Front Caliper Upgrade

[Guest F14CRAZY]

Ah, I'd have to re-google it, but this is what I found out a while back.

But first, another challenge would be the fact that Corvettes have something like a 5x120mm bolt pattern, not the 5x115 we do. However, look at the photos of an ebay auction, and there seems to be a lot of room between where the holes are and the center. I figure a machinist could drill our bolt pattern (which would be even with the Vette pattern, if that makes sense). There shouldn't be any loss of integrity in doing this, I don't think.

I'm not a know it all Richard, I just know a bunch of facts that need to be put together, but...

Link to a Regal GS thread

Those are C5 calipers with 12'' rotors (F-body, I assume). Vette front rotors are 12.6. I'm thinking that because the Vette rotors cover the 12'' rotors fine, there's no sense in messing around with the Vette rotors

[Guest F14CRAZY]

Well, if you still wished to use the 12.6 rotors, there are aftermarket brackets intended for F-body cars that let you use C5 calipers/rotors. I'm thinking it would work...

ebay auction for the brackets

I've seen 12.6'' and 12.8'' said for the C5 rotors, dunno which is right but I'm thinking it's 12.8

[Guest F14CRAZY]

Uh oh...

If you check out the F-body brackets I linked, F-bodies use 4 bolts in a square pattern to hold the hubs to the knuckles. Reattas use three.

In short, we can't use the F-body-to-C5 brackets, and so we can't use those 12.8'' rotors after all

[Barney Eaton]

Guys...it looks like there has been some real progress on this conversion.

I did a quick check of all the posts but didn't see a list of interchangable rotors. In my file I show the following 1997-2004 rotors being the same as the Aurora...

Olds Intrique, Bonneville, all front drive Cadillacs (except the CTS) Buick Lesabre, park ave, Lesabre, Impala, Monte carlo

(I suspect the Regal, and Gran Prix since they are same car as the Impala)

So stock or aftermarket rotors should be a snap to find.

[Barney Eaton]

I have one other question for F14, Richard, and anyone else working on this conversion.

Will the stock Reatta caliper attach to the later car bracket?

My thinking is the bracket is what moves the caliper out further to accept the use of the larger rotor. Is this true?

As stated earlier, the use of the larger diameter rotor by itself gives some % increase in stopping power by virtue of the mechanical advantage of its larger size (lever arm)

I don't know if any of the newer calipers (except the dual cylinder Z28) actually apply more pressure than the stock caliper.

If the above is true, a cheap upgrade would be the larger rotor, the newer bracket and keep the old caliper.

[Richard S]

Barney, if I have reason to pull the wheel, I'll look at that and see if it is the bracket or caliper that allows for the larger rotor. As far as simply upgrading the rotor, that might help, but ignores the value of the larger pads fitted to the Z-28 caliper. If braking power is function of friction surface, wouldn't it take both a larger rotor AND larger pads to effect an improvement? Since the calipers are pretty reasonable, I'm not sure why one would only want to settle for 1/2 the equation. I don't think that "squeezing" power is an issue at all. The amount of pressure applied by the piston is more a function of the hydrolic capacity designed into the master cylinder. Too much and you get lockup anyway. I assume that the advantage of twin pistons is that they apply more even pressure over the length of the pad. It allows the engineers to use larger [longer] pads. The advantage of finned cast aluminum calipers is that they transfer more heat away from pad than our cast iron.

[Guest Greg Ross]

I am inclined to think this is a "Go Big Or Stay Home" option. If you're looking for an improvement in braking response this is definitely the way to go. Beauty of the combination that Richard has proven is that it can be "UnDone" In other words all the purists who want to keep their Reatta original/ return it to stock configuration can simply bolt the stock parts back on. Swapping the original parts on I think they would then really appreciate the benifit of the upgrade.

Credit for coming up with the Aurora conversion, at least where I got the original inspiration and data from, was Scott Pearson/ The Auto Shop. He still sells a complete kit based on the Aurora components. Had a quick look just now and couldn't find his web site?

[CADCHRIS]

Hi Guys. "Good Threads Should Never Die"!

Over the past few years, I saved many of your "Brake Upgrade" threads and was overwhelmed and impressed with what everyone had accomplished here with the complex brake upgrades to your Reatta's .

To answer "Greg Ross's" question above from 2007, here is the link I also saved from Scott Pearson/ The Auto Shop's tutorial which hopefully helps a little of where all this "Craziness" of big brakes may have started: GM E Body 12" Front Brake Conversion Installation

Or here is the website. Just close the address and insert ".": www (dot) theautoshop (dot) net/12BrakeInstall (dot) htm

That is where I basically started with wishing to upgrade the front brakes on my 91' Cadillac Eldorado which is why I'm here asking for advice for my "Cadillac" so I hope I'm not way out of line for not being a "Reatta Guy"!

Anyway, I hope all the experts can lend me a hand and your thoughts are greatly appreciated.

