Are the Dual Piston Rear Calipers noticeably better?

[5StarCustmSolutns]

Just wanted to ask as Ive been on 4 sets of scales in the last few weeks and am averaging 3400 front axle and 3480 rear axle...
We had another 24hrs of Appalachia Off-Road Rally last weekend; and I had a several mile stretch (again) at the end of a long long downhill traverse with 16-18? very low speed corners, in which I had to resort to a slow cruising pace because of the overheating of my brake system.. Im inclined to think it's a little bit fluid related, a little bit rotor related, a little bit pad related, and a little bit caliper (design?) related...

Front: currently running 6-7yr old Power Stop Z36 calipers(OE core returns that get cleaned and painted). I replaced the seals, pistons, pads(Z36) and turned rotors 16 months ago

Rear: OE calipers, bought new 16 months ago, with Power Stop Z36 pads and rotors
-R rear is currently sticking, AGAIN. For the third time in last 5yrs, and on 2nd caliper.

Fluid was also flushed 16 months ago..

[ To avoid another long explanation of a lessen learned the hardest way, here are the cliff notes: Replaced rear calipers as pair after breaking off stuck bleeder bolt in Z36 caliper.....it's what I do....special talent I was born with....many years ago earned nickname BoltBreaker 5000 lol. I'm sure most who read this will naturally think: A guy who earns that nickname is very good at drilling and tapping......no that does not apply here either.....or at least it didn't as of 16mos ago.....or maybe better said patience when drilling and tapping did not yet apply here 16mos ago!
Now have drill press, proper vice, cutting oil, decent drill bits, and may be ready to get over the hump ]

Could the dual piston rear help? or am I going to have to go deeper, with a more expensive upgrade?

 

[Geotrash]

Just wanted to ask as Ive been on 4 sets of scales in the last few weeks and am averaging 3400 front axle and 3480 rear axle...
We had another 24hrs of Appalachia Off-Road Rally last weekend; and I had a several mile stretch (again) at the end of a long long downhill traverse with 16-18? very low speed corners, in which I had to resort to a slow cruising pace because of the overheating of my brake system.. Im inclined to think it's a little bit fluid related, a little bit rotor related, a little bit pad related, and a little bit caliper (design?) related...

Front: currently running 6-7yr old Power Stop Z36 calipers(OE core returns that get cleaned and painted). I replaced the seals, pistons, pads(Z36) and turned rotors 16 months ago

Rear: OE calipers, bought new 16 months ago, with Power Stop Z36 pads and rotors
-R rear is currently sticking, AGAIN. For the third time in last 5yrs, and on 2nd caliper.

Fluid was also flushed 16 months ago..

[ To avoid another long explanation of a lessen learned the hardest way, here are the cliff notes: Replaced rear calipers as pair after breaking off stuck bleeder bolt in Z36 caliper.....it's what I do....special talent I was born with....many years ago earned nickname BoltBreaker 5000 lol. I'm sure most who read this will naturally think: A guy who earns that nickname is very good at drilling and tapping......no that does not apply here either.....or at least it didn't as of 16mos ago.....or maybe better said patience when drilling and tapping did not yet apply here 16mos ago!
Now have drill press, proper vice, cutting oil, decent drill bits, and may be ready to get over the hump ]

Could the dual piston rear help? or am I going to have to go deeper, with a more expensive upgrade?

I know those winding West Virginia roads you're thinking of. Pulled our 7500 lb camper up to Cass from Richmond back in 2021, plus several camping trips to Gauley Bridge over the years. Never had a problem with the brakes though - I use engine braking aggressively and will pull over whenever I can to let anyone trapped behind me get by.

 

[5StarCustmSolutns]

I know those winding West Virginia roads you're thinking of. Pulled our 7500 lb camper up to Cass from Richmond back in 2021, plus several camping trips to Gauley Bridge over the years. Never had a problem with the brakes though - I use engine braking aggressively and will pull over whenever I can to let anyone trapped behind me get by.

This exact downhill Im talking about ended at the Cass VFD lol.. Problem was I began putting heat into the brakes on the other side of, and at the bottom of SnowShoe Mountain. That stretch of Rt.66 may well be the most elevation change up and back down over one mountain, of any paved road this side of Boulder? Because of brakes I got the checkpoint set up with a little over 8min to spare...

I also engine braked my way into a lot of those corners, and smoothly pumped the pedal hoping to let some hot gas escape on on the release strokes. I eb'd so hard my Borla Touring was gurgling like an S-Type or an Atak lol... But it was definitely not the proper controlled descent you are describing...
Maybe my question shouldve been what is the best bang for buck brake upgrade?

 

[petethepug]

Upgrading the brakes up front will help. The rears are already larger than the front. The front are under-braked.

