4 Piston Big Brake Upgrade from 2019-20

[Dantheman1540]

Yes, you may be right, but this is the 2000-2006 section of the forum. So this thread was started to suggest an upgrade to the GMT-800 2-piston brakes which are grossly inadequate. The GMT-900 already had larger brakes (and rotors, I believe) so I wouldn't have expected as much difference. Plus, if you just put them on yesterday, are they even burnished yet. If not, they will probably improve over the first couple of weeks of driving.

I totally agree with SRQ that they will get a little better as they wear in. I was surprised at how little of a difference they felt at first but after a few weeks, they seem much more effective.

But still, they aren't gonna stop like hitting a wall.

 

[SRQYukon]

If anyone thinks this upgrade is going to be equal to Brembo or Wilwood big brakes with 6-pistons and mega 16" rotors, then they're engaging in wishful thinking. But for those that want much better braking for less than 1/2 the cost of these aftermarket brake kits, it's an option. Once I get mine installed and dialed-in, I'll post a comparison between the original GMT-800 brakes and the 4-piston upgrade.

 

[1BADI5]

I just installed these brakes on my dad’s 2012 yesterday. I drove it and they do feel better than the stock GMT-900 brakes but it isn’t a massive difference like going to the Brembos. If you’re expecting Brembo performance from these, you will be disappointed. They are an upgrade but it isn’t worth buying new wheels just to fit these brakes in my opinion, they aren’t that good. We already had AT4 wheels on his truck so it made sense. I will not be bothering with these for my Yukon since they don’t work with my wheels. I suspect similar performance could be had with EBC Yellowstuff pads in the stock 900 brakes.

Now throw some YellowStuff pads in those new calipers, bet that would be a solid set up.

 

[ivin74]

I think this might be the route i will go........unless someone else wants to be the 99-13 guinea pig???

I had a buddy of mine do the ctsv brake conversion and he stated that the ctsv brake pads had less contact surface in his Siera brake rotors. Not sure how much effect that would make on stopping these 5k lbs rigs. Something to think about.

 

[lucas287]

On a different forum a self-proclaimed brake expert (worked in the industry for decades) chimed in about this new setup. My biggest takeaway from his contributions were that he was really impressed with the GMs new brake pad formulation. He claims that it's one of the highest friction coefficients to come on an OE-vehicle - HH. As others have mentioned before, these new ceramic pads will require quite a bit of break-in with that level of friction. But - should be excellent once fully bedded.

I propose that anyone who leaves a review of their thoughts also share the specific pads they used since we all know how big of a factor that plays.

Side note - i'm not a Tahoe, or Yukon, guy. I have a '16 Silverado with the little 6.2. I have all the parts sitting in the garage waiting for some free time so I'll be sure to share my thoughts when the time comes!

 

[91RS]

I’ve never had brakes improve a noticeable amount after being bedded in but regardless I was comparing the stopping power to the Brembos which stopped significantly better from mile 1 (I was comparing to the Brembos because I believe someone was saying earlier in this thread that these brakes should be close in performance and they are not). I understand the forum I’m in. I said these brakes are better than the GMT-900 brakes BUT aren’t a value if you have to buy wheels just to fit them. Unless you were already buying wheels anyway, just get the GMT-900 brakes and Yellowstuff pads.

 

[SRQYukon]

I completed the 4-piston upgrade this weekend. So far I'm impressed with the performance, though not able to thrash it much yet. Since we also replaced the rear differential at the same time, I'll need to complete the break-in before I see how it works for trailering. For the cost, I say it's well worth the investment. I cannot comment on comparisons to Brembo, Wilwood, Baer, or other big brake upgrades, because I've never had any of those. Here are some observations:

It was actually one of the easiest upgrades to do.

The whole installation took about 2 hours, which included replacing the brake lines and bleeding the system. That's with an assistant for the bleeding. This assumes you've test fitted your wheel and there are no clearance issues. I had already spent another three hours ahead of that smoothing the calipers and painting them.

I did go with R1 Concepts drilled and slotted rotors and their Optimum OE pads. I doubt that adds much beyond stock braking performance, but I've had better success with d&s rotors when it comes to warping from heat. The set I took off had 130k miles and had never been turned and were still running true.

