itsarebuild said:
In reply to Wicked93gs :
It’s not that drum brakes suck.... it’s that disk brakes are better. Sure parking brake setups may be easier and the setups themselves may save a few pounds, But there is a reason high performance cars and trucks run disk brakes.
Disk brakes are easier to cool, and they ave a linear actuation curve. Very important on the front of a vehicle and in racing.
On the rear, it's a wash. Personally, I prefer drum brakes because they don't need constant maintenance the way underutilized disks do. Replace the calipers every couple years because the piston mechanism seizes up, replace the pads and rotors every year because they rust all to hell because they never get hot enough to burn off overnight rust...
Drum brakes' biggest issue is they are hard for some people to figure out when you have to replace the shoes when they finally wear out after 200,000mi.
To the best of my knowledge, trucks still use drum brakes even on the front. Drum brakes have superior braking ability for their size, in part because of the self-actuation effect. They just don't cool very well, which is why truck drivers use engine braking for long decelerations.
From what I've read, certain years of Mazda 6 front brakes, I'm wanting to say 03-06, will fit on second generation Ford Probes for a good upgrade.
84FSP
SuperDork
2/26/20 10:14 a.m.
infinitenexus said:
From what I've read, certain years of Mazda 6 front brakes, I'm wanting to say 03-06, will fit on second generation Ford Probes for a good upgrade.
I think the guy on here pimping out a last gen probe did that swap on the cheap.
FYI, for anyone looking for large radial mount calipers, late-model Viper calipers are surprisingly cheap. Like $300/ea on Rock Auto for brand new Brembos.
In reply to NorseDave :
The Acura RL had radial mount four-pots too. Advics made them, and they are under $200 each.
Not quickly finding information regarding piston diameters.
Gingerbeardman said:
In reply to ZOO :
If you can find the data sheet for the caliper that provides displacement (piston size, number of pistons, etc.) then you can work backward from stock to figure out whether to upsize the master cylinder or downsize the master cylinder.
More fluid displacement at the caliper will require more fluid displaced at the master cylinder, but too large will result in a soft pedal or inadequate proportioning, too small will increase pedal effort and increase the pressure delivered.
There are a few brake gurus here who could probably give you a formula, I know that Wilwood used to have a decent calculator, but that link is dead when I bring up my bookmarks.
Hydraulics are just gearing or levers. Once you've made that connection, it all makes sense. Also, that gearing is all through the system starting with the geometry of the actual brake pedal. If you're only changing one thing, it's easy to figure the difference. And just like all gearing, you trade travel for mechanical advantage.
One easy mistake to make - if you're converting from a sliding caliper (pistons on only one side) to a fixed one (pistons on each side), you only use one side of the fixed caliper for your calculations. That's because they only move half as far.
iansane
New Reader
2/26/20 11:36 a.m.
Knurled. said:
In reply to NorseDave :
The big Acura (RL?) has radial mount four-pots too. They are one of the Japanese generic brake manufacturers (Akebono I think, but memory hazy) not one of the big European companies.
I'm pretty sure those aren't radial, just standard mounts if they're the ones I'm thinking of. I paired those to an audi TT rotor for a brake upgrade on one of my e30s. They were from some late model sporty acura.
In reply to iansane :
Sorry for the edit - I think better in hindsight than in the moment 
I'm 100% sure radial mount because I have worked on them, and it kinda blew my mind that Honda did that.
iansane
New Reader
2/26/20 12:05 p.m.
For the Koreans, its always been "go to the big fwd car and bold them onto the smaller car" option. the 01-06 Elantra had pathetic 9.9" front rotors and half of them had rear drums. The easy button was 03-08 Tiburon calipers and 04 Sonata 11"rotors. Tiburon you went XG350 rotors/calipers for a bolt on to get 12"rotors and 2 piston calipers.
Knurled. said:
In reply to NorseDave :
The Acura RL had radial mount four-pots too. Advics made them, and they are under $200 each.
