12" Rear Disc Brake Mod

..Its not that stupid a question.  I been thinkin about adapting the Firebird calipers to the rear.It is doable,ya just have to figure out how to adapt a caliper bracket for the rear and instal a spot caliper for the E-brake.

matt270avian wrote:

Has anyone done this? Can you put a set of front ones on the back, or at least put some on that don't have a completely retarded design? Forgive me if this is a stupid question, I'm not very familiar with brakes.

Not a stupid question, but I'd like to know why you think our rear brakes have a retarded design. I've replaced the brakes on mine many times over the years - except for the case of the OEM rear discs, the front brakes always wear faster than the rears. We have more than enough pad and rotor in the rear to do the job. My rear calipers are still original, even the grease in the slider pins, at 263k miles.

Ditto. All original rear hardware at 203k miles. I used to want more stopping power from the rear but with the hp+ pads back there i almost need better tires before doing any more upgrades now. In a panic stop the rear tires will lock up and the tail end can get a very uncontrollable in a corner. And that is with new 245 summer sport tires too.

Forgot to mention this, Matthew, but I recently wore my HP+ pads down after a couple years of good use. I was in a bind so replaced with cheap Duralast from AutoZone, planning to change them back eventually. I still have the EBC bluestuff up front.

Honestly, I don't mind the softer biting Duralast in rear, for the reason you mentioned. I have almost as much deceleration in a straight line now, and in the corners I worry less, especially in the wet. Plus the Duralast are quieter than HP+ and don't seem to be wearing the rotors as much.

I think I may end up somewhere in the middle, switching to Hawk HP-S for the rear. I know I recommended the HP+ to you since you were looking for a very good deceleration rates, and hope they aren't "too much". For me they worked, but I have more weight over the rear axle than most. One way to look at it - don't brake in the corners and you'll be fine!

I love them. My only problem is the dust seems to stick to the wheels way more than the fronts(hp+ also). Not sure why but i have to clay bar them to get them clean now. Doesnt wipe or wash off like the fronts do. 
I rarely ever brake in a corner. I learned a long time ago that the tires will only take so much. Either braking, cornering or accelerating. I brake late due to the stopping power but let off entering the corner and im always on the gas at or before apex. Fwd ftw lol

I think it sticks because it's being applied in thinner coats over time (maybe?).

You might try getting the wheels nice and clean, then applying a coat of wax. Should help remove the dust next time. I think they make special protectant products for this, but I don't know the peoduct name.

Idk because it is caked on in a day or two. I think part of the problem is i didnt give them a good cleaning after wearing off the black oxide coating on the new ebc rotors. That stuff probably adhered to the wheels with heat. I normally use meguires chrome polish and ultimate wax on them...havent done it since its in the mid 90s here

Do you still have the box? I'd check to see if the sent you HP+ or something different!

Mine always stayed pretty clean in the back.

Yes both the box and the back of the pads say hawk hp+ and the correct part #. I can get a pick later tho. Maybe they werr a bad batch? They do stop really well.

Doubt they are bad. I'm stumped on this one.

matt270avian wrote:

Has anyone done this? Can you put a set of front ones on the back, or at least put some on that don't have a completely retarded design? Forgive me if this is a stupid question, I'm not very familiar with brakes.

You _can_ put a set of fronts on the back - I believe the bracket will bolt up and you need to use the front bracket, caliper, rotor and pads, but then you will lose having an e-brake. (edit - I'm not entirely positive about the bracket being a direct bolt-on)

In general there isn't much need to do this. The front brakes do 80% of the braking.

Why are you thinking you want to do this?

I would just like a little better stopping power. I didn't understand all of the dynamics about it before I posted though. I plan on doing Abaddon's GXP mod as long as he says it's all good to go.

Are you autocrossing? The only difference between the '96 and '98 I believe they switched to larger front rotors. When my stock brakes are in good working order I can panic stop faster than anything around me. Unless you are doing track days I see no justification for 'larger' brakes unless something isn't working right.

Seriously you guys, when I panic stop I throw everything loose in the car at the windshield. I do not see any need to upgrade for street driving.

I do agree with you, for a 2 ton car it stops remarkably well. But I'm never satisfied, if I can lose a pound here or gain some power here I'll do it. Same goes with braking, I just want more. I don't need it, but if it saves me one day it's money well spent. I can already thank my new brake job for saving me more than once. There's a lot of deer and idiots around here......