The only tricky part is getting the calipers centered. One standard washer was not enough, and two were too much. We scouted around and found some thinner washers and put 1 thick washer and 1 thin one. That was perfect. So if you do this, have an assortment of 1/2" washers of varying thickness on-hand to try.

I'll post more later, once I have used them for a while under varying conditions. I won't mess around with measuring stopping distance, but I will post my review based on my driving experience compared with the previous 214,000 miles with the stock brakes.

 

[Fjs0001]

I made some 0.133" spacers to center my calipers on the rotors. For mock up, I stacked 0.365" of washers to use as wheel spacers and the 2010 22" Escalade wheels are 0.14" away from touching the bump on the caliper.

The caliper bump is 0.3" tall, so if I grind it off I should be about 0.075" away from the caliper without using spacers. How close is too close? I think I can only get away with a 1/8" wheel spacer and still have proper support between the hub and wheel. I don't care about these rims enough to spend big money on spacers. I'm going to grind down the calipers unless I find a used set of spacers somewhere.

Now I'm trying to decide if I want to powder coat these calipers or just spray paint them.

 

[Dantheman1540]

These brakes impressed me again last night, I was coming home late and admittedly looking at my laptop when the car in front of me stopped at a green light for no reason. luckily I saw the brake lights and had more than enough time to stop but since I was startled at the odd event I smacked the brakes hard and sent my laptop into the floorboard, kinda forgot how good these things are.

 

[SRQYukon]

I made some 0.133" spacers to center my calipers on the rotors. For mock up, I stacked 0.365" of washers to use as wheel spacers and the 2010 22" Escalade wheels are 0.14" away from touching the bump on the caliper.

The caliper bump is 0.3" tall, so if I grind it off I should be about 0.075" away from the caliper without using spacers. How close is too close? I think I can only get away with a 1/8" wheel spacer and still have proper support between the hub and wheel. I don't care about these rims enough to spend big money on spacers. I'm going to grind down the calipers unless I find a used set of spacers somewhere.

Now I'm trying to decide if I want to powder coat these calipers or just spray paint them.

I think you can go up to 1/4" without losing support. I've been running 1/4" spacers of the rear of my Yukon Xl and towing a 4000 lb. trailer several times a week (for a couple of years) without any issues. You really need to look at how much wheel stud there is beyond the lug seat. 0.14" clearance should be fine. I only have 0.125 and no issue in the first 150 miles. I don't think aluminum wheels have much flex even when cornering.

 

[Rocket Man]

The only tricky part is getting the calipers centered. One standard washer was not enough, and two were too much. We scouted around and found some thinner washers and put 1 thick washer and 1 thin one. That was perfect. So if you do this, have an assortment of 1/2" washers of varying thickness on-hand to try.

There are shims available, I know Wilwood supplies them with their kits. They're washers in varying thicknesses, some of which are super thin so you can center the calipers perfectly. It's an important step with this style calipers.

 

[SRQYukon]

Okay, so I'm ready to give a more complete review of the 2020-2021 upgrade to my 2003 Yukon. I have had the system installed for two weeks and have driven 473 miles as of today. As I mentioned in an earlier post, this won't be a comparison to the high-performance aftermarket big brake kits. Rather, I will offer my impressions in comparison with the original braking system. So here we go:

Overall braking performance: Very good. Zero brake fade, even with multiple heavy stops. When trailering, the brakes are super responsive with excellent control. A mechanic that works for my son-in-law described the braking system as progressive. I wasn't sure what he meant until I drove it a while. So, here's what I think he meant: When braking, I can use variable pedal pressure much more effectively. In other words, the harder you press the pedal, the more stopping power there is available. I suppose that every braking system does that to some degree, but this is much more noticeable. I have tried multiple repetitive hard stops from around 55 mph to zero mph, and I've never been able to get the brakes to lock up. I didn't measure stopping distance which I don't feel is that helpful unless there's a baseline for comparison. If I had to assign a percentage, I say around 20-25% improvement over the stock setup. The main improvement is in brake feel and clamping force which is very tactile (for lack of a better word). The force is very controllable with even slight adjustments in pedal pressure. There is noticeably less "nose dive" when hard braking, which surprised me, since the front brakes a so much larger (this may be, in part, b/c the new AFP Coilover conversion). I presume the original proportioning and master cylinder compensates well for the greater forces and fluid volume. The system played nice with the ABS system, as well.

