4 Piston Brakes???
 

My 91 N/A is a 5 lug car with single piston calipers. I already have the four piston calipers from another RX-7. Does it all bolt right up? I tried searching I couldn't get any concrete answers.

possible, take off the wheel on the 91 and check where the mounts are see if they mount up.

the calipers will bolt up u will just need the quad piston rotors..

I thought all rotors were the same size for S5.

there is a vented and solid disc available.. I would use the vented disc with the 4 pot calipers

I have both types of 91 car... 4 and single pot..

The both cars have vented front but the single pot car has non-vented rears.. the 4-pot car has vented rears....

The fronts will bolt straight over as long as you retain all of the caliper-side hardlines. The rears need the entire hub assembly to be swappe.

So the N/A front brake lines will bolt up to a 4 pot?

Yup.

The hard lines will... the rubber lines are slightly different in length.. you'll see what I mean when you hold them up to each other.

Sorry, you're right, keep the rubber pieces with the calipers, and just disconnect and reconnect from the brake tubing. I did it on mine, but it's been a couple of years, and I ended up having a mechanic finish the rears because I couldn't get the axle nut loose.
I took the center cap off and used a 24" breaker bar, and a 4 foot fence post over the top of that, and all I did was bend the fence post and lift the entire rear of the car off the ground. :D

Is the single pot 4 lug wheels?

I think the s5's were all 5 lug. I actually switched to the TII 4 pot calibers and rotors because it was the same price to upgrade the brakes AND get new wheels as it was going to be to get the same wheels as 4x114.7 with that offset. :D

sorry to dig up an old thread, but i'm in the middle of doing this... brake rotors in the front are the same for single and four piston, correct? but i'll need the flexible brake lines for the four piston brakes....

Thanks, this info is helpful to me too

The front 5 lug rotors are all the same, you don't need to change them. You do need to change the rear rotors, but if you've already got a 5 lug car then no hub swap is needed. You can use single piston brake lines with 4 pot calipers if you don't use the caliper hardline, it fits perfectly.

Since we're on the subject. What exactly has to be done to swap the rears. I thought all you needed were the rear calipers and rear vented rotors, and brake lines. What else would I need?

Brake lines are the same from vented to non.

All you need are the rotors and calipers but to be honest, I doubt you'll be able to tell any difference.
If your current non-vented rears work OK I wouldn't bother.

You need the different caliper brackets too, the part that holds the pads, the vented one is wider.

Hate to resurrect this thread, but if I started a new one I would just get "Search noob, this has been asked a million times!" Well I did search, and found half of what I needed to know.

I have a 4 lug s4, I just got a 5 lug swap (just hubs/spindle) from an 89 base (5 lug, single piston front, solid rear) and I got the 4 pot fronts from someone on this board. According to this thread I can use the front hub I got with the 4 pot with no problem, just need the 5 lug vented rotor.
For the rear, I would need to get a different bracket if I wanted to use the vented rears (according to my searching and the above post).

On to my question, would my 4 lug rear calipers bolt onto the 5 lug hubs/brackets and work with the solid rear rotors, or would I need to get the caliper from the 5 lug base with solid rotor? I don't want to have to source out the brackets for the 5 lug vented if I can use what I have.

It looks like the solid rear brakes were the same size so I think you should be fine to use the S4 stuff.

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/specifications-what-did-2nd-generation-rx-7-come-w-options-standard-features-642372/

Just so your clear, if you wanted to use the rear vented rotors you need to change the bracket AND the caliper.

Thanks, that's what I figured/hoped for. I checked Advance Auto and the dimensions were the same, so I ordered the solid 5 lug rotors and will probably be doing the swap this weekend, so I will post back with a definite answer.

your good to go imo. my 91 had single piston brakes on it, i threw 4 piston brakes on it without changing the rotors. If you dont have the brake lines already for it, you can just get some stainless steel braided lines if you like while your at it.

i'm pretty sure the 4 lug S4 and the single piston S5's have the same rear brakes except that the S5 is 5 lug, instead of 4.

just order corksports single piston brake lines for use on the four pots.. you will love it!!