The 1991 Cadillac Eldorado has 5x115mm rotors like your Reatta's use....right?

My first concern is that the upgraded 12" (11.92") rotors from the 2004 DeVille, 98' Aurora, and others use a 5x118mm bolt pattern. Will these fit on a 5x115mm bolt pattern like my Eldorado uses, along with your Reatta's, and like the original Scott Person upgrade above on the Olds Toronado Trofeo that also used the 5x115mm pattern?

Did I miss somewhere that everyone needs to re-drill the 5x118mm rotors to fit the 5x115mm pattern or is it close enough to fit the original pattern?

I'd also like your thoughts on taking this mod further like some of you guys have done with the Camaro/Firebird duel piston calipers, and rear large caliper upgrade I also read about that Daniel put together a few years ago.

By the way, does anyone have the current link to the rear upgrade or any other new info on "Ronnie's" site that was mentioned in post #22 here by Ronnie?

http://forums.aaca.org/f116/new-brake-upgrade-255932.html

Thanks to anyone and everyone, and I appreciate your thoughts because this is the only place that "Can Help" on this subject!

Hope everyone had a Happy and Safe 4th of July!

Kind Regards,

Chris

Edited July 5, 2013 by CADCHRIS (see edit history)

[D-a-n-i-e-l]

If u want to upgrade your brakes I suggest 2000 camaro fronts and 96 sts rear. They work well with the stock master cylinder and there is no modification needed to run them as long as u have 16" or bigger rims. You will need to get the cables fro the 96 caddy to do the swap but it is a dirrect bolt on.

If you have 15" rims then the grand am swap should work well. Although I cannot pesonnally speak for pedal feel or life using them.

[handmedownreatta]

D-a-n-i-e-l said:

If u want to upgrade your brakes I suggest 2000 camaro fronts and 96 sts rear. They work well with the stock master cylinder and there is no modification needed to run them as long as u have 16" or bigger rims. You will need to get the cables fro the 96 caddy to do the swap but it is a dirrect bolt on.

If you have 15" rims then the grand am swap should work well. Although I cannot pesonnally speak for pedal feel or life using them.

i did this.the holes in the camaro rotor come oversized and will fit the reatta.im running sts wheels so the bolt patterns the same.

Edited February 8, 2018 by handmedownreatta (see edit history)

[CADCHRIS]

Thanks guys! Yes I'd like to upgrade to this 16" Caddy wheels:

http://www.lawheel.com/newchrome/4507/w06.JPG

The original 15" Snowflake Wheel:

1991 Cadillac Eldorado | Flickr - Photo Sharing!

I guess I should somehow start to compare wheel specs. from the Eldo:Reatta:Trofeo: and the new wheel to see if I'm going to have a problem or buy a used 16" wheel like above and mock up everything.

I'm glad the whole 5x115mm and 5x118mm is not going to be a problem. I've checked out "The Rock" (Rockauto's site) to get an idea of what I'm looking at.

I can't remember from everyone's discussion on this forum when or what makes/years the special brake hose banjo bolt is used or if there is a hose mod needed for one of the upgrades single or 2 piston????????

Daniel; I'm curious, what years for the Grand AM and do you think it will fit the 15" wheels?

Scott Person from The Auto Shop link above said it could be a problem using the single piston caliper from the 2004 DeVille, 98' Aurora and others that use the 11.92 rotor on the same cars with the JL9 Code which "I think ??" he's selling in his kit.

By the way, I just wanted to mention this innovative company I found a few years ago since you guys are really into brakes! They might have applications for the upgrades you guys are doing but not for our original brakes: Pretty cool technology! Looks like some of these parts are private labeled for Raybestos by Nucap.

NuCap DRT: (Drag Reduction Technology) pad springs I don't see them for the 2 piston calipers but I think they have them for the single pistons like the DeVille, Aurora:

DRT

Nu-Lok ( Piston Cushion/heat isolator) probable not beneficial with Phenolic Pistons or if they even have an application for a 2 piston caliper :

NU-LOK | PISTON CUSHION

Brake Align Latteral Runout Correction Plates:

BRAKE ALIGN™ - LATERAL RUNOUT CORRECTION PLATES

They have other technologies also that are integrated into mainstream brake pad manufacturing. Not sure what brands or if the Hi-Performance Pad companies use their specialized "Backing Plates". There's a "2 Guys Garage" video that talked about it also......missed that episode.

NUCAP | Videos

They have lots of videos about their technologies. I think NAPA carries the DRT, Nu-Lok, and Brake Aligns.

Just a few "Centavos" for you guys!

Now I have to figure out what I'm go'in do. I hope something will fit my orig. 15" or flashy 16" wheel I'd like to get!

This should be your theme here:

"Drive hard...........and brake harder!"