If not done already install braided steel brake lines and upgrade the front to the PPV / Brembo 6 piston calipers and 16” rotors. The ABS will recognize the larger brakes and properly modulate to better balance your system.

 

[5StarCustmSolutns]

Upgrading the brakes up front will help. The rears are already larger than the front. The front are under-braked.

If not done already install braided steel brake lines and upgrade the front to the PPV / Brembo 6 piston calipers and 16” rotors. The ABS will recognize the larger brakes and properly modulate to better balance your system.

Thanks Pete, as this most definitely qualifies as bang for the buck! But I just went from a 20" +18, to a 17" +18 wheel for better Off-Road performance :-/
I will most definitely make certain there's no way to pull this off? But at a glance, it doesn't look do-able?
It's never easy to have your cake and eat it too lol

If this is not an option, is there another bolt on solution out there that you know of?

[I promise Im not being lazy, there are a few subjects on here that now have so much info that it becomes a matter of having the time to read through all the posts to be able to get the pertinent facts (which is not a bad thing, except for the amount of time it takes). Right now in my life Ive only got a few minutes a day free to do things like this and Im doing my best to spread them around the activities Im involved in lol]

And if that solution is ordering 4 or 6 piston calipers and fabricating my own brackets?? Then thats what it is.... My goal here, as with all my modifications, is to increase the performance, but do so on a moderate budget. Similar to the long travel control arms, I don't believe in paying someone for something I can do myself....

 

[petethepug]

Well that’s not what I expected. 20” min for the front brakes. Here’s the rims the Popo use for those.

STLTAHPD Chevrolet Tahoe Police Wheel/Rim Steel Black #84947815

I wonder if the four pot brembo will fit under the rear 18”?

 

[Marky Dissod]

I wonder if the four pot brembo will fit under the rear 18”?

4piston front brake kit fits under 18" wheels.
6piston front brake kit needs 20" wheels.

 

[petethepug]

At least you’ve got the option with the 18’s to add C7 non-Z51 Calipers (Part Numbers) with adapters. You’d also still be able to install x drilled & slotted OE rotors with the C7 kit.

 

[_Barry_]

Why do you think a "dual piston" rear caliper is going to help an overheated brake system?

And how do you know it's "Overheated"? Are you experiencing brake fade, soft pedal, what exactly?

75-80% of braking is at the front wheels in a normal stop. If the rear is overheating then a stuck caliper is the likely culprit. That will overheat quickly and you mention the rear sticking... When brakes are lightly loaded the front/rear % may be different. Is it the rear overheating? Front? Both?

The amount of heat generated is the same regardless of what brake rotors/pads/caliper you have. You will need to not generate additional heat with any dragging pads (sticking) and then get rid of the excess. Brake fluid - if your pedal is going soft due to fluid boiling, change it and make sure you use a high quality fluid. Larger rotors will dissipate heat better - more surface area. Then there are cooling ducts and fans.

Your brake system was not designed to operate in a continuous fashion, braking a 7000 pound load, which is probably the biggest problem.

 

[petethepug]

Oh yea, if your calipers are sticking replace the brake lines with stainless braided as previously mentioned. Just before they burst they collapse on themselves and hold enough pressure to allow the pads to drag.

 

[tinkersmithinc]

At least you’ve got the option with the 18’s to add C7 non-Z51 Calipers (Part Numbers) with adapters. You’d also still be able to install x drilled & slotted OE rotors with the C7 kit.

View attachment 453278

I saw those, and I know there's a small company who sells conversion kits, but I guess what you're saying is that we can fabricate, retrofit it ourselves?

And how would that work differently for the front and rear? Apologies if I missed an explanation of this somewhere else!

 

[tinkersmithinc]

Correcting myself: I just realized they have 2 products, one bracket for the proper 6 piston caliper upgrade for the front (minimum 20" wheels), and the other bracket for the 4 piston upgrade for the rear (minimum 18" wheels). And exclusively for a limited set of donor corvette and cadillac calipers. Obviously this would save money if you didn't wanna buy thousands worth calipers and have a donor at home. I don't know how I feel about diy fabrication of those, unless you're a decent machinist with a decent mill?

Just to avoid confusing anybody else reading these forums, these brackets are exclusively for using those particular Corvette and Cadillac donor calipers, and have nothing to do with any ot hg er rotor+caliper set you may buy for aftermarket brake upgrade (from $400ish amazon sets to $3k wilwood sets): those sets would be simple bolt on parts (apart from exceptional minor grinding for some wheels), so far as you get the right rotors and pads.