I got 4 pot fronts to replace my singles back when I first got my 89 GTU. They bolt right up. Rebuilt them, bought new rotors, installed ss brake lines in place of rubber, and got some better pads. Might as well do it all. Rears stayed the same. Changing up rears didn't seem worth the trouble beyond the SS lines and new pads.

Those 4 piston brakes possibly saved my life last sunday! I hit a deer on the interstate but if it weren't for those brakes i would have hit it A LOT faster.

Just to follow up, my 4 lug rear calipers worked with the 5 lug solid rotors, no issues.

Also went ahead and replaced both tie rods, ball joints and got Corksport SS brake lines.
Went with advance auto rotors and Hawk HPS pads.
Getting tires and alignment this week and I'll hopefully be ok for a while.
New struts/springs are next on the list. Followed by poly bushings.

I have an s4 4-lug base model. Single Piston caliper fronts, non-vented rears. I'd like to get 4-piston front calipers and vented rear discs but I don't intend to do a 5-lug swap since I like my rims.

Will the 4-piston calipers bolt on to my spindle? Are the rear calipers for the vented rotors different in any way other than the wider bracket and will they bolt? And do I need to change my master cylinder as well?

I looked in the forums and this thread is the best for this topic I think.

All the base models for S4s and S5s had single piston calipers but one is 4 lug and one is 5 lug, so the knuckles should be the same right? Whether 5 lug or 4 lug.

See Aaron's how to: http://www.aaroncake.net/RX-7/4lug4potbrakes.htm

I'm also looking to do this next... But only in the front. Is there even a 4 piston rear caliper option? I thought all the rear calipers were the same.

Also would anyone have feedback or comments on pedal height after conversion? And would a new master cylinder ever be needed?

I was wondering this and checked Mazdtrix. They differentiate between ABS/non ABS and AAS/non AAS, but not between 4 and single piston front calipers. I think that it's simply the fixed calipers have pistons 1/4 the area of the floating units, or the pistons are slightly larger and the reduced flex compensates for the increased pedal travel?

The idea with 4-pots, aside from the cred and sex appeal, is that there is more mass to draw heat away from the rotors and pads. And to prolong the boiling of the brake fluid. A DD won't need them. Even an autocross car probably won't need them. But Ryouske Takahashi and someone who tracks the car would need them. But...since when is Rx7 ownership about need? :)

Oh, the rear calipers are different, but identical aside from width. The vented rotors are thicker and the caliper integrates the parking brake, so they need slightly deeper calipers for the vented rotors.

Sorry, Glory, but I disagree with most of this.

The FC's "soft pedal" is the result of design specs and tester preference, not caliper flex. Even FC's originally equipped with the 4-piston calipers exhibit what many (myself included) consider a "spongy" pedal...brakes work fine, they just don't "feel" like it.
A bigger booster/MC combo can fix this.

The "idea" with 4-pot calipers is greater and more even clamping power on the pads, not heat dissipation. The larger and more enclosed caliper body is actually worse than the single piston slider caliper in heat retention (but you are correct that this is all moot in a street car).

I am having a heck of a time finding the right rotors for mine for some reason. I picked up these duralast PN: 3194 and the flathead holes are not lining up with what I have. The ones they are sending me are 1 3/8 from outside of each hole (Flathead edge to lug throughhole outside edge) and the ones that I need have 1 5/8 space between them. I know they introduced abs in 87 or 88, My 86 GXL does not have abs, but has the AAS and 4 piston calipers. My car sits on jackstands until I can figure this out. The hubs seem to be shiny, like alluminum- could they be aftermarket and thats why these parts arent fitting?

Mine didn't match up either. I just went with it. I don't think the screws are that important.