Carrera Brake caliper swap

[niall]

Hi

Are 3.2 carrera brake calipers better than the mid seventies calipers found on the 3.0 carrera.
If I changed to these calipers would I need to fit the 24mm carrera discs and if so do both calipers and discs fit the 3.0 carrera hub.

Thanks for the help
Niall

[175K911]

Not all Carreras will work. Porsche changed the brakes for the '86 model year. Changes included:
Front rotors changed to 24mm width, calipers widened to work with them
Rear caliper pistons changed from 38 to 42mm.
Brake proportioning device inserted in the rear brake line to limit pressure to the rears under hard braking.

Is it worth it? The thicker front rotors don't heat up as fast. And the bigger rear pistons allowed the rear brakes to have better bite in normal driving. But the brake pads are still the same size.

If I didn't already have those brakes on my 86, not sure I'd do it unless I got all the parts and it wasn't too expensive.

[Bill Verburg]

Originally Posted by niall

Hi

Are 3.2 carrera brake calipers better than the mid seventies calipers found on the 3.0 carrera.
If I changed to these calipers would I need to fit the 24mm carrera discs and if so do both calipers and discs fit the 3.0 carrera hub.

Thanks for the help
Niall

As 175K911, you get a little better control of heat for track use.

The MY84 up Carrera(wide-A) caliper is the same as the earlier A calipers w/ an additional 4mm spacer between the 2 halfs. It and the 24mm Carrera rotors bolt onto earlier hubs w/ out any issues.

If you do this it's best to just do the front, that's where the heat issues are, and you don't change the native brake bias of the car.

If you are really into track days, it can be useful to add the thicker Carrera rears too, but then you will also need to add a p/v. An adjustable one would be best for that.

[KTL]

Niall,

Short answer to your first question is yes.

Long answer: All Carrera front calipers are the same. The wide A calipers on the 84-89 Carrera uses a 24mm rotor. The pistons in the A calipers, for any A caliper from 76-89, since their inception have always been 48mm diameter. Bill Verburg has assembled a very handy cheat sheet. See the second chart

http://www.pelicanparts.com/MotorCity/wmv/brakes.htm

The S calipers used on the Carrera 3.0 are less desirable from a functionality standpoint since they are alloy and have been said to flex under heavy braking. The iron A calipers flex less.

The S caliper also uses the 20mm thick rotor, which would be a negative (for track use) compared to the greater thermal mass of the 24mm Carrera rotor. The S calipers are also very expensive (when they were new).

The only upside I see to the S caliper (besides maintaining originality) is it's light weight. It would be ideal on an autocross car to use the S caliper and lighter, thinner 282.5x20mm rotor.

Long answer to your second question: If you changed to S calipers, no you do not need the Carrera rotor. The rotor native to the S is the 282.5 x 20mm rotor used almost exclusively from 1967-1983 on the front of the 911. You'd have to shave brake pads if you did want to use Carrera rotors. Both the Carrera caliper and the S caliper will fit your wheel hub and strut. The correct way to match the two calipers in question with the correct rotor is

S caliper + 20mm rotor
Carrera caliper + 24mm rotor

edit....... Bill beat me to it!

[Eric_Shea]

I love S-Calipers.

It always good to step back when contemplating something like this and ask why?

If you car is light enough, I'd stick with the lighter components. Why did Porsche move up? As the cars got heavier the brake became bigger.

All good answers here and all, for the most part correct. The change to Wide-A did occur in MY84.

I'll be like Kevin with a twist.

The only upside I see to a Wide-A is the heat dissapation of the larger (and heavier) rotor.

The sad thing is, Porsche has ensured that most 911 owners never have had the luxury of complaining about brake fade.

It sounds like you already have all the components to drop S-Calipers onto your struts considering that you have the 3.5 spacing of the S, A and Wide A-Calipers. I've never experienced flex with S-Calipers. Virtually every car in the 2.0 Challenge has them. I go out to Miller Motorsport Park and watch those guys with a 4.5 mile grin on my face.

The only problem is... "There is no such thing as a bargin S-Caliper". We restore them and I can't tell you how many guys buy a pair of S-Calipers for the bargin basement price of say $300.00 only to find out that all of the pistons are rust pitteded (95% of them are). The cost to replace those is hovering around $200.00 (check you friendly local host site).

Most at this age will need to be refinished. Just like out beloved Fuch's wheels, these calipers are properly anodized. To refinish them properly means 1) de-anodizing, 2) polishing and 3) re-anodizing. The re-anodizing part can be tough because there is now a steel post (knockback mechanism) that wasn't there the first time these were anodized. These were pressed in post factory anodization. Steel and anodizing don't mix. Two solutions are to machine the post out (they're not really needed) or keep the integrity of the caliper and mask it. Most shops will not take the masking risk with steel in their tanks. Bottom line... add another $300 to have them finished properly.

All told the $300 bargin becomes a $800-900 pair of calipers... well worth it though!

[PK Dorki]

Reviving an old post. Does anybody know where one can get the 4mm spacers to convert front SC calipers to Carrera calipers?

[Eric_Shea]

Best to just get Carrera caliper cores as you will nto only need the spacers but the NLA, longer 9mm Ribe fasteners that come with them. Again, ask yourself if you want or need that extra weight in rotating mass, the worst place to add un-needed weight on a car.

[911pcars]

Originally Posted by KTL

Niall,

"............ You'd have to shave brake pads if you did want to use Carrera rotors. Both the Carrera caliper and the S caliper will fit your wheel hub and strut. The correct way to match the two calipers in question with the correct rotor is

S caliper + 20mm rotor
Carrera caliper + 24mm rotor

To fit a 24mm wide Carrera rotor inside an S caliper, one would have to machine the caliper for the needed rotor clearance. However, you don't want to remove more material from this caliper, especially in the bridge area.

Best to go with plan B.

Sherwood

[PK Dorki]

911pcars - not interested in the S calipers--the SC calipers (identical to the Carrera calipers except the spacer).
Eric - thanks. It's for a Carrera, with a great deal offered on SC calipers (I'm looking for a spare set of fronts for racing).

[Eric_Shea]

Spacers would be 11mm as well. 7mm on SC A-Calipers. Again, if this is for a Carrera, best to just find a set of Carrera versions.