help them understand? think of having rear discs like having a condom, better to have it, and not need it, than need it, and not have it...

Addition of O.D's, fuel injection, and rear wheel disc brakes, usually offer no real advantage let alone never pay for themselves.

Especially in hobby cars. It's more for bragging rights.

I enjoyed my cars when they were current, and more so now that they are rare and different.

I believe properly maintained drum brakes work just fine for someone that drives reasonably safe in the first place. They only fade after repeated hammering. Not really needed. Even on today's freeways. Most folks just drive way to aggressively today. Not to mention all the other things folks do while driving on those commutes.
My reason for swapping would simply be availability issues.

The above mention of crashed newer cars bares out this belief.
It's not the car so much as the nut that holds the wheel.

What did the Green Brick run?

11" drums in the back

How many 4 wheel disc brake cars did it beat?

You guys put what you want in your cars,but I already had to replace a 3/4 nose on my finished car because it didn't stop fast enough or straight enough. After seeing first had how much of a night and day difference they made on my friends 71 Charger R/T,I am upgrading all my cars.

If a car isn't stopping straight the problem is not the drums but the mechanic.

This is it exactly !!
And if you leave yourself enough room , someone will fill that safety zone you have created !

Both Chargers that didn't stop straight had disc brakes on the front.

Were they both red, because that will make them pull to the right.

Seriously,typical thread with opinions, or a tinge of https://en.wikipedia.org/wiki/Cognitive_bias or https://en.wikipedia.org/wiki/Confirmation_bias

To repeat, the OP asked "Is it worth It?" Not "are they better?"

I rest my case.

Really? Gee, I thought the cure for front drums was rear discs

I would hope you would be smart enough not to put rear discs on a front drum car, but I am beginning to wonder.

Bit of advice, find yourself in a hole quit digging.

Your forgetting the fact that properly sized and maintained drums actually work better.
Because they self energize.
It's repeated use or poor maintenance that is the difference.

Discs. need little to no maintenance per se and are cheaper to build.
This is why they are so prevalent today.

Is it worth the trouble or the expense?
Well that is a matter of opinion.
This thread has shown you what opinions are good for.

Too many other factors to blame it on not having rear disc brakes. This was what the OP was wondering.

I clearly stated atleast five times they are better,just saying!

I said there was significant improvement in the stopping distance and the straightness in which the 71 Charger R/T braked after the SSBC rear disc brake kit was installed and adjusted.

I stated that I saw with my own eyes,and personally experienced that two Chargers with disc brakes in front and drum brakes in the rear did not brake straight,and did not stop in a short enough distance. In the case of my own car,the rear brakes appeared to lock up about the same time,and left approximately the same amount of rubber on the road. The question by the OP was are rear disc brakes a good upgrade and are they worth it. I was stating that the Chargers were not four wheel drum brake equipped cars,I'm sorry if I really have to break that down for you!

"...worth it..." Hmmm...depnds on what you mean "worth"? "Worth" used as a noun? or adjective? or preposition? or even an intransitive verb? (archaic, you can rule the last one out).

Worth to whom? Me? No. I don't race on the street or track, and I don't speed or follow too close or engage in other forms of reckless driving. If a bus full of nuns pulls out in front of me without warning, best I can do is steer to miss 'em or hit the least bad obstacle, or probably just stand on the brakes. In my (drum brakes) cars, that will lock 'em up. What more could I do?

Posts like this are fun, cuz bring out all kinds anecdotes, conjectures, opinions, ridicules, "bad mouthing" and spirited discussion of all kinds.

For me to give the OP an opinion re his question, I'd have to know why he's even considering the modification and his financial circumstance. Basically, what is he buying and how much can he afford to pay.

or just review the second post of this thread.

For me it cost a lot more money to put a nose on a 70 Charger R/T than it does to buy a disc brake up grade kit. Just go watch some of the original roadtests of these cars that Bud Linderman did on Road and Track. I saw one on a 71 383 4 speed Challenger that the car went completely sideways under hard braking just like my friends Charger did.

Interesting conversion and good opinions for and against. Since the car I am building still has the original drum brakes, shoes (whats left of them) hardware etc everything will need to be replaced either way. I plan to drive this car a lot, and live around roads fun for spirited driving. I think since I have to spend a lot of money either way I will try rear disc on this car and keep the drums on the other one (all new system with NOS shoes, drums, hardware etc. (Plus I have several boxes of NOS shoes to support that car for a couple of centuries, plus another set of NOS drums)). I really dont mind the expense of the rear set-up, its a drop in the bucket compared to the rest of the build, I just didn't want to waste the time if no advantage is gained or even worse perforance (junky aftermarket systems etc). I appreciate the pros and cons on both sides, lots of great information on this site.

The reason the cars went sideways is because the rear wheels locked up. That is because they had too much rear brake.

The rear disc kits solve your problem by either being less powerful or they use a proportioning valve to adjust bias.

Kevin

There's really just two things you need to consider. Unless you go with a racing Wilwood type setup, which may or may not come with an e-brake setup, the factory drums are lighter than the factory type discs. The racing discs are rather small to fit inside a standard 15" wheel. If this car has huge tires on the back you might consider an adjustable proportioning valve to dial it in correctly.
1. Is un-sprung weight a priority?
2. Do you want to keep the e-brake setup?