Putting bigger rear brakes on a Riv is like putting larger rear wheels on. You're doing it for looks. Bigger rear brakes adds unsprung weight, too. It will interfere with the brake bias, which can be dangerous. Every car maker in the world puts smaller brakes in rear - not to save money, but for safety sake. Too much rear brake can easily cause loss of control.

If you want to improve stopping, focus on the front brakes. But like deekster said, you won't stop more quickly upgrading the fronts - you'll stop more quickly repeatedly from higher speeds, and the brakes will last longer.

I'd argue that you can autocross a Riv with stock brakes just by swapping all the pads to a more aggressive compound. Pads make a much more noticeable difference than rotor size or calipers. In the end, you can only stop as fast as your tires let you. The limiting factor in any vehicle is grip, so if you really want to decelerate more quickly, wider tires with performance tread is your ticket.

Installing a larger and lighter 2 piston caliper is a bigger job than one might think.you also have to install a proportioning valve to maintain bias and an emergency  spot caliper. it could work. lose some weight and get a better feeling braking system.

Good point. For our Lemons racer we bought a proportioning valve and planned to fine-tune the system that way. Then we realized we could do the same thing by changing just the pads to a different compound. We tried two different pads on the front and nailed it on our 2nd try! The front and rear wheels lock up at exactly the same time on dry track, fronts lock just before the rears in wet.

Here's a good read for anyone wondering why I'm not a fan of bigger rear brakes on a Riv:

http://www.stoptech.com/technical-support/technical-white-papers/rear-brake-upgrades

oldsman105 wrote:

For those of you wanting to do a brake upgrade here is a minor one.


Bonneville GXP brake brakets part # 18026216 Order 2.
and GXP Rear rotors (11.7" compared to stock 11")
and Pads of your choosing.



The rear brakes are the same on a Riviera.

Anyone ever confirm/do this? My rear rotors and pads are about due, so if all it takes are new brackets I'm game. I found a guy who replaced them with STS (yes, more STS lovin') brackets to get the 11.7" rotors.

http://www.pontiacbonnevilleclub.com/forum/topic39170.html

Also, anyone who has access to a parts counter (*coughAbaddoncough*), can you compare a Grand Prix rear hub to one off a Rivi? 97-03(?) GP's had the e-brake in the hub where we have it in the caliper. If the rear hub bolts on we have access to more than just the above mentioned upgrade.

Upon further inspection, the caliper brackets will work and there are a decent bit of vehicles you can pull them from. I'll be the guinea pig since my rear brakes need done anyways, so I wouldn't advise anyone else to do this until then.

Where to get the bracket from (MEASURE FOR 11.7" ROTOR FIRST, MAKE SURE E-BRAKE IS ON THE CALIPER AND NOT IN THE HUB/BEARING)

03-05 Park Avenue Ultra
00-05 DeVille
98-04 SeVille SLS
98-03 SeVille STS

Be careful pushing braking limits with the increased rear bias. I would use a lower friction pad (cheaper metallic like Duralast) to offset the extra leverage increased rotor diameter. That way you'll see the benefits from a larger pad/rotor combo (mainly added life and some added decel from higher speeds), without lift-off oversteer braking into a gradual corner.

Don't forget, cars that have the same front setup as us (97+) have the upgraded rear setup. That and the new rotor isn't much larger (.7"). Since I'm already running 1" larger rotors in the front (96 used 10.x", 97+ used 11.x") and F-body calipers things should be good. I grabbed the brackets today off a 2000 DeVille and will get around to putting them on sometime this year or early next.

If I'm not mistaken, the Parking Brake assembly is attached to the backing plate on the GP's, not the Hub. The Hub actually has nothing to do with the PB itself. You'd have to install the backing plate and all the necessary hardware from the donor car in order for the PB to work, IF the brake cable has the same end on it.

Or, screw the parking brake.....

Abaddon wrote:

Or, screw the parking brake.....

Hmm..... 30* incline on the driveway...... Neighbors parked directly across the street..... Nahhhhhh...

Ha. My P-brake cable has been rusted solid for a couple years now. The last time I used it, the rear brakes stayed applied.

Your driveway is that steep??!!

Abaddon wrote:

Your driveway is that steep??!!

Yep. 2 of my cousins even have driveways that are nearly 45*.