Regards,

Chris

Edited July 6, 2013 by CADCHRIS (see edit history)

[handmedownreatta]

i did a write up on my installing the camaro brakes.for some reason this site won't let me post links.search 2000 camaro front brakes

[CADCHRIS]

Thanks "HandMeDownReatta". Very informative.

Another question for you guys. I've read a few times where it was always brought up if these brake conversion would fit your 15" wheels.

Is it a backspacing problem where the caliper hits the back of the wheel's face, or do the larger calipers or rotors hit the inner radius of the 15" wheels?

If it's a backspacing problem, why not use high quality "hub centric" wheel spacers which would also provide a wider track. I saw that Jon/63Viking did this on his rears, but was not "hub centric" and was a "lug centric" setup: http://forums.aaca.org/f116/new-brake-upgrade-255932.html

A quick search showed some very good vids on "The TUBE:

Eibach Wheel Spacers, but nothing really close in their product line to our lug pattern ect....:

Eibach Site:

Wheel Spacers | performance-suspension.eibach.com

"Lugmanusa.com" looks good:

This guy looks like he knows his stuff and made in the USA. Long but very informative video: "Mywheeladapters.com":

Regards.

Chris

Edited July 6, 2013 by CADCHRIS (see edit history)

[handmedownreatta]

i had already changed from the ugly reatta wheels anyway so i didn't check.

[D-a-n-i-e-l]

http://forums.aaca.org/f116/big-brakes-another-option-316640.html (grand am front) http://forums.aaca.org/f116/bolt-brake-rattle-solution-upgrade-304512.html (96 caddy rear) These two have no fitment issues and work with the factory 15" rims. The Camaro fronts need at least a 16" rim.

[CADCHRIS]

Thanks guys.

Daniel, I've seen that thread a while back and forgot about it so thanks for posting it again.

So there are basically 3 stages of upgrades for the front brakes......right?

#1. 2000 Grand Am 10.94 Rotors, Aluminum Single Piston Calipers. Use 15" Wheels.

#2. 2000 era Aurora/Devilles 11.92 Rotors, Cast Iron Single Piston Calipers. Use 16" Wheels.

The best:

#3. 2000 Camaro/Firebird 11.92 Rotors, 2 Piston Aluminum Calipers. Use 16" Wheels.

I still hope someone knows that if option #2 or #3 is used, can wheel back-spacers be used to clear the calipers/rotors if still wanting to use a 15" wheel?

By the way, I went looking for this old thread regarding the rear brake rattles on the 91 Eldorados. Hopefully it will help you guys with Reatta's....... Note post #8, #10, and #24 for some good solutions to stop the rear brake pad rattle.

91 Eldorado rear brake pads rattle

Here are some items that "MAYBE" could be made to work to stop the rear brake rattles on your Reatta's. Not sure if you would have to drill the brake pad or not but maybe someone could come up with a way to use these clips used on a C4 Vette with the same problem:

C4 Corvette Anti Rattle Clips

Carlson Quality Brake Parts #H5610

1988-96 Anti-Rattle Front Clip | Vette Brakes & Products

Maybe Carlson makes something specific to stop the rear brake rattle....

Carlson Quality Brake Parts Sites:

Carlson Quality Brake Parts - Putting it together in Brake Parts!

[ Quality Brake Hardware ]

C3 Corvette Pad Inserts that slide over the ends of the pads:

C3 C2 Corvette Brake Anti-Squeak Kit 1965-1982 - Mid America Motorworks

Edited July 7, 2013 by CADCHRIS (see edit history)

[D-a-n-i-e-l]

The 96 Cadillac rear upgrade can use the 15" wheels, and you do not have to modify or create parking brake brackets. They are the same size disk as the Aura, brake rattle goes away forever, and your parking brake becomes one pump.

[Guest Mc_Reatta]

I still hope someone knows that if option #2 or #3 is used, can wheel back-spacers be used to clear the calipers/rotors if still wanting to use a 15" wheel?

No, as you step up on your list, your gaining in diameter, not thickness. It's the inside diameter of the rim that precludes its use, not its offset.

[CADCHRIS]

Thanks Daniel, I'm glad to know the p/b will be 1 pump because I was wondering. The rear STS conversion is what I'll do.

Thanks also McReatta for answering my question.........I think I want to do one of the bigger conversions either the DeVille/Aurora or Camaro/Firebird because the Eldorado is a little heavier than your Reatta's and is really scary trying to stop it.