Value: I spent around $1000 on parts for my brake upgrade which included drilled and slotted rotors front and rear, 2021 OEM calipers, and stock OEM rear calipers. I also upgraded to Goodridge SS brake line front and rear. Since I've already had one very minor accident due to the weak stock brakes, I consider this to be money well spent. This is about 25% of the cost for Wilwood 16" front/14" rears. What I gained were two extra pistons upfront and much larger rotors. My '03 came with 12" front rotors vs. the 13.5" 2021 rotors. The rears on the '03 are already 2-piston calipers, so no upgrade outback except the d & s rotor and SS lines.

Installation issues: None, really. The installation was very straightforward. Very much like changing the stock calipers were the last time I replaced them. Really, the only things that required tweaking are grinding the caliper shoulder and projecting casting, and getting the calipers centered with the rotors. I shaved around 3/16" off the shoulder and 1/8" of the raised casting. As it turned out, I really did need to shave the raised casting because it had plenty of clearance with mya wheels. RocketMan's suggestion of getting the Wilwood shim kit for centering is a good one. They are really just washers of varying thickness (around $12 for 10 washers from Summit). I suppose you may need two shim kits unless you happened to hit on the right combination with just four washers. I went the other route and just bought hardened washers from Lowe's. Dialing in the centering only took about 20 minutes on the first caliper and then it worked the same on the other side. As long as you have several thicknesses available, you should have no issues with centering. I did spend a couple of hours prepping and painting the calipers. That included grinding the inside shoulder and the raised casting, smoothing the rough castings, and painting the calipers (3 coats caliper paint and 2 coats clear). My installation required no wheels shims with this mod done. Of course, some wheels will likely require spacers. Mine are 22" snowflake OEM knockoffs. I have only about 1/16" clearance at the front shoulder of the caliper.

 

[ivin74]

Great write, do you have any pics of the shoulder are area you grinded off?

 

[SRQYukon]

Great write, do you have any pics of the shoulder are area you grinded off?

No pictures of the grinding. But the picture below shows the areas to grind. The larger area is what I refer to as the shoulder, the smaller arrow is the raised casting. You can see the radiused area is where the wheel is closest. That radius is already there, but needs to be beveled back. Most wheel spokes angle outward from the center hub and so is closest to the caliper at the shoulder. If I was doing it again, I would probably take a little more off the shoulder than I did. It's still pretty close to the wheel. It's a little difficult to test fit and get accurate measurements, but I would suggest doing that before grinding. It requires mocking-up the caliper and installing the correct wheel. If you allow time for that before grinding, it adds another couple of hours to the installation. I think I could have gotten by without grinding the raised casting, but I wanted to play it safe. If you look elsewhere in this thread you will see that some have completely removed the raised casting. I doubt that would be necessary with most larger wheels, but probably would be with some OEM wheels or wheels with small offsets.

 

[corvette744]

Okay, so I'm ready to give a more complete review of the 2020-2021 upgrade to my 2003 Yukon. I have had the system installed for two weeks and have driven 473 miles as of today. As I mentioned in an earlier post, this won't be a comparison to the high-performance aftermarket big brake kits. Rather, I will offer my impressions in comparison with the original braking system. So here we go:

Overall braking performance: Very good. Zero brake fade, even with multiple heavy stops. When trailering, the brakes are super responsive with excellent control. A mechanic that works for my son-in-law described the braking system as progressive. I wasn't sure what he meant until I drove it a while. So, here's what I think he meant: When braking, I can use variable pedal pressure much more effectively. In other words, the harder you press the pedal, the more stopping power there is available. I suppose that every braking system does that to some degree, but this is much more noticeable. I have tried multiple repetitive hard stops from around 55 mph to zero mph, and I've never been able to get the brakes to lock up. I didn't measure stopping distance which I don't feel is that helpful unless there's a baseline for comparison. If I had to assign a percentage, I say around 20-25% improvement over the stock setup. The main improvement is in brake feel and clamping force which is very tactile (for lack of a better word). The force is very controllable with even slight adjustments in pedal pressure. There is noticeably less "nose dive" when hard braking, which surprised me, since the front brakes a so much larger (this may be, in part, b/c the new AFP Coilover conversion). I presume the original proportioning and master cylinder compensates well for the greater forces and fluid volume. The system played nice with the ABS system, as well.

