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I am changing out the rotors (Girodisc) & pads on my C8. I wasn’t thinking took the front rotors off & then remembered something about having to disconnect the battery. Did I just screw up?
People have reported changing discs and pads without disconnecting the battery and had no negative effect.
RETRACTION - although some people have reported no issues after changing pads and/or rotors without disconnecting the battery, it appears the battery SHOULD be disconnected before performing those actions.
Last edited by BIG Dave; May 16, 2021 at 09:54 PM.
just got a service manual cd from ebay (boot leg?)here you go .good luck carl
"The battery must be disconnected to prevent the brake master cylinder from pressurizing the hydraulic system during its automated self diagnostic
tests that can possibly occur when a door is opened or the key transmitter is activated. Failure to follow this precaution may cause personal injury."
Important: The battery must be disconnected to
prevent the brake master cylinder from pressurizing the
hydraulic system during its automated self-diagnostic
tests that can possibly occur when a door is opened, or
the key transmitter is activated. Failure to follow this
precaution may cause personal injury. This needs to be
done whenever servicing the brake components. This
includes brake pads or rotor replacements. Failure to
disconnect the negative battery will also lead to a DIC
message that reads “Brake System Failure 62 MPH Top
Speed” (or metric equivalent, 100 km/h).You will also
notice the brake pedal feel is incorrect too.
Battery must be disconnected, just as others have posted from the repair manual warning.
If you are doing the rear rotors as well, you will need to head to the dealer and have the parking brake re-calibrated.
Park Brake Calibration
The park brakes do not require calibration often. Park brake calibration may be required after certain service procedures are performed. Some of these procedures are as follows:
Park brake actuator replacement.
Rear brake pad replacement.
Rear brake rotor replacement.
Rear brake caliper replacement.
The park brake calibration procedure can be completed using the following steps:
Block the drive wheels.
Install a scan tool to the vehicle.
Turn the ignition switch to the ON/RUN position with the engine OFF.
Select Configuration/Reset Functions from the Brake System Control Module menu.
If available, perform the Parking Brake Calibration procedure.
If Park Brake Calibration is not available, proceed back and select Control Functions.
Perform the Deactivate Rear Park Brake Service Position function.
Apply and release the park brakes using the park brake switch to ensure that the system is functioning.
Looks like I just made the same mistake on my C8. I Replaced the pads front and rear and never disconnected the battery. Now I start the car and I get brake failure speed limited to 43mph and service ESC. Also a clicking sound (like hazzards blinking) when I hold the brake down.
Question? Where you able to reset it by disconnecting the battery after the fact? Or did you have to take it to the dealer?
FWIW, disconnected battery when I changed my pads as a precaution. As it was warned, if opening a door when the pads are out of the caliper the electric motor that operates the ~3000 psi hydraulic eBoost could activate. When that happens the brake pad pistons will come out with a lot of force and brake fluid all over! NOT FUN!
I just replaced front and rear pads with Carbotech pads and even though I disconnected the battery I got a brake system failure warning. I’ll talk to my dealer tomorrow. I wonder if lifting it so high at the front, about 30 cm (12”), caused the issue, it did cause lift fluid to leak out.
^^^^
Don't see how lifting high would cause anything. Also surprised the lift reservoir leaked past the cap more than a few drops.
FWIW i.e. the Lift Reservoir. I made a pic of my history and info from having my Blue Cap installed on May 5th.
As noted I replaced my original OEM cap in January soon after leaks were discovered AND it was recommended a new cap be installed. Had my dealer buy a new cap, but the same part number as the OEM. I installed a wrist sweat band just in case as I had found a small amount of brake fluid on the top and sides of my reservoir. I checked the sweat band that was over the replaced original cap and found zero fluid. So for ~4 months with many accelerations that forced brake fluid up under the cap nothing. Appears to me some OEM caps had a ticker gasket and/or the reservoir plastic that pulls the cap tight could have been ticker and pressed the diaphragm/gasket tighter.
Sounds like you need the Blue Cap which has been reported has a thicker gasket in addition to no bleed air passage.
Let us know what the dealer indicates and the resolution.
[The error codes will clear if you hold the brake pedal to the floor for 1-2 min.
QUOTE=rob20rx7;1603238656]Looks like I just made the same mistake on my C8. I Replaced the pads front and rear and never disconnected the battery. Now I start the car and I get brake failure speed limited to 43mph and service ESC. Also a clicking sound (like hazzards blinking) when I hold the brake down.
Question? Where you able to reset it by disconnecting the battery after the fact? Or did you have to take it to the dealer?[/QUOTE]
[QUOTE=dfettero;1603462832][The error codes will clear if you hold the brake pedal to the floor for 1-2 min.
Is there any truth to this? Didn’t work for me. I updated my Autel scanner and though there seems to be the necessary updates to reset the 43 mph error, I can’t get it to reset.
Somewhere I read that there needs to be a hydraulic pressure test done by scanner (which the latest autel update has) before you can reset. My scanner performs the test but ends with “unknown error”.
I also believe some people that still get the 43 mph brake failure despite disconnecting battery are getting the msg because they should have pumped the brakes to seat the pads before reconnecting battery.
This is stupid and irritating to be in limp mode over brake pads swaps. I’ve been doing everything I can to not go the the dealer. Hope I’ve given some good info and if someone can help me solve the issue would be great.
Changing Rotors/pads