I wonder if I could get enough clearance by grinding down the top heat-sink fins on the Camaro/Firebird duel piston calipers and still use my 15" wheels:

Product Detail

If so, I wonder if NuLock

NU-LOK | PISTON CUSHION or any others make the titanium piston ring isloator shims which stops heat transfer into the caliper which I'd use if they are made for those 2 piston calipers like even these from "Hard Brakes":

Hard Brakes - Titanium Brake Backing Plates, Brake Shims, Brake Heat Shields

D749 Titanium Brake Heat Shield for Chevrolet Camaro, Pontiac Firebird [TS-T-D0749] : Hard Brakes - Titanium Brake Backing Plates, Brake Shims, Brake Heat Shields

I put a lot into my original brakes trying to improve them for daily driving. I upgraded to front/rear Powerstop or Centric's X-drilled/Slotted rotors, Axis Pads, new Delco Master Cylinder, fr/rr Wagner reman. calipers and new rear proportioning valve, and fr/rr stainless steel braided hoses including powerflush and bleed and still NO improvement in stopping!!!!!!!!!!!

I really wished I would've researched this back around 2006 when I did everything because I would've probably at least seen Scott Persons/The Autoshop's conversion info that he posted in 2006 on his site.

I just hope I could somehow use my 15" wheels with the bigger conversion. Not sure how that 16" DeVille wheel will look but that's the only wheel I like. I don't think I'd be happy with the Grand AM Conversion which was noted to be marginal over the o.e. design but Grand Am does at least use aluminum calipers for the front and has slightly 3/4" larger rotor.

Bigger is definitely better to get these cars to stop and I'm just driving around town and not even on the track.......so many idiots cutting in front of me down here in S. Florida, jamming on their brakes, and people walking out in front of me and I can't believe I haven't hit anyone or anything yet, so I drive it like I'm "Driv'in Miss Daisy" at 19mph with those puny 10.25" rotors !

This is the reason I tried to improve on what I had which still didn't do crap. I can't believe GM let these cars go with such inferior undersized brakes for even safety sake. Of course, it wasn't until 1997 the 11.92 rotors were available in DeVilles/Aurora's and then became intengrated into other models in the latter years. So much for the NTSB back then.

The original brakes just always feel glazed.

Not sure if you guys experienced that feeling with your Reatta's under heavy or emergency braking situations with the smaller rotors?????????

Thanks again for your advice,

Chris

Edited July 8, 2013 by CADCHRIS (see edit history)

[CADCHRIS]

I was even considering these different mods since I was so disgusted with my brakes I didn't know what to do a few years back. More cool technology in brake pad cooling....just posting for the h'll of it just in case some of you guys are really gett'in on that center pedal or racing your Reatta's:

STUFF WE LIKE: Fade Stop Brake Coolers | Safe BrakingSafe Braking

Four Products

Four Products - CoolShim Technology

Fade Stop Brake Cooler

Water Cooled Brakes on GTR's!

Willall Racing WR35WS Brake Cooling System for Nissan GT-R | Nissan GT-R News - GTRBlog.com

Idea: DIY heatsink brake pad shims: Grassroots Motorsports forum: Grassroots Motorsports Magazine

Patent Info on Brake Pad/Caliper Cooling:

Patent EP1929171A4 - Brake pad cooling apparatus and method - Google Patents

[Guest Mc_Reatta]

I too felt that the brakes on my old Le Sabre and the Reatta were a little undersized for the weight of the vehicle requiring a healthy push on the pedal to achieve maximum deceleration. (lock-up or ABS activation).

I decided to try the upgrade on my personal Reatta as I already had mounted 16" Caddy wheels and figured that when I needed to do brake any work on them I'd look at upgrading them instead of just replacing them.

Since most of the vehicle's weight is on the front wheels during a stop, it made sense to do the fronts first to get the most bang for the buck out of an upgrade.

Reviewing the good work done by the pioneers on this forum as to various options for calipers and rotors, I decide to go with the aluminum dual piston caliper for its performance, weight and corrosion resistance.

At first I thought the increase in stopping performance would be due to the increase in surface area the larger rotor and caliper would accommodate. But in researching the subject to refresh my memory about friction and dynamics, I learned that the increase is stopping power is virtually entirely due to the fact the braking force is applied at a greater distance away from the center of rotation. Same principle as using a longer breaker bar to break a nut loose. Other factors contribute to overall performance like heat transfer (fade potential) and piston area (pedal effort). Upgrading to larger rotors and calipers improves both of those as well.

The improvement in the stopping force from upgrading the fronts with the Camaro Z-28 brakes is quite dramatic. You will not longer get the impression you have to push the pedal thru the floorboard to achieve maximum deceleration. You get the impression you can stand the car on its nose if you push all the way. When I now drive one of the stock Reattas you realize how much further you have to push the pedal to achieve the same stopping power.

I don't drive under conditions that would tend to build up a lot of heat in the brakes, so I can't confirm the expected improvement in fade resistance from increased heat transfer. Maybe someone who has done an upgrade and drives in mountainous terrain can add a comment.

I do recall someone who had to grind some of the cooling fins down to prevent interference with his rims, but I don't remember if it was the particular 16" rim he had or he was trying to use a 15" rim.

I have the parts on hand to do the Caddy upgrade in to the rears, just haven't gotten the "round-to-it" yet. I tried to find an aluminum rear caliper but could not find any with the integral parking brake we need, so the Caddy rear was the best choice.

