Any of you guys convert front drums to discs? 72 cutlass supreme convertible. If I have power brake cylinder do i still need to swap it out? I would like to eventually. Unsure of positives or negatives.

 

I would not unless you do ALOT of autocross type driving. Drum brakes in good working order suffice just fine on a street car. Spend your money on the shiny stuff.

tc

 

I have the factory 4 piston caliper (1967 and 1968 only) front disc brakes on my 1967 442. I am very happy with the stopping power, straight and true. You shall have to change the master cylinder as the disc brake caliper requires a larger reservoir section. I see you are a new member and probably not acquainted with everything here in the forums. Our tech editor has posted a "sticky" on this very subject in the Tech Editor's Desk section which is well worth the read.

 

But…but…but….discs are better!!!!


Disc brakes dissipate heat better, assuming everything is adjusted and in good condition there won’t be a huge difference in stopping distance on a single panic stop. Multiple panic stops, or auto cross as you mentioned is where discs really have the advantage.

If disc REALLY stopped better, big trucks would use them.

 

I agree with the above statement.
I did my 68 4 drum using a donor 71 disc/drum car. So I was able to strip all the little parts. I put a later 71+ disc master cylinder on it. Never installed a proportioning valve or the correct regulator valve. Didn't notice a significant increase in braking maybe because I didn't install the proportioning valve. Always stopped just fine.

If you decide to do it anyway get everything off a doner car if possible, thou I believe it's all reproduced now.

The hose-to-frame brackets are different the knuckles are different and you will need the 72 disc proportioning valve as I believe it's still just a distribution block in 72 with 4-wheel drums.

I just redid everything to include the correct master regulator and booster. Havent bleed or road-tested yet. Not planning on a big difference this go around other than a visual impact with the correct parts.

 

I’ll buck the tide here. In my experience there is no comparison between front disc vs drum performance. Will front drums get you by? Absolutely. Cars had them for a century and trucks still use them. It sure helps if you use quality parts and know how to adjust them properly, so the pedal is good and it stops straight.

Stop from high speed or repeated heavy braking, go through a big, deep puddle? No comparison, discs hands down. It’s a really bad feeling when the harder you push, the less the car slows down from high speed, or wet brakes just do nearly nothing. Been there and done both. If I bought a 4 drum car, a front disc conversion would be towards the top of my “to do” list.

As noted, make sure you get the correct components if you change to discs.

​​​​​​….

 

The above reminded of my brother-in-law telling me about his ‘68 GTO with 4 wheel drums. He had to panic stop and said the brakes worked fine from 90 down to 50 or so, then they faded out and left him scared to death. After that I helped him install front discs.

 

Unless you do a bunch of panic stops. Then drum brakes work just as good

 

I had a 58 olds with 4 wheel power drum brakes and it was my daily driver for 4 years and never had any issues whatsoever

 

bccan...Bucking the tide is encouraged to induce a good convo, thank you. You are stopping a BTR engine you need BIG BRAKES at the big end lol,

If one is road-coursing with hard repetitious brake use....disc all day for the cooling recovery and (hopefully) increased brake surface area. Daily street driving...minimal improvement unless you're coming down the donner summit on your daily commute.

Aftermarket modern-design disc assemblies are superior. The 50-year-old stock stuff exhibits marginal improvement....IMO... That's IMO with no scientific data to back it up just experience over the last 40 years. Let's not belittle Detroit for the step forward from drums to disc. They did science for sure.

The SSBC, Wilwod, Brembo, Baer etc systems have plenty of science/modern design under their belts and are the way I'd go if I wasn't concerned about originality and was looking strictly for performance.

I'll have more to add after I see how the restored correct OEM system does in the 442.

 

I am going to add to my previous post (#3 above). With disc brakes you will not experience brake fade especially in a panic stop situation! That sick feeling when you stomp hard on the "good" drum brake equipped car and the wheels lock up and you slide into the rear of the car ahead of you! It only takes ONE panic stop like that to convince you of the benefit of disc brakes. When I was learning to drive in the 1950s, the mantra was allow one car length of distance to the car ahead of you for every ten miles per hour of speed; with today's disc brake equipped cars and better tires the accepted norm seems to be allow three or four car lengths to the car in front of you regardless of the speed!

 

Even with disc brakes you need distance but drivers still seem to rear end people

 

Better brakes don't help it you are staring at your phone.

 

Point well taken, at the end of the day it comes down to whatever makes you feel more comfortable. I love my drum brakes