groovy_moon

I have a 19 Suburban... Has the same brakes as the pre '19 trucks. Looks like TONS of wheel clearance and my 18" wheels look just like the 18" wheels on 19/20 trucks... Wonder if I will have no issues cause the wheels are the same Truck -> Suburban

If I am wrong about the lever effect we should prbably throw out 50% of all mechanical engineering ever done... and your won't need breaker bars to lossen stuck bolts anymore... that little 4" ratchet handle they sell at Murry's will be fine. They work better because the hydraulic system produces much higher force of the pads on the rotor than the rim brakes... there are material differences as well. .

Didn't read the whole article but I think they forgot about the booster's multiplicative and additive effects on the input to the master cylinder.. This is defined by the "jump in" of the booster and the "servo ratio" of the booster. The JumpIn is an initial bump up of the output force of the booster when the pedal is initially depressed (a few mm). The servo ratio is the multiplier of the booster on the input force from the pedal.... so the output of the booster approximately is: Output Force = (Input Force X Servo Ratio) + JumpIn Servo Ratio is usually in effect until input force on the brake pedal is about 200 N. That force is then imparted to the master cylinder pistons.

IMHO one of the big differences is in the friction level of the pads. HH is really high for a pass car lt truck lining. The fixed caliper adds to the stiffness.. I need to understand the piston diameter of the pre 2019 calipers to make a comparison there. It is possible that the surface area f the 2019-2020 fixed calipers is smaller with the increased friction making up for it.... this would also add to the stiffer feeling https://idpartsblog.com/2019/04/11/what-do-brake-pad-friction-ratings-mean/ Several of the Engineers I wor with have Pre 2019 GM trucks and most are going to do this.. I have an ex GM Executive lease 2019 Suburban we just picked up with the floating calipers and vacuum booster (same as 2018 and earlier trucks). This weekend I had my family and gear for a ski weekend ~800 lbs and the brakes do suck. So I am looking into it for the 'burb.

The friction material may have a big part in that. Some high performance linings do not achieve max friction until they get very hot.

"Bedding In" is best done with easy driving for about 50 stops or so. When we "burnish" pads for testing we make 200 stops from about 50 mph to 0 at about 0.3 g every ~1-1.5 miles. This is a little bit more aggressive than what you would do approaching a stop sign. The most important thing is not to get them really hot when they are new. Some heavy duty linings like the kind found on Camaro SS's or Mustang GT's with the Brembo package can take longer to achieve a stable friction level.

Yeah... They probably show their benefit (drilled/slotted) at very high levels of performance.. Like "track Day" on an actual track on a fast car.. They look really cool too ... For normal daily driving.. not sure there is any benefit... Drilled/slotted rotors are promoted by Marketing Engineering to the general public. I put them on my Acura TSX (Cause they look cool) and for the type of driving I do I noticed nothing (they do make a faint whirring noise under braking)...

Flushing the system is a good thing every 2 years or so. Easy to do. Suck as much fluid out of the reservoir as possible. Fill it with fresh fluid. Starting with the caliper farthest away from the MC pump fluid thru until clear.. go all around.. keep an eye on the level... Your welcome. I would love to share actual real data but it is all proprietary and I could lose my job...I can share my conclusions and be vague about the actual makes and models... I think you put the source and part number for the SS braided hose... thanks in advance!!

AWESOME... That is the factory OEM material on 2019-> Sierra/Silverado 1500. It is made by "Galfer". 9130 Is a Non Asbsestos Low or NO copper "organic" lining. It will have a low or nbo metal (steel) content.. which is good for rotor life. . It has an HH friction rating. That is pretty high... Galfer at the moment may be a division of ITT. Galfer makes brake stuff for everything ... even bicycles. USUALLY the OEM's will have a "Value line" of brake pads they will sell and call them "OEM Equivelent" or whatever, but they are not the exact same material as the vehicle was originally built with. These trucks may be so new that they have not qualified an OES (Original Equipment Service) friction material yet (or they never intend too).

If the brake pads did not say GA9130 HH in the upper right hand corner on the back of the pad... you did not get the OEM original friction material for that caliper.......The HH stands for the friction level and is about as high as I have EVER seen in my ENTIRE 30+ year career as a brake systems and components Engineer. This may have had an effect. ALSO.. sometimes these Hi friction level pads can take a while to burnish in and achieve 100% contact and a stable friction level.

Absolutely and Definately flush out your brake fluid. GM fluid has been poor quality when compared to others. Even name brand aftermarket is better and Toyota fluid is the BEST. I know I have seen the actual test data. ALSO.. you brakes will need a little time to brake in an get full contact. ALSO... Try stainless braided jounce hoses... ..

AND .... Modern (or even a few gens ago) vehicles have not had prop valves for YEARS AND YEARS.... Since virtually the DAWN of ABS they have had EBD... Electronic Brake Distribution. Trust me on this one.. I have been testing brakes and running system development programs at tier 1 & 3 suppliers for decades.

