[Lifetime Goat]

Its that time of year and looking to make the GTO better on the street. If I upgrade to a new Baer or similar 4 wheel disc system will the stopping power vs the original disc/drum combo be worth the effort? If so who has the best choice for a 1971 A body. I already have 17 inch centerlines do there is plenty of room to upgrade.

[1968GTO421]

The GM single piston caliper has alot of after market upgrades for it and I've seen upgrades for the drum brakes in back. So for street driving I feel that the existing system can be upgraded easily and inexpensively enough. My '68 was changed to a 1970 diisc brake system in front by a previous owner. In back I may go with a Ford 9" rear end and upgrades for that are cheap enough.
A lot depends on your use for the car. If you're thinking of auto-crossing it tha change to Baer can be justified easlly or if you live in/near the Poconos and do alot of mtn driving the four wheel disc can be your friend. In the end rhe decision is yours.
JMHO

[Steve C.]

If keeping the rear drums, and you haven't already done modifications, there are good alternatives . Cryo treated, high friction linings, etc. Complete kits.

One source, with others out there....

https://musclecarbrakes.square.site/


.

[Slick]

Originally Posted by Steve C.

If keeping the rear drums, and you haven't already done modifications, there are good alternatives . Cryo treated, high friction linings, etc. Complete kits.

One source, with others out there....

https://musclecarbrakes.square.site/


.

One possibility is '73-'77 A body wagons that had 11" rear drums.

[JLMounce]

How is the car actually driven? Drum brakes don't inherently stop worse than disc brakes. What disc brakes do a whole lot better is dissipate heat. That translates to repeatability.

If your car never sees repeated hard braking like in a spirited drive through the canyons or an auto-x, switching to disc brakes may not actually provide any better stopping power. If your system now can lock up all 4 tires, going to 4 wheel discs alone is unlikely to produce better stopping distances. Not unless you're also upgrading the stick from your tires.

There are a couple considerations however that you may be looking at when changing to discs. Many disc brake setups using aluminum calipers will shed weight off of a drum setup. This is both reciprocating and unsprung weight, both of which do offer performance advantages not entirely related to stopping distance. There's also the aesthetic appeal. If you have an open spoke wheel design, having disc brakes and nice calipers sitting in the hoops arguably looks better than having a drum in there.

If you decide that you want to look, that alone is worth the upgrade in my eyes. For a budget friendly approach, I like the stock GM 11" rotors with D52 caliper mounts in the front and D154 caliper mounts in the rear. This is the standard kit you find all over the internet. Then instead of using the factory single piston iron calipers, opt for the Wilwood D52 and D154 replacement calipers. For a minor increase in cost, you save weight, get better pedal feel through stiffer calipers, and save weight. They also look much better.

[carbking]

Originally Posted by JLMounce

There are a couple considerations however that you may be looking at when changing to discs. Many disc brake setups using aluminum calipers will shed weight off of a drum setup. This is both reciprocating and unsprung weight, both of which do offer performance advantages not entirely related to stopping distance.

Or go to aluminum drums (if available). Pontiac used some aluminum drums, and I have a set on the rear of my '74 GTO. Do not know what might be available for your GTO.

And yes, it did save several pounds.

Jon.

[vertigto]

For a budget minded conversion, check out the Right Stuff kits.

[jerry455]

I upgraded the brakes on my 1976 Firebird. Stock rear was a 9 1/2" drum with an 11" front rotor. I added the 1973-1977 Lemans 11" drums to the rear and a 12" rotor to the front. The front was easy with a 1977 0r newer B body wagon front spindle and a 1LE rotor. These rotors were used on late 80's and early 90's Camaro and Firebirds. It was the same wagon rotor only with the 4 3/4" bolt circle instead of the wagons 5" bolt circle. I don't know the exact difference in braking, but it definitely feels like it stops better.

[Lemans64]

First off what are you doing with it that you feel you need to improve on the braking? My 64 stops very well with 69-72 front disc and stock rear drums.
Running a hydroboost so maybe making more pressure than you have? Is the dollar value worth the possibility of braking better than what you have now?
Just my 2 cents.

[tom s]

IMO,for a true street driver,brake upgrades on my 69 Bird was a waste of money.Tom

[imposter]

i have a full set of wildwood 4 wheel discs for sale les than 1000k miles

[Scarebird]

To the OP; in short, no.

The factory 11" setup is good; best thing you can do is run a set of premium pads like Hawk or EBC. A bodies are not known for racing prowess where turns are considered.

I ran my Trans Am before Covid at Sandia Raceways in a weekend class. Other two classmates had late teens Camaro and Corvette with stock suspensions with LT1 engines. My LS3 powered TA has 1LE front rotors with stock calipers with Hawk pads and our drum-in-hat rear setup with S10 rotors and Citation calipers.

