Gm Brembo upgrade added...sluggish acceleration and much lower mpg.

[Tahoered]

Hey Guys. So dealership is doing the warranty work to replace rear drivers side caliper. This is the same side with the higher temp and the grooves. I also do not feel this is the ultimate fix. I sense if that rear side was the only one dragging I would maybe experience a bias on the steering towards one direction or another, however the steering is straight when I let it go. The brakes are gm performamce brembo front and rears. The same type they place on the ppv vehicles with the exception of it being red vs black. In the rear calipers, there is this black box-module for a lack of words attached right to it. Easy access. It has a cord plugged right into it that one can easily unplug. Seems to me that it would be related to the electronic braking system. I am extremely tempted to disconnect them and try driving it on some wide open field with no traffic or potential for accidents to see if there is any difference. Researching more on this gives me the impression if the brakes were dragging, the heat would be much higher and more noticeable either by smell or touch. I will attempt disconnecting those rear plugs and report back. Sorry for the long gaps in update. Those calipers are on back order and may take awhile before I actually receive a new one. I'll report back after unplugging what "seems" to be an electronic connection to the rears. I feel this smaller Chevrolet dealership must have had some journeyman that Saturday that it was installed doing the work. I am tempted to travel to the larger dealership I purchased the vehicle from (2 hours away) to look over the whole braking system or find a culprit. Suck part is the distance, travel, cost and potentially getting the run around like previous dealership if they can't figure it out the first time. Will surely report back soon.

 

[Doubeleive]

The T2's have a brake pad sensor which is probably the black box & cable you are referring to unplugging it should have no effect on braking and if anything it will cause a error message, just like if the abs system is not working the brakes will still work you just wont have abs.

 

[Stbentoak]

60 degrees difference is almost a complete moot point.

Ive had brake calipers stick in the past. The last one that i actually measured with my infrared gun was over 700 degrees. And that was on a little minivan in which i honestly couldnt even hardly tell it was sticking as far as driving went…other than the burning hot smell lol.

Yep , I've had sticking calipers before too, and if they are really sticking you will feel it and smell it pretty quickly.....

 

[66 Galaxie]

Another possibility is the tech fubared the brake line on the left rear caliper.

Some techs clamp rubber brake lines when changing calipers. This can be as bad as a rubber brake line that was kinked which essentially bruises the internals of the rubber brake line and can cause a one way valve area in a rubber brake line. High pressure fluid will go to the caliper but stays under pressure after brake pedal is released. I had this happen on a front brake caliper years ago. Interestingly enough there was no directional pull caused by the dragging caliper when I experienced it.

Here’s a short write up that mentions it: https://www.techshopmag.com/imploded-brake-hoses-and-hidden-symptoms-not-easily-diagnosed/

 

[Tahoered]

Another possibility is the tech fubared the brake line on the left rear caliper.

Some techs clamp rubber brake lines when changing calipers. This can be as bad as a rubber brake line that was kinked which essentially bruises the internals of the rubber brake line and can cause a one way valve area in a rubber brake line. High pressure fluid will go to the caliper but stays under pressure after brake pedal is released. I had this happen on a front brake caliper years ago. Interestingly enough there was no directional pull caused by the dragging caliper when I experienced it.

Here’s a short write up that mentions it: https://www.techshopmag.com/imploded-brake-hoses-and-hidden-symptoms-not-easily-diagnosed/

Thank you...will definitely show this to them as a possibility!

 

[mb1500]

To my knowledge all of the 21+ have the electric parking brake, the black box on the back of the rear calipers. Like you mentioned I too wonder if unplugging would have an impact on your issue, but you would obviously lose the parking brake function entirely.

 

[Tahoered]

Hi Guys. Back for an update. So I dropped the vehicle off yesterday for them to replace the rear drivers side caliper which they claimed was the culprit. Just picked it up this morning and now back home (about 5 - 7 miles away). Happy to report car is back to normal. It can now coast! Mpg seems to be back to normal thus far (way too short of a distance traveled to truly compare) and my acceleration is no longer labored. According to the techs worksheet, there was binding and the temp readings which he repeated again consistently read much higher at that wheel. They claimed to have checked all 4 corners. Not saying I do not believe them, but I'm certain the "check" on the other corners were minimal. This is a small dealership and they seem to need help with their service department. I can now truly enjoy this car again and hope to not experience such a headache with brakes. It's unfortunate the service advisor or the tech who worked on the car was not present (picked up car 7:30 am). Really wanted to get a more detailed explanation. Tbh, want to know if it was a possible defective caliper or installation error, etc. They would never admit if it were an install error imo. Just happy to report the car is back to normal. Thanks to you all! My arguments at that dealership was mainly the comments I received here. You guys saved me because I spoke as if I truly was a mechanic. Thank you.

