I wasn't sure what forum to put this in

What is the reasoning behind converting the rears to disc brakes on older vehicles that are mainly street driven?
It seems like an unnecessary expense that doesn't make sense to me. If one is going to the road course OK, but otherwise ?

Likely worth it for high speed driving and repeated stopping as drum brakes tend to not work as well when they don't have a chance to cool down.

My brother added them to the rear of a low 11 second street/strip car, and at the track it stops no better than it did with the drum brakes.

Just one of the things you have to do for a top dollar car.

Perhaps the system he added/design was not properly biased? perhaps the pad material chosen was inadequate for the intended application?, perhaps the master was under/oversized? etc/etc/etc lots of variables....when I design a 4 wheel disc brake system I design it for the intended vehicle, it's intended usage, I research the components so they meet/exceed the requirements as well as being compatible with each other, I test the system so that it meets the pressure and bias that I need before it even hits the street/track/course ....a properly designed 4 wheel disc system is a "day vs night" driving experience....


I've dealt with too many customers over the decades who used a "bolt on" a 4 wheel disc system only to say "I notice no change" or "it's worse than my 4 wheel drums" or experience pedal height/pressure issues or other assorted maladies.......when I done with a customers vehicle they get a pants sh1tting stoppable ride of their life that a quality designed 4 wheel disc system can offer, it's nice to stop as fast as you can accelerate, whether it's on the street or track/course


MikeG

I did it thinking it would improve regular driving safety.
Used an old TSM kit I had purchased a while back, but never used on another car.

While it wasn't that bad expense wise due to how long I had it, I would say it does over complicate things and it was a pain to install.
but part of that had to do with the caliper choice and needing to keep the parking brake.
If I had it to do over again, I would have just redone the drums and left it alone.

it isn't any better or worse, but the aggravation of the install could have been saved.

The only bonus is pad replacement is way easier than rebuilding drums.

I used just a basic system with stock pin type brakes on the front and Wilwood Dynalites on the rear. I love the pedal feel with this combo and a 1 1/16" master cylinder . When I press the pedal soft it stops soft and when I nail it they will pull it down fast. The unsprung weight of the Wilwoods is is about half the weight of the 11" drums. You do have to do the math though for the system to work correctly. There is a chart on the Mark Williams site on choosing the proper master cylinder. I was lucky I had a few different master cylinders on the shelf and found the one that worked great.
I made the switch when I was going rounds with 4 drums and it was getting dicey when hot lapping during time runs.
https://www.markwilliams.com/braketech.html
Gus

One thing that I have noticed over the years is that a lot of people assume that brakes are brakes. The same people who would not pick a random set of heads or camshaft for their engine will bolt random brakes on their car. The brakes need to be selected with as much care as the camshaft. The caliper bore sizes need to match the weight distribution of the car and the master cylinder bore size needs to match the caliper bore size. It is a hydraulic system and all of the piston sizes need to be carefully selected for correct operation. Most of the people I talk to have no idea what the piston size is in their calipers or the master cylinder. They just bought some cheap parts off the internet and bolted them on.

My takeaway then, if they ain't complaining, they probably didn't need rear discs performance wise in the first place, so no real harm evidently.

Rear discs even on the rear is seldom needed. For example, when is the last time in street use do you ever remember even smelling your drums from repeated hard brake use?

4 wheel disc IMO found OEM favor mainly in their better application in ABS systems, the weight decrease was a side benefit.

Back before 2006 I was a dealer for TSM. I did a real cheap group buy. Most tgat bought them bought used Caddy calipers at junk yards to trade on as cores on rebuilt ones. As that was a major cost. Unless you use non parking brake GM fronts on the rear.
I know FEETS (Kevin) did well and kust resealed used ones with no problem g or years.
You have to set the park brake on regular basis to keep them adjusted.

I still have a set it 2 here but am goiing to use them. Would go with the Jeep inside the rotor brake shoe type instead if I was buying a set up over TSM. Only reason I am going to use the 2 set ups I have is I have them

Truth. A properly speced, installed and plumbed 4 wheel disc system is waaayyy better than any drum brake deal.

Put them on a little front, big rear tire drag race deal, where the rears have to do 80% of the stopping, and it really becomes a no brainer.

On my 51 it has non-self energizing and non-self adjusting drums. Rear discs would be an improvement even if it added no additional braking ability.

You have to consider the whole package.

Anything would be an improvement on those LOL, try a 39-41 ford setup sometime r even the 59 dual wheel cylinder setup on mopars

My question was was more towards 60's & 70's STREET DRIVEN cars that rarely if EVER see any track use.

You mean a 51 with a FH six with 7.00x14 Bias tires single MC "whole package"?

The most cost effective stock type brake setup for a Mopar musclecar would be the 11.75 late model disc brakes up front with the big 11 x 2.5 drums in back. Now that Doctor Diff reproduces these parts it is also a fairly easy install. There were a few years where the 11 x 2.5 rear drum brakes were a little hard to find. Even the front 11.75 setup started to get hard to find but now Doctor Diff is reproducing the tall caliper adapter so that helps a bunch. The last B body project that I worked on went with big drums and big discs. It is a nice package that fits under 15 inch wheels.

On my Duster I went four wheel disc brakes using 13 inch rotors and 17 inch wheels. But that was more of a "statement" car. A budget build, or a more period correct build, would more likely want the big disc/big drum combo.

Nope, try again.

I'm using four wheel disc brakes on my under construction 1940 Ford Tudor street rod, I like to be able to stop well when needed
it has a Mustang two front end with a Lincoln Versialle(SP?) 9 inch stock rear end with all Ford stock parts, I hope it works well

If you don't have any experience with the stock rear brakes, read up on them. The pistons have a narrow range where they work. If you drive the car much you should be constantly adjusting the rear pistons.
Otherwise they run out of travel and don't work!

IIRC, the adjusting is done by using the parking brake regularly. Just get in the habit of always applying it when parking and you should have it covered.

Thanks, I'll keep that in mind.
I do use the E brake every time I can think of it in all my vehicles except the S/P Car, it doesn't have one. Park only with a line lock

Street rods are in a different category IMO. I built my 38 Ford over 30 years ago. Mustang II front, 8" ford out back, single reservoir stock master and it has always stopped extremely well even without power assist. The next time I change the master I'll likely up it to a dual but other than that I don't see any reason to upgrade anything else.
We did the same setup on my brothers 48.
If I were building them today I would possibly do some things different but what's there is working fine.

And just in case anyone's wondering, mine has a 340 Sixpack (mechanical DC carbs), His has a 360, both with 727's