I think you will find the add on extras you post links too are not really necessary nor of significant benefit to a properly functioning caliper properly installed on the car.

[handmedownreatta]

OK. I just did some comparing.the reatta wheel is tapered at the back.my best estimate is it will take a 2.25 or 2.50 inch spacer for the wheel to turn.I have no idea if that would cause it to rub on turns.your caddy wheel may be different.I think my 15inch aftermarket wheels will clear the LSI front brakes I'm putting on my camaro.Chevy trucks from 73-87 had twelve inch brakes and 15 inch wheels.the good news for me is a 2.5 inch spacer will allow me to use my spare tire.BTW the fins are on the back of the caliper. They aren't the problem.

[CADCHRIS]

Thanks guys.....informative write-ups.

Mc_Reatta; I think I once heard something to the fact you mentioned about rotational force applied further away from the center of rotation now that I think about. Probably when I was researching how to improve my brakes way back. I wonder if we both read it on one of the "Big Brake" mfgs. sites like Willwood, Baer, Stainless Steel Brake Corp., Stoptech, Brembo....

Do you have any links that talks about the concept that you know of?

I wonder if that concept directly applies to drums? But of course drum system have their own issues which I'm also trying to decide what to do for my 91 Fleetwood Brougham since the guys on the Caddy/Impala Forums are converting the rears to Impala/Caprice discs and I'm still debating on using the product below that eliminates the vacuum booster and convert to a "Hydro-Booster" which will give me more clamping force without having to go with the front big brake kit and larger wheels.

Is this the front 2 piston caliper from the 2000 Camaro/Firebird you guys are using below?......the fins are on the top not sure if there will still be enough clearance though to use a 15" wheel. Hopefully someone might remember who ground their's down for more clearance and which wheel they used:

Product Detail

I was so disgusted back when I did all those upgrades to the original set up, I was wondering if maybe increasing the booster size would improve clamping force. I then stumbled onto a few full page ads by different company's for this device in the Street Rod and Trucking Magazines called a "HydroBoost" where you eliminate the booster and use power-steering hydraulic pressure to assist the brakes which far exceeds booster clamping force pressure.

Good Video: V8TV, Muscle Car Of The Week, V8 Speed & Resto Shop 314.783.8325 - Hydroboost Brake Booster Cures Bad Brakes

Hydratech Braking:

Welcome to Hydratech Braking Systems :: High Performance Hydraulic Brake Assist Systems

I know that I'll be happy with the upgrades everyone here figured out, but I was really looking down that path back then when I didn't know what to do. I'm sure the HydroBoost would do a lot, but would probably warp even x-drilled/slotted original sized 10.25 rotors. It would be interesting how much it would do since they sell a universal unit.

I wrote to them yesterday about my 91 Brougham and also asked them about my 91 Eldo. I'll let you know what they say.

"Handmedownreatta": So the backside/inner of the stock 15" Reatta wheel is larger in diameter?

If you ever take that wheel off, can you measure it. Do have the 2 piston calipers on your front yet?

Or can someone else measure a the inner back edge diameter of a Reatta wheel who might have it off the car?

Just for laughs, I want to be able to stop my Eldo so hard and fast, this happens!

See :33 sec mark:

Thanks,

Chris

Edited July 10, 2013 by CADCHRIS (see edit history)

[handmedownreatta]

i think the problem is the caliper sticks farther out than the front of the rotor.so the area of the wheel where the caliper is has to be recessed unless you run a spacer.the reatta wheel is tapered so where would i measure it?as i measure to the outer edge of the caliper[6.5"] the wheel needs to be 13 inches minimum on the inside to at least 3/8 inch past the mounting flange.

[CADCHRIS]

Thanks.........sounds more complicated than what I was imagining. I was hoping others who had tried it would really know where it was hitting and from what measurement, and how much of a spacer was needed to clear a 15" wheel without making the front end stance of the car look ghetto-goofy.

I'd also have to back-space the rear the same so the tracking is not off.

I guess I'd have to buy/borrow some calipers and brackets from the parts store bolt it up and see how much my 15" wheel needs back-spaced and still look o.k.

I wonder if the Caddy 15" wheel is different in certain dimensions than your Reatta 15's.

[Guest Mc_Reatta]

Stock Reatta rim has an inside diam of 12.5" at the hub tapering out to almost 14.5" at the inner edge.

I was looking at automotive engineering sites refreshing my memory of the applicable forces, coefficients and formulas governing breaks and stopping performance, not manufacturer's sites.

Think you will find those claims from HydroBoost etc. are misleading.

They will decrease the pedal force and travel required to achieve a desired clamping force, but will not improve the stopping distance of your vehicle unless your current brakes are not capable of supplying enough clamping force to lock up the wheels or initiate ABS cut in.