Car was pronounced very well-balanced after a drive by the instructor.

The Camaro only bested me once - I drove my Pontiac hard, and the Corvette was driven timidly. This setup was adequate for a 3,350 pound TA with manual master driven on a track in anger and is easy on the street.

TBH the best improvement was the Delphi steering box.

[Schurkey]

Another vote for 11" drums instead of rear discs. Dirt-cheap upgrade from the 9.5" drums.

Zero problems with getting the park brake to work properly (assuming the cables are in decent condition.)

The 12" rotors in front are a good idea if you can find a friendly Treasure Yard with the steering knuckles. I'm still looking (but not very hard.)

[Lifetime Goat]

Thanks for all the good feedback. I don't drive frequently but when I do I run thru the gears. Based on these comments I am gonna start with what I have and upgrade the pads and rear drums. Thanks all.

[The Champ]

Originally Posted by JLMounce

There's also the aesthetic appeal. If you have an open spoke wheel design, having disc brakes and nice calipers sitting in the hoops arguably looks better than having a drum in there.

This was a serious reason for adding rear disc brakes to my wife's '72 Camaro after we upgraded to her current Billet Specialties 17" wheels from her previous 16" Centerlines.

The Centerlines - you didn't really see the rear drums. But with the BS Win Lites, the drums stood our like a sore thumb in my opinion. The photos below show it with the original factory front disc/rear drum.

We used The Right Stuff rear disc kit and then ordered front disc/rotors to match the rears.

[The Champ]

Close up shot of the new fronts - sorry, no closeup of the rear.

[JLMounce]

Originally Posted by jerry455

I upgraded the brakes on my 1976 Firebird. Stock rear was a 9 1/2" drum with an 11" front rotor. I added the 1973-1977 Lemans 11" drums to the rear and a 12" rotor to the front. The front was easy with a 1977 0r newer B body wagon front spindle and a 1LE rotor. These rotors were used on late 80's and early 90's Camaro and Firebirds. It was the same wagon rotor only with the 4 3/4" bolt circle instead of the wagons 5" bolt circle. I don't know the exact difference in braking, but it definitely feels like it stops better.

When you upsize rotors and shoes, you gain leverage and with it braking torque. This will typically mean that all else being equal, a given amount of pedal travel will produce more braking torque than previously.

Overall braking performance however likely is the same as you had. It's the tires that are able to make the change in overall braking performance. It's true you may like the feel of your upsized brakes better, but you'll just lock up the tires with less pedal travel. Your 60-0 will typically be nearly the same.

One thing this does is decrease the amount of modulation you have with the brake pedal. It's one of the reasons you often see cars dedicated to auto-x and road racing utilizing manual brakes. The pedal throws are typically longer, which gives you better modulation.

[Formulajones]

A lot of people like that sort of thing these days. I don't really care either way.

We daily factory power disc brake/rear drum setups and it's perfectly fine. About the only advantage in a swap like that for me would be easier maintenance down the road, but it's not like I have to dig into the rear drum brakes very often anyway so

The biggest brake upgrade I made on a couple other cars is switching them to hydroboost. Much less pedal effort even over the vacuum boosters I removed.

[grivera]

My 64 Lemans has Ford 11" rear drums and a disc brake conversion up front with slotted discs - and it's a manual brake system. It stops surprisingly well and I have no intention to convert it to power brakes.

[geeteeohguy]

Originally Posted by Scarebird

To the OP; in short, no.

The factory 11" setup is good; best thing you can do is run a set of premium pads like Hawk or EBC. A bodies are not known for racing prowess where turns are considered.

I ran my Trans Am before Covid at Sandia Raceways in a weekend class. Other two classmates had late teens Camaro and Corvette with stock suspensions with LT1 engines. My LS3 powered TA has 1LE front rotors with stock calipers with Hawk pads and our drum-in-hat rear setup with S10 rotors and Citation calipers.

Car was pronounced very well-balanced after a drive by the instructor.

The Camaro only bested me once - I drove my Pontiac hard, and the Corvette was driven timidly. This setup was adequate for a 3,350 pound TA with manual master driven on a track in anger and is easy on the street.

TBH the best improvement was the Delphi steering box.

THIS^^^^. As a retired automotive professional with 42 years in the business, this is absolutely true. IMO, rear disc brakes are especially wasteful, and usually have inferior parking brake operation compared to drums. 4 wheel disc brakes are great on a road race track, that's about it. Without ABS, a locked wheel is a locked wheel. A GM factory caliper will do it just as good as a zillion dollar Wilwood caliper that needs 24" wheels. Both my GTO's and my old solid axle 'vette have 4 wheel drum brakes and they work just fine for me.