 

[tinkersmithinc]

Thanks Pete, as this most definitely qualifies as bang for the buck! But I just went from a 20" +18, to a 17" +18 wheel for better Off-Road performance :-/
I will most definitely make certain there's no way to pull this off? But at a glance, it doesn't look do-able?
It's never easy to have your cake and eat it too lol

If this is not an option, is there another bolt on solution out there that you know of?

[I promise Im not being lazy, there are a few subjects on here that now have so much info that it becomes a matter of having the time to read through all the posts to be able to get the pertinent facts (which is not a bad thing, except for the amount of time it takes). Right now in my life Ive only got a few minutes a day free to do things like this and Im doing my best to spread them around the activities Im involved in lol]

And if that solution is ordering 4 or 6 piston calipers and fabricating my own brackets?? Then thats what it is.... My goal here, as with all my modifications, is to increase the performance, but do so on a moderate budget. Similar to the long travel control arms, I don't believe in paying someone for something I can do myself....

View attachment 453124View attachment 453125

In case you didn't come back to this thread, 18" wheels work fine with 4 piston 2019+ front GM calipers: parts no 13545382 and 13545383. There are even very cheap aftermarket versions on amazon: https://www.amazon.com/Premium-Compatible-Chevrolet-Silverado-2019-2020/dp/B0CDKG23KN

 

[5StarCustmSolutns]

In case you didn't come back to this thread, 18" wheels work fine with 4 piston 2019+ front GM calipers: parts no 13545382 and 13545383. There are even very cheap aftermarket versions on amazon: https://www.amazon.com/Premium-Compatible-Chevrolet-Silverado-2019-2020/dp/B0CDKG23KN

Thanks for the info..
Sometime in the very near future I'll pull my truck into SpeedShop 2120(aka my garage) for a couple weeks worth of work... Whle the calipers are off, I'm planning to see how a pair of front 2 piston calipers might could work on the rears?? See if I can't fab my own brackets and make that happen??

That's the most cost effective (bang for buck) option I had come up with..

However, you just made me think outside the box a little there.... It would make sense for me to buy a couple different 4 piston calipers and see if I can make them work front and/or rear??
** I realize that might not read well to some, but I'm not advocating anyone modify or change anything with their brake system, I'm strictly talking about ways I might be able to increase the braking performance on my personal custom Off-Road rig **
My PowerStop rotors have been on for 6-7 years now....been turned once. I've had a brand new set of OE rotors laying in my shop for almost 2yrs now, and have &0 dollars in them. Was planning to slot/dimple/install them while truck was in....be nice to add some better calipers same time??

Or at the least some better seals? Has anyone ever heard of any high(er) performance caliper seals for the GMT900?



EDIT: I just realized there was a link in your post (got up too early lol). When I clicked on it my first though was how much those look like the two piston OE calipers on my truck now? Then it occured to me that: The 4 piston and 2 piston calipers should be the same height, or VERY close to the same height? With the 4 piston naturally being wider..
So I checked rotors and the 19-20 is 15mm larger, so 7.5mm per side... I have well over 7.5mm to spare between my calipers and the inside of my 17" wheels. It's hard to measure but I would say I have 18-19mm?
The derterminate is going to be how much further the 4 pistons protrude out past the face of the rotor -vs- my +18 offset/backspacing?
Off the top of my head, I think they're gonna be fine!?!? OE offset was +24.. Hard to imagine GM engineers approving a design with a 6mm or less gap between the edge of the caliper and the back of the wheel?

Man, moving the 2 piston calipers from the front to the back and buying a pair of 4 pistons for the front would be a serious bang for the buck upgrade





EDIT 2: Found these specs on the (proclaimed) only ALL AMERICAN MADE performance brake upgrade manufacturer's website, these guys here >> https://ssbc-usa.com/
These are a 6 piston front caliper.. And a 4 piston rear.. And cost close to $5k lol.. But do look like the may be the option that is the most bang and the most buck?

I just wanted to put them here to give a visual for the clearnace concerns / measurements

 

[Davidj281]

I did the rear Baer brake rotor upgrade with the stock calipers and EBC orange pads and it stops very well. I also have the 6-piston/16”” PPV setup on the front (EBC orange) and overall the brakes are quite a step up from stock. Have SS brake lines all around too. Was going to try the SSBC calipers in the back one day. Has anyone used them?

 

[Doubeleive]

Just wanted to ask as Ive been on 4 sets of scales in the last few weeks and am averaging 3400 front axle and 3480 rear axle...
We had another 24hrs of Appalachia Off-Road Rally last weekend; and I had a several mile stretch (again) at the end of a long long downhill traverse with 16-18? very low speed corners, in which I had to resort to a slow cruising pace because of the overheating of my brake system.. Im inclined to think it's a little bit fluid related, a little bit rotor related, a little bit pad related, and a little bit caliper (design?) related...

