Hey guys saw a recent thread by a new member asking about doing the rear brake upgrade to a larger caliper size thus allowing the 12" rotor on the back. This has always been a plan of mine to do with my full brake change the research I've done it looks to just be and early generation gp bracket and caliper you use for the mod, there are also kits on zzp/wbodystore.

My question though is a member brought up in that thread doing this size upgrade would screw with your master Cylinder, brake pressure and cause some haywire with your overall braking.

Now while I haven't been able to find any info that proves what he said but it does kinda make sense larger rotors would affect it, mainly has anyone actually done this mod yet or what do you think on it affecting the cars braking for the worse?

 

Great questions, I will be following this thread to as I want to upgrade my rear calipers.

 

Bottom line, you are increasing the size of the caliper and the fluid it takes to move the piston. I've never done a caliper upgrade (but for quite some time, I considered it). I have done a LOT of reading about people who did front F-Body caliper swaps. The common item mentioned was the brake pedal had to travel more to the floor before it would grab (and when it would grab it REALLY grabbed). I was NOT a fan of increasing pedal travel to get supposed brake improvement when just a better combo calipers and rotors would do the trick.

I have read about 1 or 2 wbody owners who did not like having big F-Body calipers on the front and tiny Wbody calipers on the back. Supposedly you can use '99+ Grand Am calipers on the rear of a wbody car. I did not research that idea much.

Hopefully people who did the F-Body swap well chime in (obviously they have 1st hand knowledge of it). My info is just reading on the subject. But in my opinion, if you are doing it for looks, leave'em (paint them, but don't swap them). If you are doing it for performance, research if you need it vs getting better rotors and pads.

 

Thanks a lot maniac, yeah that's around the assumption I've been under too it does make sense increasing the size would affect the travel speed and pressure, generally how much fluid is sent does add up it would change.

I am doing this for a performance upgrade so I will definitely be researching up my best options if going better rotors and pads or doing the caliper upgrade is the better route.
I personally am still pretty inclined to do the fbody and rear brake upgrade so maybe if I do I'll be able to give a full review first hand experience on it.

I wonder if you can upgrade the master Cylinder as well to counter the problem fix all issues?

Anyways I contacted zzp and wbodystore techs to get a little input here is what they had to say. I am also asking a few mechanic buddies in the area to get some more info.

Wbodystore gave pretty good answer- "On certain setups it would. *Whenever you change the volume of the caliper without also changing the master cylinder you're going to affect pedal position and pressure. *That said, there are literally thousands of big brake kits on the market for all variety of cars that don't touch the master cylinder. *In addition to that all of our kits are tested on W bodies and have sufficient pedal feel and vastly improve braking on the platform. *I'm confident if you talked to people that actually had the upgrades they would be singing their praises. *I promise you you'll love it, especially if you're someone that tends to be an aggressive braker."

And zzp- "There are no issues with pedal or proportioning with any of our products.

The monte has 12” brakes already so the advantage would just be getting twin piston alum calipers"

I'll keep you guys updated on my decision soon

 

I wish I had a car near me that had the F-body caliper swap to test first hand. If so, I may have seen this issue differently. But, I did not and given what the costs were for me to do all I wanted (upgrade the calipers new pads, rotors, powder coating the calipers), I could not justify the costs when i felt the risk was too high that I might not be happy.

But I AM happy with what I ended with (Bendix ceramic performance pads and AC Delco Advantage rotors all the way around, Goodridge braided stainless flex lines, stopping power is AWESOME)!

 

I have fbody front calipers & the pedal travel isnt much different than the factory ones

 

I believe I'm the one that chimed in about possible pressure issues with the rear brake upgrade and possible need to upgrade the master cylinder.
I did the front F-body upgrade YEARS ago with no regrets. Look at the size of the F-body brake pads compared to the W-body and to me it was a no brainer. I DO feel the pedal is a little firmer and the travel longer, but the stopping power is definitely way more. I wouldn't go back. In fact, I have replaced the 1st set of calipers with replacements because of salt corrosion. I still have the factory calipers JIC.

I would consider the ZZP upgrade, but I don't really feel the need, as the front brakes do most of the work. To me, it's not necessary, and that to me is why I do or do not do upgrades. I can't justify the benefit of the upgrade.

But yet I have both front AND rear strut tower braces. And the rear is deeply hidden by my stereo. I had a STB on my '01 SS LE, but not on the Intimidator SS? Didn't make sense to me. For the few $$$, that was a no brainer.

Convince me the rear brake upgrade is a necessity, and I'll probably do it. Not for the bling, but for better brakes.

 

I have fbody front calipers & the pedal travel feels the same to me..
The stock monte pad is on top , The bottom one is camaro pad..
Iam going to leave my rear calipers stock ..

 

It would be a nice time for you to put this issue to bed then Wayne. You can be our tester? Make and chart some Monte OEM rear and F body fronts hard stops. Then with your new upgraded rear calipers and F body fronts make and chart some new hard stops, and inform the Monte world of your findings.... LOL, would be some good to know info.......

 

THANKS for the pic Jerry. Now you can see why we like the upgrade in front.
And no thanks to the rear upgrade.