Value: I spent around $1000 on parts for my brake upgrade which included drilled and slotted rotors front and rear, 2021 OEM calipers, and stock OEM rear calipers. I also upgraded to Goodridge SS brake line front and rear. Since I've already had one very minor accident due to the weak stock brakes, I consider this to be money well spent. This is about 25% of the cost for Wilwood 16" front/14" rears. What I gained were two extra pistons upfront and much larger rotors. My '03 came with 12" front rotors vs. the 13.5" 2021 rotors. The rears on the '03 are already 2-piston calipers, so no upgrade outback except the d & s rotor and SS lines.

Installation issues: None, really. The installation was very straightforward. Very much like changing the stock calipers were the last time I replaced them. Really, the only things that required tweaking are grinding the caliper shoulder and projecting casting, and getting the calipers centered with the rotors. I shaved around 3/16" off the shoulder and 1/8" of the raised casting. As it turned out, I really did need to shave the raised casting because it had plenty of clearance with mya wheels. RocketMan's suggestion of getting the Wilwood shim kit for centering is a good one. They are really just washers of varying thickness (around $12 for 10 washers from Summit). I suppose you may need two shim kits unless you happened to hit on the right combination with just four washers. I went the other route and just bought hardened washers from Lowe's. Dialing in the centering only took about 20 minutes on the first caliper and then it worked the same on the other side. As long as you have several thicknesses available, you should have no issues with centering. I did spend a couple of hours prepping and painting the calipers. That included grinding the inside shoulder and the raised casting, smoothing the rough castings, and painting the calipers (3 coats caliper paint and 2 coats clear). My installation required no wheels shims with this mod done. Of course, some wheels will likely require spacers. Mine are 22" snowflake OEM knockoffs. I have only about 1/16" clearance at the front shoulder of the caliper.

Any upgrade to the stock brakes is smart their horrible.Question you state you have made several hard stops from 55 to 0 and cant get the brakes to lock up.I assume you mean cannot get the abs to activate.Were you able to get the abs to activate with the stock brakes.I installed calipers-rotors and pads from 08 tahoe and i can get the abs to kick in on hard stops everytime.I am the same just the 08 upgrade was about 25 percent better braking.Then after i installed the goodridge lines i put maybe another 10-15 percent better and stronger pedal.Im just wondering why you cant get the abs to kick in on a panic or emergency stop kind of defeats the purpose of having abs brakes.

 

[SRQYukon]

Any upgrade to the stock brakes is smart their horrible.Question you state you have made several hard stops from 55 to 0 and cant get the brakes to lock up.I assume you mean cannot get the abs to activate.Were you able to get the abs to activate with the stock brakes.I installed calipers-rotors and pads from 08 tahoe and i can get the abs to kick in on hard stops everytime.I am the same just the 08 upgrade was about 25 percent better braking.Then after i installed the goodridge lines i put maybe another 10-15 percent better and stronger pedal.Im just wondering why you cant get the abs to kick in on a panic or emergency stop kind of defeats the purpose of having abs brakes.

I wasn't saying that the ABS won't activate. I was saying that even on hard stopping the braking it is so superior, I don't think it needed to activate. I'm in a dense traffic area and haven't been able to get out of traffic or in a good situation to try a true panic stop. I will try to confirm the ABS operation when I'm in a safe place to do so. I'm assuming that if there was an ABS problem it would probably be throwing a code, though.

 

[Fjs0001]

What brand caliper paint do you all like to use? I want to paint my calipers grey and I also need to repaint the inner barrel of my wheels.

 

[SRQYukon]

What brand caliper paint do you all like to use? I want to paint my calipers grey and I also need to repaint the inner barrel of my wheels.

VHT SP732 Bright Blue Brake Caliper Paint Can - 11 oz

 

[Rocket Man]

VHT SP732 Bright Blue Brake Caliper Paint Can - 11 oz

VHT makes great paint. Their high heat crinkle is awesome on things like rocker covers or anything with casting marks.

 

[SRQYukon]

I haven't had the caliper super hot yet, but so far there's no evidence of overheating or discoloration with this paint.