Yes, that is the dual piston Camaro caliper that is the upgrade of choice if you have space needed.

Yes, concept of distance between point of clamping force and rotational axis applies to drums also.

[handmedownreatta]

GM Brake Upgrade Option Measurements - Thirdgen F-body Brake Upgrade | Luke Skaff might be helpful.

[CADCHRIS]

Thanks McReatta, I'll have to measure my Eldorado Wheels. Now I know why 16's are needed. How about lay'in those Engineering sites on me! I like to read crap I don't understand. The HydroBoost claims more psi to the caliper which should be greater clamping force when even more pedal effort is used, right?

I'd still like to see their hard data before and after. Some of their demo vids testing looked authentic like here at 2:12 but I wonder what system they had when they say before / after:

Of course, It looks like it was with the stock system and the improvement was with a total big brake system and custom suspension ect. and huge a.ssss tires along with their HydroBoost......so hard to compare what the HydroBoost does by itself:

http://www.classicperform.com/ProjectNova/ProjectNova.htm

Handmedownreatta; Wow.............what a link and website. Thanks! That guys got his sh-t together. Very interesting projects including his GM HEI to DIS conversion. I have to pass it around to see if we can do the same for our Cadillac 4.9' HEI's.

What that guy was doing in brake mods in the link you posted reminds me of what I saw on the Impala sites brake upgrades for the Imapal's, Carpice, and my Brougham. A guy over there also offers a piece mill version using some parts and hubs from the company KORE3 but uses DBA rotors that are only thicker and not larger in order to keep 15" wheels, but I think the concept is not beneficial unlike going to larger diameter rotors all together like KORE3 offers: KORE3 Industries LLC: On and Off-Road Performance Automotive Components

I'd post the Impala link if you want, but its so confusing and doesn't apply here.

Edited July 11, 2013 by CADCHRIS (see edit history)

[Guest Mc_Reatta]

Think this is one of the sites:

http://deepblue.lib.umich.edu/bitstream/handle/2027.42/1354/13894?sequence=2

Yes, they did more than add psi to get their claimed results.

We have plenty of psi with our Teves systems, so we don't have any issues there.

I'll bet that there is enough in a proper Eldo vacuum booster to achieve the clamping force for max deceleration, though pedal force may be high.

Increasing the piston's area in the caliper by upgrading to a larger single or dual piston one will do wonders to reduce the pedal force needed to reach that same clamping force. and increasing the diameter of the rotor and moving the pads outboard will decrease the needed clamping force which will further reduce the needed pedal force.

Get some bigger rims and go for it. The life and property you save may be your own.

[CADCHRIS]

Thanks for the link.

Like I mentioned, on both my 91 Eldo, and Brougham had all upgraded factory components, even if I stand on the brakes in an emergency low speed stop around 35mph, they won't bite and feel glazed. They both DO NOT have a high hard pedal under normal braking like a bad booster.

One anomaly that really bothers me is when jamming on the brakes, the pedal does not go down quickly and is slightly hard. This only happens when quickly applying the brakes and it is momentarily hard and feels like I'm trying to push the pedal through sand. I even hear a woosh sound on both cars that I presume is coming from the booster action.

The booster is the only part I have not replaced on both cars but its been doing this for years. It holds vacuum and passes other tests so maybe there is something going on inside. I even thought about increasing booster ratio.

I think I really noticed it when renting a few newer cars and how touchy and powerful the brakes are with newer technology. Still kind of p.m.o. that these brakes never felt right. Well...........I know where I've been, and I know where I'm going! Bigger Brakes! I still have to figure out what to do on the Fleetwood and is limited to doing discs in the rear, and upgrading to better friction in the fronts.......

[Guest Mc_Reatta]

First thing that comes to mind from your description of the pedal feel is the flex brake lines. If they're OK. then I'd suspect seals internal to the master cylinder. I don't think the booster is your problem.

[CADCHRIS]

Like I mentioned in post #99 for my Eldorado:

"I put a lot into my original brakes trying to improve them for daily driving. I upgraded to front/rear Powerstop or Centric's X-drilled/Slotted rotors, Axis Pads, new Delco Master Cylinder, fr/rr Wagner reman. calipers and new rear proportioning valve, and fr/rr stainless steel braided hoses including powerflush and bleed and still NO improvement in stopping!!!!!!!!!!! :("

On my 91 Fleetwood Brougham: NEW: stainless steel braided hoses, Wagner calipers, Axis pads, Delco Master Cylinder, , x-drilled Raybestos front rotors and new Raybestos shoes, Wagner wheel cylinders with hardware and pressure flushed. I did not put a front proportioning valve on the Fleetwood that goes under the Master Cylinder. I still may buy a Phoenix Reverse Pressure Bleeder since the concept seems logical.

Something tells me its inherent to the design of the Brake Booster on both of my 91's. I wish I could find the same models to drive and compare them too.

This is why I was reach'in for the stars on all the crazy brake mods......