Drums are an over complicated POS means of engineering (by comparison) to discs any day of the week. I'm not getting in to a debate on cost vs manufacturing on these dinosaurs. The fact is, if drums were more efficient, NASCAR, NHRA, F1, SCCA on and on etc. would run drum brakes. They do not and have not for many years.

What about big trucks??? Some bada$$ drums right there!

Heck I think 4 wheel disc is worth it just because I hate working on drum brakes.

I've never owned rear disc brakes, not even on my 9 second cars, but I sure do want them for my Duster.

If you re buying brakes for your drag car I highly recommend Lamb.

The good rear disc brake kits have working emergency brakes.

Who makes the best kits for Mopars.

Do you want to retain the factory axle adjustment, or go with Green Style bearings and eliminate the adjustment?

DrDiff IIRC has the only kit on the market that retains the factory adjuster, utilizes Cobra components

I personally have used several rear SSBC rear disc set up on 8 3/4 and DANA 60 axles, 15" rims are the minimum for clearance, you retain a parking brake, Green Bearings are required, utilizes Cobra components

either kit will work depending on what you desire, just be sure to research or ask questions to avoid any pitfalls when installing any mfg's kit

Thanks. I already have the Green Bearings for the car and plan to install them when I remove and restore the rear end. I plan to run 15" wheels on the car too. If the SSBC has a good system I will consider it, the front I installed from them appears to be nice quality, easy assembly.

If you go with the SSBC rear discs, their instructions leave a lot to be desired (unless that's changed?), seeing how the kit is somewhat universal in that it gives you a broad spectrum of adjustment/fitment, just remember to center the caliper's pads/opening on the center of the rotor, I've seen too often some individuals bolt the caliper directly to the axle tube flange bracket supplied in the kit without shimming it in a centered location as it sits on the rotor, this leads to premature inner pad failure, and poor operation....what rear end are you running?, do you plan on removing the thrust button in the 3rd member?

Many other variables to take into account: I generally try and design an ideal 70/30 to a minimum of 60/40 front to rear brake brake bias by choosing a set of rear discs based on what I'm running upfront caliper fluid volume wise as well as piston(s) diameter and pad/rotor surface area so I can avoid running a proportioning valve to limited the rear bias, I generally run the rearward line right off the master, and the front master line I'll "Tee" off for L/R, no distribution block, no proportioning block, generally I make most of my systems and customers systems power assist, running a dual diaphragm booster, if the engines vacuum can support it?, generally a stick car can get by with 8-10" vacuum, an automatic usually needs 15" vac minimum running a dual diaphragm booster to safely have repeated braking ability

As it has been pointed out already in this thread.

If you have properly working big drum brakes it will stop the car fast and straight the first time. And even the second time

Where the disc are better is on the repeated stops with hot brakes

My RT Challenger with manual drum brakes, 11 x3 front , 11 x 2 1/2 rear would stop the drag car no problem, fast and straight from 120 mph

I've aggressively driven a 4 wheel stock power drum, performance tired C body (as in drifting sideways on the highway at 140+) and an E body G machine with hydroboost assisted 13" discs with big sticky tires at 150+ that is run on road courses.
As long as the tires can hold the pavement, the brakes are fine. If the car skids - you have overpowered the tires and discs might give you better pedal feel but will skid the same tire just as easilly. Pretty simple physics there. Brakes can convert energy of motion to heat, but tires have to be able to manage that transition.
I agree with SuperC that most drum cars are not properly set or maintained. When they were being sold, four wheel drum cars were being adjusted 4-5 times a year and only driven 10K miles in the same time frame. I routinely have to readjust and balance customer's cars after driving them.
If your complaint is that your drum brakes lock up it may be your tires or an adjustment issue. Especially if the car turns as it brakes.
If your drum brakes fade from heat, you are using them too hard and should upgrade. Drum brakes are not good at repeated hard stops.
If you hit something and are in fear of hitting something else, pay better attention, think well ahead of where you are, slow down, or keep it parked. I assure you even supercars moving in parking lots hit stuff that pulls out in front of them. Impacts are not the result of a machine.

65pacecar, you got your moneys worth on this one!

I went 4-wheel disc from Dr Diff with the 13" Cobra front/rear kits that retain the parking brake feature.

Why?

Because a set of 10" or 11" drums wouldn't make much sense on a car with 18" wheels

Thanks. I am running a 8-3/4 with 3.91. I have not considered the thrust button, what is the advantage of removing? I am planning to run green bearings on this car.

It has been an interesting thread with some good information both ways.

Generally if you where replacing just the bearings over to Greens there's no need to remove the thrust button, but when you retrofit an aftermarket rear disc kit, the spacers (if any) supplied with the kit to replace/restore the thickness of the drum brake plates discarded, are not the same thickness, so this moves the axles inward loading the thrust button excessively, or may even prevent you from seating the axles/bearings/flange...

So you can either remove the thrust button from the 3rd member, or machine an axle/flange spacer that is of the same thickness of the brake backing plate your discarding if the spacer supplied in the kit is not adequate...

I myself prefer to retain the thrust button and machine a set of spacers as required to position the axles in their "stock" location if needed, it's going to depend on the kit supplier, but measure all critical distances/specs of where the axles sit in there stock configuration before letting the parts fly off

Mike

Thank you for the tip, excellent information. I Have access to a full machine shop, I can design any spacer necessary and have it machined to spec. I appreciate the advice.