4 Piston Big Brake Upgrade from 2019-20

[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.