Edited July 11, 2013 by CADCHRIS (see edit history)

[wws944]

With all the high tech stuff you are looking at, I have to ask what pads are you using?

Good pads are designed for specific temperature ranges. A pad designed for racing, or towing heavy, is often poor for normal street use and vice versa. Higher performance pads need to warm up - meaning the first stop or two of the day you'll wonder where your brakes are. But when hot, they grab like crazy. Cheap 'lifetime warranty' pads probably don't work well in any temperature range.

I've usually had good luck with the semi-metallic Delco Durastop (not to be confused with aftermarket Duralast) pads - if one doesn't mind pink brake dust. On my 944, I had Porterfield street pads in it for a long time and really liked them. Expensive though.

[CADCHRIS]

Thanks "wws944". Yeah, I've heard about specific temp ranges in pad selection. I have AXXIS Metal Masters on both Cadillacs. I'll have to find my old boxes because I think one was Axxis Ultimate's and the dealer I bought all my stuff through can't determine what I bought due to an error when they entered all my parts on the invoice.

Someone recently told me about Porterfield Pads who make them for HAWK. I just did a search on AXXIS pads and found these debates of Axxis vs. Hawk.......interesting reads.

Hawk HPS vs. AXXIS metalmaster - DSM Forums

How does Axxis Metal Master and Hawk HPS compare? - BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X)

Axxis Metal Master vs Hawks pads - RX7Club.com

Maybe I should just go back to Delco Pads.

Now I've really got a headache after some other stuff I read from a well known SAE Brake Engineer........I hate to post it, because it just might get me banned here! :eek:

But, I need you guys to look at it even though I'm still going to upgrade to the bigger brakes like everyone else did here.......I'll post it up soon.

Regards,

Chris

[Machiner 55]

Chris,

Now I've really got a headache after some other stuff I read from a well known SAE Brake Engineer........I hate to post it, because it just might get me banned here! :eek:

Please, do tell.

John F.

[CADCHRIS]

Memory Relapse......I just remembered "WHO" mentioned Porterfield Pads to me last week.....It was the Raybestos Tech Line Guy who said that's what he uses on one of his vintage hot-rods.....pretty funny.

Anyway, here's how I got linked to the "SAE Brake Engineers" pg.

I got a very long detailed e-mail back from HydroBoost and he basically said : " I do know that this will dramatically increase your overall braking in both vehicles, to the point of not having to pursue any further upgrades at the wheels!

But now I'm still concerned with what I read and do not fully understanding on the "Brake Engineers" pg. below.

Hydroboost indicated that my 91' Fleetwood Brougham utilized something called a "3 Piston Quick Take Up Master Cylinder with a exaggerated rear register size......" I said to myself: "A What?":confused:................So I had to do a search on that kind of MC I had.

So here's where I started, but just go to the other 3 links below.

Note the link in post #11 no longer worked and I used "Waybackmachine" that revives dead links:

braking force, quick-take-up, - Automotive Forums .com Car Chat

And here is where I ended up:

James Walker, Jr. (SCR Motorsports) is a licensed and registered Professional Engineer specializing in chassis, brake, and electronic brake control systems

http://www.teamscr.com/about-james-walker-jr/about-james-walker-jr.html

See this article under "THE CALIPER".

http://www.teamscr.com/motorsports/tech-articles/34-braking-systemsin-plain-english.html?showall=1

He cautions about using larger piston or multi-pistons with more fluid to piston area which does not match the rest of the systems original design. BUT, he does not state anything about using larger rotors when upgrading to a larger caliper, so maybe it balances the end result....... I don't know what to make of all this now. Could the upgrades that have been put together here going from the 10.25 to 11.92 rotors and single or 2 piston calipers be just "Dumb Luck" and it works just because it does??????!

A long time ago, I think I once read somewhere that the caliper must match the master cylinder or something to that effect.......

Here's his book: "High Performance Brake Systems" by S/A Books:

http://www.teamscr.com/the-book/about-the-book.html

Sample pages from his book:

http://www.teamscr.com/the-book/sample-pages-pdf.html

Here is the main Tech Page:

http://www.teamscr.com/motorsports/tech-articles.html

Has anyone here who has gone "Bigger" ever performed a before and after 60-0 brake test maybe using a G-Tech, Vericom, or Smart App to measure stopping distance?

I'll have to read the NTSB link that Mc_Reatta posted above...... Mc_Reatta, I'm sure you've seen info somewhere in that paper that contradicts what this engineer is saying.....

Edited July 12, 2013 by CADCHRIS (see edit history)

[CADCHRIS]

With consideration of what that Brake Engineer states, I did a quick look up of the different calipers pistons and calculated the area of the pistons:

Instead of calculating the area in square inches, I calculate the area in milimeters.