Not true... Increasing a rotor diameter by as little as 1" can increase the effective radius significantly. This increases the lever arm on of the caliper around the hub and the output torque of the brake can be increased by 10% or more. The increased rotational inertia of the rotor (due to the larger diameter and slight increase in weight), although it does make it very slightly harder to stop the rotor, is insignificant compared to the overall inertia of the system (entire vehicle), and the increase lever arm MORE than makes up for the increased inertia. Most OEM's try and keep rotor size/weight down for: BIG #1) COST, #2) Handling Considerations, almost meaningless in a truck #3) Wheel size packaging.

No they do stop better.. I have tested all sorts of brakes and installed and tested (with real live data) several prototypes of "Big Brake" mods for OEM manufacturers. Wheel size is irrelevant. What IS important is Rolling Radius (The distance from the center of your hub to the ground)... So in some cases people put on big wheels and then a low profile tire and their rolling radius is VERY close to the original design... OR you have guys that put HUGE tires on lifted trucks.. then the rolling radius is much bigger and the brakes have to put out proportionally more torque to get the same "retarding force" on the road. Also.. compared to the inertia of the vehicle as a whole... the rotational inertia of the wheels is probably minimal. Holes and slots kind of look cool... for daily driver they are debatable. You Buddy's track car may also be VERY light and if it's a short track circle track car.. it isn't really going very fast... KE = 1/2mV^2... V^2 is the BIG factor in Kinetic energy here.

There haven't been prop valves in modern vehicles in a long long time (since virtually the dawn of ABS in the 80's for some).. They all have EBD.. Electronic Brake Distribution. The ABS system will cap the rear pressure when it detects impending wheel slip... as deceleration is increased it will drop the rear pressure and then rebuild it.. I know.. I am a brake systems engineer with 30+ years. EBD is WAY WAY WAY better and safer than prop valves on so many levels. I know exactly where those calipers come from but I ain't saying and it ain't no Isuzu

Ummmm The clamping force is not doubled... Theoretically... the Force of a 2 piston floating caliper and a 4 piston fixed caliper are the same as long as the piston area of the floating caliper is the same as the piston area of 2 of the pistons on one side of the fixed caliper.... HOWEVER: 1) The fixed caliper is generally significantly stiffer than the floating and therefore does not deflect and consume fluid (mushy long pedal) like a floating 2) Running clearances can be tighter and therefore improves initial stroke 3) A fixed caliper has no frictional losses in the pins (because it has none) and fewer in the abutments So A fixed caliper may have higher clamp loads... but only by a small amount. The BIG difference is in the caliper's overall stiffness. Also.. If the total piston area on one side of fixed caliper is more than the total piston area of the 2014-2018 floating caliper then there will be higher clamp load per PSI of pressure If the "effective radius" (size of the lever arm of the brake) is even a little bit bigger... then It can make a considerable difference. Also.. I believe that the friction that goes into that caliper OEM is rated as "HH" this is VERY high friction level for a Pass Car/LT friction material...

Again.. the dealership I brought mine to today said "no problem found" and then I got a NASTY phone call from the service manager in response to my email to the service writer saying it was not fixed and that there most certainly is a problem. If they had scanned and found codes they should have said so on the paperwork.

They don't take the time to check them.. or most don't... They won't do ANYTHING unless (1) GM says it's a real fix with a TSB and/or (2) They are actually one of those 1 out of 100 stealerships that actually cares bout their customers and has the " I would rather make $5 from you 3 times than $10 once" attitudes.

Excellent information and is the answer to what would have been my next question.

At least your dealer is going to do something. The one around the corner from my office said "no issue found" and when I wrote them a letter saying the problem was still there and being a little bitchy about it the service manager called me and told me (in so many words) to F off and he would not look at my Suburban again... This is the single WORST GM dealership I have ever run across.. Bob Jeannotte;'s in Plymouth Michigan. This is not the 1st service issue I have had with them. It's the 3rd. Who is your dealer and where? I am going to take it to one closer to my house...

Thanks. This is "Blue Driver"... $99 from Amazon? I have a lower end OBD II scan tool. I may try that first and see if it picks up anything. Did you get have any lights on the dashboard before before you used the BlueDriver scan tool? BTW one of my colleagues has a 2019 Tahoe and he says it starts from 150' away from inside the building no problem every time.

I have the same issue with a 2019 Suburban I just bought. Took it to the dealer around the corner from my office 1st thing this AM out of convenience. I showed them the bulletin, PIT5665. They basically pretended to have never heard of the issue... BULLSHIT They told me they were done just before lunch. I picked it up and they said "no trouble found".. BULLSHIT... $46,000 worth of BULLSHIT. I should have known better... A kindergarten class could provide a better source for mechanics than this place... They SUCK.. And I have had bad experiences with them in the past. I demonstrated the issue... the service writer ignored me and then after pushing the button like 20 times it worked and he looked at me and said.. see it's ok... try new batteries... I put in new batteries in and nothing, no improvement. I am taking it to a different dealer. Also I am going to video tape this issue. This is CRAP. My 2013 Sierra has remote start and it works from inside my building 50 yards away from it. (With aftermarket fobs no less) Has anyone had a dealer replace the Antenna Amplifier like it says in the PIT? Did that fix it? Luckily my neighbor's kid is the service writer at the next stealership I am going to and he may be a bit more receptive to actually DOING SOMETHING!!! The part that REALLY sucks that if this does not get resolved it will DESTROY the resale value of the vehicle.