Front: currently running 6-7yr old Power Stop Z36 calipers(OE core returns that get cleaned and painted). I replaced the seals, pistons, pads(Z36) and turned rotors 16 months ago

Rear: OE calipers, bought new 16 months ago, with Power Stop Z36 pads and rotors
-R rear is currently sticking, AGAIN. For the third time in last 5yrs, and on 2nd caliper.

Fluid was also flushed 16 months ago..

[ To avoid another long explanation of a lessen learned the hardest way, here are the cliff notes: Replaced rear calipers as pair after breaking off stuck bleeder bolt in Z36 caliper.....it's what I do....special talent I was born with....many years ago earned nickname BoltBreaker 5000 lol. I'm sure most who read this will naturally think: A guy who earns that nickname is very good at drilling and tapping......no that does not apply here either.....or at least it didn't as of 16mos ago.....or maybe better said patience when drilling and tapping did not yet apply here 16mos ago!
Now have drill press, proper vice, cutting oil, decent drill bits, and may be ready to get over the hump ]

Could the dual piston rear help? or am I going to have to go deeper, with a more expensive upgrade?

I have found using the tow/haul feature works exceptionally well for high speed down hill curves, takes a lot of the load off of the brakes.
your 2011 should have the grade-braking feature with the tow button on.

 

[strutaeng]

Do the GMT900 1500 SUVs not come with rear 2 piston calipers? I assumed they did?

I did the 2019+ 4 piston calipers on my 99 Silverado recently. I'm running some 2014-ish Tahoe 18" wheels. I had to do some grinding on the calipers because they were hitting the inside of the rim. I've put about 1,000 miles and it's working fine. The upgrade is pretty worth it. 6 piston calipers was another option but kinda spendy.

My buddy told me you can put some stock Corvette rear (4 piston?) calipers/rotors on our 10 bolts, with some custom brackets they make. Our 99-04 Silverados come with rear disc, single piston calipers, so I imagine it will be a huge improvement. I assume the Corvette upgrade likely also works on the GMT900 SUVs?

A rear axle swap from the k2xx is yet another option. I have one of those axles I want to swap in my truck. The brakes are single piston calipers, but larger rotors. Bonus is larger axle. Or larger brakes, however you look at it.

I really like how GM has designed these brake systems where there's so many options for interchangeability. It's kinda crazy. High performance brake upgrades using factory parts. I'll take it!

 

[Marky Dissod]

Do the GMT900 1500 SUVs not come with rear 2 piston calipers? I assumed they did?

THINK that GMT800 SUVs - but not necessarily GMT800 pickups - came with rear 2 piston calipers,
which is why I've not bothered upgrading the rear brake kit on my Tahoe.
If I do, it'll be a GM OE upgrade though.

I really like how GM has designed these brake systems where there's so many options for interchangeability.
It's kinda crazy. High performance brake upgrades using factory parts. I'll take it!

Somewhere I read that the AVERAGE age of the used cars in America is about 16 years old.
Given how many GMT900 / GMTK2xx / GMT T1xx parts are compatible with GMT800s & even GMT400s,
we all need to become better-versed in the available GM OE upgrades for our vehicles,
so we can collectively push that average age up higher by improving our vehicles with GM OE parts.

 

[5StarCustmSolutns]

Given how many GMT900 / GMTK2xx / GMT T1xx parts are compatible with GMT800s & even GMT400s,
we all need to become better-versed in the available GM OE upgrades for our vehicles,
so we can collectively push that average age up higher by improving our vehicles with GM OE parts.

Im in! Im not a believer that GM OE is the best option all the tiime, because I know auto engineers are handcuffed with a budget and sometimes forced to make concessions. I look at upgrades on an individual basis and how they work for what's needed to achieve the ultimate goal. But I'm 110% willing to try and help find GM OE upgrades for our older platforms from the newer models...

 

[5StarCustmSolutns]

Do the GMT900 1500 SUVs not come with rear 2 piston calipers? I assumed they did?

I did the 2019+ 4 piston calipers on my 99 Silverado recently. I'm running some 2014-ish Tahoe 18" wheels. I had to do some grinding on the calipers because they were hitting the inside of the rim. I've put about 1,000 miles and it's working fine. The upgrade is pretty worth it. 6 piston calipers was another option but kinda spendy.

My buddy told me you can put some stock Corvette rear (4 piston?)

My 2011 GMT-900 (Avalanche LTZ) came *single piston rears...

That is exactl what i was wanting to do, but when I got involved with this non-profit and the extreme off-road capability needed to help how I wanted to be abe to help, I took off my 20" Raceline's and put on some 17" Methods.... From what I've been able to discern to this point, there are no cost effecive upgrades that will work with 17's??

Do you know if the Vette upgrade is possible with 17's??

*edit