How much advantage in adding rear disk brakes?

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harrisonm

harrisonm

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Many years ago, I installed a front disk brake conversion kit on my 69mBarracuda. It is one of the best mods I ever made. I am very pleased with the braking action in my car. I have often considered adding rear disk brakes, but I wonder how much of a difference it makes. Any comments from those who have done it?
 
Probably the biggest difference is how much easier it is to replace the disc pads vs drum shoes. All those springs in the drum brakes are a pain in the ***.
 
If you’re thinking about racing your Barracuda, here’s a dual caliper option for the rear.

DC07432B-0D36-4E1D-BD17-DB6D8CC48961.jpeg
 
I don't know.....I'd say it'd add maybe 20% more stopping power? Just a guess. I think post #3 summed it up well and he oughtta know.
 
If 80% or so of your braking is done by the front brakes, then you are only working with the improvement on the 20% of the rear. So even if the discs were much better than drums, the gains would be minimal.
They look better than drums behind big modern wheels but with original style wheels or Cragars etc you won't really see them.
Don't you need to convert to Green bearings as well with rear discs?
I've always liked the idea of discs all round, but I've left the drums on the rear for all the above reasons.
 
I think the reduction in rotating weight would be the best benefit. I have always believed that unless your doing some severe racing, the factory rear drums work just fine.
 
66 Sat said:
Don't you need to convert to Green bearings as well with rear discs?.
Click to expand...

there are kits available that uses stock tapered bearings when converting to rear discs in the 8.75 the Dr Diff kit comes to mind. A member @dodgedifferent2 fabricates a hardware kit for the sane application where you purchase his hardware and buy the rotors, calipers etc locally. That’s the route I used for my rear discs
 
It's also a MUCH cleaner operation to change pads vs shoes.

But as a performance improvement, very little unless used under extreme conditions like rally racing.
 
Maintenance is easier but I don't think drums are bad in the first place. There is much more surface area than disc brakes. I may be wrong but I think the biggest difference is in the driving feel because disc brakes don't retract as much as drums so the pedal feels tighter?

I have a 54 chevy 210 that I left as drums but removed the old brake pedal and under the floor master and installed a firewall mounted power brake booster and master. I reverse engineered the pedal assembly from pictures I found of a kit that is sold and was able to do it real cheap. That heavy beast will stop on a dime now with hardly any effort. It feels like a modern car.
 
IMHO
The only real benifet is the lack of self energizing that drum brakes have. I suspect that it would make locking up the rear more difficult thus giving you more stopping control.

That control MIGHT help you stop faster or at least be able to maneuver while panic stopping.

Still need a proportioning valve to fine tune it.
 
I have Wilwood disc brakes on all 4 corners of my bracket car. My car seems to be able to slow in a very controlled manner in order to make the second or third turn out at the end of the track.
 
MoparMike1974 said:
I think the reduction in rotating weight would be the best benefit. I have always believed that unless your doing some severe racing, the factory rear drums work just fine.
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ehhhhh....9 times outta 10 drums are lighter. That's why a lot of dirt track guys use them.
 
2 more wheels that can squeak during braking! I see no return of investment on rear disks.
 
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How are you driving this car? Yes the fronts are a big improvement on most cars, but if a street cruiser then not much will change with rear discs.

If you guys are having trouble with rear drum brake shoe changes on a rear wheel drive car then go buy the right brake tools, or go buy a new car with a warranty.

the dual calipers on rear for drag racing are great for holding it on the starting line when you don’t have a trans brake.
 
I havent done it, but like 66Sat said, if front braking is 80% then 20% is rear. If you gain 50% in the rear by swapping to disc then you have a 50% gain of 20%, which=10%. Not worth the effort/$$ in my opinion.
66 Sat said:
If 80% or so of your braking is done by the front brakes, then you are only working with the improvement on the 20% of the rear. So even if the discs were much better than drums, the gains would be minimal.
They look better than drums behind big modern wheels but with original style wheels or Cragars etc you won't really see them.
Don't you need to convert to Green bearings as well with rear discs?
I've always liked the idea of discs all round, but I've left the drums on the rear for all the above reasons.
Click to expand...
 
RustyRatRod said:
ehhhhh....9 times outta 10 drums are lighter. That's why a lot of dirt track guys use them.
Click to expand...
Can't speak for where you are but around here the only dirt track guys using drums are in entry level classes where the rules require it.
 
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