Not quickly finding information regarding piston diameters.
Interesting. Would have never even looked at Acura for those, at least not the RL. Rock Auto says 2005-2012 RL, 43mm pistons, orig mfr is Advics (?). I wonder what sort of pad options there are for those.
In reply to NorseDave :
43mm square setup? That's cool for the swappers, a caliper can go on either side. Every Brembo caliper I have seen had staggered pistons, meaning the calipers are directional.
In reply to Knurled. :
Hard to tell from the pics to be honest. The Centric reman part just says 43mm. But it also lists a diff part number for L and R.
iansane
New Reader
2/26/20 3:08 p.m.
In reply to NorseDave :
Could be just a matter of fluid crossover vs bleeder screw location for L&R.
In reply to Keith Tanner :
"I'm more worried about the general concept that "bigger is better". "
Me too. From what I understand, bigger brakes don't necessarily mean shorter stopping distances.
I have been considering an upgrade for my Festiva which uses Aspire front brakes. Everyone says the car stops sooner. But I'm concerned about the extra weight, and it's unsprung weight, which may limit acceleration and stopping to boot.
Tires provide the traction. All the braking system can do is fail to take advantage of it. Single-stop distances are all about proportioning and modulation. Multi-stop performance is all about heat management.
If Aspire front brakes do help a Festiva stop shorter on a single stop, it's because they fix a proportioning problem. Or, more likely, they increase the brake torque so that you get more braking force for a given pedal pressure. Then they feel more powerful even if the stopping distance is unchanged.
Race drivers like a firm pedal and don't mind pushing a bit. Street drivers like a lot of torque even if it means a bit more travel.
I know for a Festiva you can swap on Aspire front hubs and rotors to get 4x100 and removable rotors that have an upgrade path and then bolt Opel Manta front hubs and rotors onto the rear to get the matching 4x100. I didn't work out the rear caliper bracket for the swap.
Any Fiero brake upgrade will bolt onto an Opel Kadett, GT, or Manta. Also a Chevette.
In the later years of the XJ Cherokee there was a one year only rear wheel cylinder that bolted in and was 1/8" bigger. That was just enough that the rear brakes actually did something but not enough to need a new master or proportioning valve.
Knurled. said:
On the rear, it's a wash. Personally, I prefer drum brakes because they don't need constant maintenance the way underutilized disks do. Replace the calipers every couple years because the piston mechanism seizes up, replace the pads and rotors every year because they rust all to hell because they never get hot enough to burn off overnight rust...
Drum brakes' biggest issue is they are hard for some people to figure out when you have to replace the shoes when they finally wear out after 200,000mi.
To the best of my knowledge, trucks still use drum brakes even on the front. Drum brakes have superior braking ability for their size, in part because of the self-actuation effect. They just don't cool very well, which is why truck drivers use engine braking for long decelerations.
I never understood the rear disc swap for a street car but people love to do it.
Drums are great. They work, they're cheap and last forever.
You should see the big brake swaps the Sonic guys are doing. Encore/Trax rotors and bracket with either 4th gen Camaro, or C5 calipers. And they have good brakes to begin with.
In reply to Keith Tanner :
One thing the first generation Volvo S40 guys would do would be to install some version of Galant caliper/rotor, because two piston vs. single piston. Or maybe it was Galant rotors (for the 4 lug) and Eclipse calipers.
I never understood that - the S40 had some of the best brakes I'd ever had. The brake pedal was firm and easy to modulate. The calipers, although single piston, were stiffer, and the OE pad compounds were way better, AND the rotors were larger! The calipers were a paperclip thickness away from contacting everywhere with a set of Lancer Ralliart 15x6 wheels. But they didn't have two pistons so clearly they weren't as good, I guess.
I never understood the Japanese fetish for soft mushy brake pedals. Subaru in particular used to get crucified on a regular basis for the crappy pedal feel.