 

[2008yukonxlslt]

So glad you got her working!!
I once had a dragging rear brake on a 3 yr old 91 ford explorer. Two dealerships tried to trouble shoot, first said they couldn’t find anything wrong and then second dealership called me after I dropped off and said brake calliper was seized, I said ok and authorized the repair but I was suspicious as this was a 3 year old vehicle that I bought new and had never had any issues, I told them to be sure to save the defective brake calliper cuz I wanted to see it myself, 30 min later, dealership called me and said brake calliper was not seized. Ended up being a binding short rear parking brake cable on the drivers side. I bought the replacement cable from ford for $15 and replaced in the drive way in less than an hour.
Not sure if you had to foot the bill for the repair but I learned from my experience that I want to see the defective parts if I am paying for the repair, you have the right!!

 

[Tahoered]

So glad you got her working!!
I once had a dragging rear brake on a 3 yr old 91 ford explorer. Two dealerships tried to trouble shoot, first said they couldn’t find anything wrong and then second dealership called me after I dropped off and said brake calliper was seized, I said ok and authorized the repair but I was suspicious as this was a 3 year old vehicle that I bought new and had never had any issues, I told them to be sure to save the defective brake calliper cuz I wanted to see it myself, 30 min later, dealership called me and said brake calliper was not seized. Ended up being a binding short rear parking brake cable on the drivers side. I bought the replacement cable from ford for $15 and replaced in the drive way in less than an hour.
Not sure if you had to foot the bill for the repair but I learned from my experience that I want to see the defective parts if I am paying for the repair, you have the right!!

Thankfully I did not have to pay anything. I bought the parts from a company called 404parts. Great guys over there and they sell OEM parts. They did not hesitate communicating with the dealership to provide proof of purchase, invoice #, warranty info etc. Dealership ultimately replaced it under warranty. That company will definitely get my business again.

 

[steiny93]

So how much did your mileage go down due to the added rotational weight? [reference to the earlier posts about that being the cause]

 

[olyelr]

So how much did your mileage go down due to the added rotational weight? [reference to the earlier posts about that being the cause]

It wont go down at all. Its a moot point. It wasnt due to the added weight.

 

[DuraYuk]

So how much did your mileage go down due to the added rotational weight? [reference to the earlier posts about that being the cause]

No his mileage went down because 1 caliper was sticking and dragging the car down substantially all while having a very minimal amount of temp difference and no pulling if you can believe that !

Or that's just what the dealer said lol.

 

[steiny93]

my sarcasm was missed on the above 2 replies

 

[DuraYuk]

my sarcasm was missed on the above 2 replies

My reply was also sarcastic as there are guys here who don't know the difference of sprung and unsprung weight and how much of a difference rotational mass can make.

But no need to argue when the material isn't fit for the group listening. Glad OP got it sorted.

 

[olyelr]

My reply was also sarcastic as there are guys here who don't know the difference of sprung and unsprung weight and how much of a difference rotational mass can make.

But no need to argue when the material isn't fit for the group listening. Glad OP got it sorted.

I know exacting how unsprung weight can change vehicle handling. But, I mean, how much more do these super huge brakes actually weigh in comparison to the factory ones? Is it really even that much?

I have changed wheel and tire packages on vehicles that have an added weight difference of 50 pounds more, and the tires were also taller…both of which would make a much bigger difference in rotational mass than what heavier brakes ever could. While the change is certainly noticeable, it didnt make the vehicle terrible to drive.

Theres just no way a slightly heavier brake setup would absolutely kill vehicle performance like the OP was experiencing.

 

[DuraYuk]

I know exacting how unsprung weight can change vehicle handling. But, I mean, how much more do these super huge brakes actually weigh in comparison to the factory ones? Is it really even that much?

I have changed wheel and tire packages on vehicles that have an added weight difference of 50 pounds more, and the tires were also taller…both of which would make a much bigger difference in rotational mass than what heavier brakes ever could. While the change is certainly noticeable, it didnt make the vehicle terrible to drive.

Theres just no way a slightly heavier brake setup would absolutely kill vehicle performance like the OP was experiencing.

No one is saying it will be a crazy difference. But it can be noticeable. Clearly OPs problem was elsewhere but is still something to think about.

Its been beaten to death in this thread. So id rather not keep that chain going.

 

[olyelr]

Haaaaa gotchya. I thought u were insinuating that his problem was the added weight of the brakes. I agree, a lot going on in this thread!

 

[brucemac]

Hey, I have these on order and am anxious to install. In the notes it says that the break wear indicator has to be turned off. Anybody know how you do this? Is it more to point out that that piece of telemetry is inaccurate, or is it legitimately something that has to be turned off? If so, does it have to be performed by the dealer, or can the customer do this in the field?

 

[Rocket Man]

My reply was also sarcastic as there are guys here who don't know the difference of sprung and unsprung weight and how much of a difference rotational mass can make.

But no need to argue when the material isn't fit for the group listening. Glad OP got it sorted.

Oh boy.

 

[DuraYuk]

Oh boy.

The ignorance here is palpable lol. 20 pages on floor matts, turns out everyone just installed them incorrectly lmao.

I forget this isn't a enthusiast forum like im used to and most have never worked on their vehicles before.

Makes the experience better with that realization.