I have a 1985 928s automatic, it has the small rotors and calibers... is there an easy way to upgrade the brakes to nice large rotors, calibers? so it will stop like a modern day sports car? plus look better.... I don't want a crazy project, but is there a kit that goes in place all done?
thanks

 

S4 brakes/discs with adapter brackets is a good start then onwards and upwards at more $$$'s.

 

Your brakes may not look big, but they are more than adequate for the performance of your car. If you are not happy with the stopping power, start with new pads, that can make a world of difference.

Over the years many 928's have been successfully tracked / raced with the exact same brakes you have without issue. When I upgraded the brakes on my 81 for track duty, I upgraded to "S" brakes, the same as you have. Also make sure your brake cooling ducts are in tact.

Now, if you just want to go big for looks, nothing wrong with that at all. But as for stopping power, the S brakes are more than adequate.

 

Some people go for the S4 booster as it offers more assistance.

 

I suggest replacing your brake lines with braided steel lines ($100 or so from Roger www.928srus.com) then bleed the system well. I mean bleed it well.
Assuming your other systems are good (master cylinder, rotors and pads, and shocks) you car will brake better than most on the road today, and with a very firm pedal.
-Jason

 

S4 brake conversion...includes 86.5 as they are same as S4.

Rears are direct substitution.

Two ways to do fronts. Replace all front suspension parts from donor car. Or, acquire a pair of billet aluminum adapter mounts to adapt s4 calipers. You might need the larger s4 dust shield too to accommodate larger rotors.

I did a pretty good write up of former, swapping 86.5 suspension into 84 euro, which is essentially same situation as swapping into 85 usa. Will see if I can find link, I think it was on pelican due to rennlist having interface issues at the time.

Latter way, adapters, didn't appeal to me for such a critical application for various reasons. They say it is much easier.

Ultimately, it was a far more grueling process for me than it was worth. I did feel comfortable when I sold that car, though, it was safe.

I drive 84 and 86 cars on stock S brakes these days.

 

I have big black GTS brakes on my '79.

Front adapters from Carl at 928MS, paired with 322mm Girodisc 993TT 2-piece slotted front rotors for the proper rotor diameter and hat offset, then the rear S4/GT/GTS brakes in the rear with Powerslot 1-piece rotors and Hawk HPS pads and coated, braided SS lines.

Wheels are 18"

Stock brakes are adequate until they're not, like when you're running 75 mph up a country road on your way to SITM and the guy coming the other way on the 2 lane road decides he has enough room to pass the car in front of him, but doesn't.

 

maybe I just need pads then I notice they now squeal when going in reverse... I bought the car a few months ago, I doubt the last owner put new pads on for me

 

I am not sure that squealing in reverse is significant, but good pads are important. If you can't lock up the brakes (or give the ABS a workout) with a max-effort stop then you need new pads. There are many choices, a search here for "brake pads" will rival "what oil should I use". Some pads only work well after being warmed up, others work well when cold but overheat on mountain roads. Factory pads (Textar) cover both of those bases but are costly and dusty. After exploring both ends of that spectrum we're back to factory pads and a wash-bucket.

 

If you truly feel u need more stopping power focus on rotor diameter.

 

...assuming you've already put on some very good tires. Brakes don't slow down the car, they slow down the wheels.

 

I cursed the squealing of my Hawk plus pads for years until I fitted new dampers and then they never squealed again!

The Textar pads are indeed very dusty - I suspect all "good pads" will be.

 

For a driver, I'd start with some EBC "red stuff" pads and stainless steel brake lines front and rear. That "should" suffice unless you track the car or need to make repeated high speed stops.

I've bought various adapter brackets for performance cars over the years and they always left me wondering if the feel could be better. That could be just me but S4 brakes with stainless lines and good pads feels great and very direct.

I really have to stress the importance of pad selection. They can dramatically alter brake feel and grip. For example, I recently upgraded an OT track car from EBC red stuff to yellow stuff. Feel was noticeably diminished but the pads did take repeated high speed stops.
In my youth I did take a pad selctions advice from the parts counter guy for a BMW E32... he swore they were OE pads...nonsence... the brakes felts like mush and I had to take the long drive to the BMW dealer and get the right pads. Bought pads twice...feel was restored though.

FYI. Upgraded early 85/86.0 using to a complete S4 front and rear is the way to go but requires lots of other part changes becasue there are lots of differences including, sway bar links, backing plates and ABS computer and some wiring changes.

 

Proper functioning "S" brakes will lock up the wheels quite nicely. Once (actually more, but that's not my point).

Bigger brakes (S4 or GTS) show their worth with repeated heavy braking. The bigger rotors are able to absorb & dissipate more heat.

if you aren't in a situation where you need to stomp on the brakes over and over, the S brakes should do you just fine, presuming they are working correctly.

 

Wisconsin Joe hit on a key point...working correctly. 928 S brakes are excellent when everything is in good working order. DWAYNE has an excellent write up on how to rebuild the calipers, which is relatively easy to do. Brake hoses are a good idea. Master cylinder is a must if you don't know when the last time it was changed. Good pads and rotors, and have a nice day.
Hacker already spoke of this, I just wanted to reinforce it.

$ky is the limit for better brakes, but what you have can be excellent.
My take, overhaul what you've got, won't cost that much coin(in terms of a 928). Then decide if you want better.