Original 10.25" Rotor:

91 Eldorado/Reatta Caliper: CENTRIC 14262088 - single piston 63.5mm piston bore =

3166.92 mm piston face area

2003 Aurora / 2004 Deville 11.92" Rotor;

Caliper: CENTRIC 14162146 - single piston bore 63.5mm piston bore =

3166.92 mm piston face area

2000 Camaro 11.92" Rotor;

Caliper: 2 Piston CENTRIC 14162126 - (2) 45mm pistons/bores = 1590.53 piston face area x 2 pistons =

3181.06 mm total piston face area.

I used this simple calculater below:

CalculateMe.com - Calculate the Area of a Circle

So I guess I kind of jumped the gun.....sorry. Looks like the piston areas are very close between all 3 calipers so it should not affect the master cylinder like the Engineer states when going to larger calipers. I just wonder what the total extended piston area would be to lamp the rotors for all three calipers.......:confused:

I won't even go there!

I'll compare the Rear STS conversion as compared to the original calipers and edit this.........

Let me know if I'm not making any sense and doing these calculations correctly, but I was just trying to rationalize this Engineeringly!

1991 Eldorado/Reatta Rear Caliper - CENTRIC 14262521 = 38 mm piston bore

1996 STS Seville Rear Caliper - CENTRIC 14162548 = 38mm piston bore

Looks like everything is the same hydraulically in (fluid displacement), except for the increase in Rotor Sizes and Larger Pad contact areas.............don't know if that could somehow be negative.

It would also be interesting to somehow compare all 3 cars master cylinders hydraulic displacements as there could be some benefit there if they could be converted. Just a random thought......

I'd still be interested in knowing stopping distances and pedal feel from those who have performed this big brake upgrade.

Edited July 12, 2013 by CADCHRIS (see edit history)

[handmedownreatta]

the way i look at it is the camaro was the fastest gm car from 1998-2002.except maybe the corvette.it stands to reason that gm would have made sure the brakes were capeable of stopping it at high speeds.

[Guest Mc_Reatta]

You're getting way too wrapped around the axle in your pursuit of brake design. (pun intended )

Looking at the forum link you provided, there are many posters who showed their lack of knowledge of hydraulics and fluid mechanics. There were only a couple of posters that offered factual information.

As to the racing driver engineer, he knows exactly what is involved, but he oversimplifies some things and exaggerates the significance of other things to grab your attention and make his writings and courses appeal to more people (mostly race car drivers trying to upgrade their brakes apparently).

The biggest gem he mentions is the fact that no matter what changes you make to your braking system, there will be no change to the stopping distance of your vehicle.

The only way to do that is to change the tires, the road surface, decrease the weight of the vehicle, or drive slower to start with.

So anyone who clams braking system changes will decrease the stopping distance is blowing smoke. What does change is pedal travel and force needed to achieve a given clamping force, and better heat transfer from larger rotor and caliper surface areas.

He calls the pedal action, "driver tuning". That is what gives the impression of better brake performance as you reach greater deceleration rates with less push on the pedal. The feedback that you can unleash that stopping power quicker and easier gives one more confidence in bringing the car to a stop than the sock system offers.

He goes overboard in stating the effects of "compliance" brought about by increasing the size if the calipers along with fluid requirements and increased unsprung weight. The changes brought about by going with the Aurora or Camaro caliper are not that significant to overwhelm the master cylinder, and he obviously never held a dual piston aluminum Z-28 caliper in one hand and a stock steel one piston in the other.

The reference to a "quick take up" master cylinder refers to the ability to move more fluid quicker to push the piston and pad against the rotor so that braking can begin.

So pick your poison as upgrading rotors and calipers or installing hydroboost or both will adjust the driver tuning in the direction you say you want it to go.

Edited July 12, 2013 by Mc_Reatta (see edit history)

[wws944]

Thanks "wws944". Yeah, I've heard about specific temp ranges in pad selection. I have AXXIS Metal Masters on both Cadillacs. I'll have to find my old boxes because I think one was Axxis Ultimate's and the dealer I bought all my stuff through can't determine what I bought due to an error when they entered all my parts on the invoice.

I have not used Metal Masters, but you do have to watch out with metallic pads in general. They may operate in a higher heat range than normal street driving would provide.

Someone recently told me about Porterfield Pads who make them for HAWK. I just did a search on AXXIS pads and found these debates of Axxis vs. Hawk.......interesting reads...

I used the Porterfield R4S pads. (Not sure what is in it now. Something my mechanic liked a few years back.)

Note that the Durastop pads are different than stock GM pads.

Can you lock up your brakes now? If so, all the bigger rotors and calipers are going to buy you is fade resistance when they are really hot. (Think towing a big trailer down a mountain side, or repeatedly doing high speed braking at a race track.) If not, it is possible that you have other problems. For example the 20+ year old hoses might be swelling and/or partially blocked and so are ready for replacement. What sort of 60->0 times can you get, compared with road tests of new cars back in the day?