[Camsdad13]

I’m stumped on this one. Been using Powerstop z26’s for years on multiple cars with no issues. The day after my 2019 Charger HC came in, I swapped pads for the Z26’s like I have in the past. This June I was driving from PA to FL. Hit rain in WV. I applied the brakes to slow for a toll booth and the car shook violently. First thing I thought was warped rotors. Rain let’s up and did some 80-0 stops and the brakes were smooth as silk, so no warped rotors. Suspension is fine, car has less than 10k on it. Tires and rims all fine. It only happens in the rain. It’s not like ABS kicking in. Vibration is in wheel and car and not the pedal. Brakes were bed properly and bed again.
Another thing I’m noticing is when I apply the brakes to start the car and start pulling out of the garage, it feels the right pad is stuck to the rotor slightly then releases. It only happens when I first pull out. It’s fine after that with no sticking.The car isn’t a daily driver. It stays in the garage for days at a time. No visible signs of rotor rust. Pads are carbon fiber and ceramic, I’d think they wouldn’t stick like that if there were rust. I checked the pistons and they aren’t sticking. I’ve eliminated all the issues I’ve felt would cause the problems. Anybody know what I’m missing? Any ideas on what to try next? Thanks in advance.

 

[Slowpoke387]

Stock wheels?

 

[Camsdad13]

Yes

 

[Blickie]

I’m stumped on this one. Been using Powerstop z26’s for years on multiple cars with no issues. The day after my 2019 Charger HC came in, I swapped pads for the Z26’s like I have in the past. This June I was driving from PA to FL. Hit rain in WV. I applied the brakes to slow for a toll booth and the car shook violently. First thing I thought was warped rotors. Rain let’s up and did some 80-0 stops and the brakes were smooth as silk, so no warped rotors. Suspension is fine, car has less than 10k on it. Tires and rims all fine. It only happens in the rain. It’s not like ABS kicking in. Vibration is in wheel and car and not the pedal. Brakes were bed properly and bed again.
Another thing I’m noticing is when I apply the brakes to start the car and start pulling out of the garage, it feels the right pad is stuck to the rotor slightly then releases. It only happens when I first pull out. It’s fine after that with no sticking.The car isn’t a daily driver. It stays in the garage for days at a time. No visible signs of rotor rust. Pads are carbon fiber and ceramic, I’d think they wouldn’t stick like that if there were rust. I checked the pistons and they aren’t sticking. I’ve eliminated all the issues I’ve felt would cause the problems. Anybody know what I’m missing? Any ideas on what to try next? Thanks in advance.

• Was your car new or used? If used, what history are you aware of??
• When you installed the Power Stops, did you use a good high-temp silicone brake lube on all pad contact points?
• Did you clean out the caliper channels where the pad sit and slide??
• Did you torque all lug nuts to 111 Ft Lbs with a proper torque wrench?
• Brake Pads run on the rotors... if the steering wheel shimmies on brake apply and hold, they could be warped. You need to dial indicate them to know with all lug nuts torqued to specs. And supposed "Brake Bedding" won't fix this either.
• Your 80 to 0 stops don't prove they are not warped AND that was unnecessarily hard on the pads and rotors. Doing these kind of stops can ruin pads for sure and maybe rotors as well.
• Front rotor pics??
• Many of these cars come from the factory with the "75 MPH Shimmy & Vibration" complaint and all wheels need a proper balance. You can Search on my name with keyword "balance" to see what fixes this issue.
• Have you had a proper 4-wheel alignment done?? Again, you can Search on my name with keyword "alignment" to see the proper way.
• Any signs of tire feathering on any tire??
• What is the color of the brake fluid in the Master Cylinder Reservoir??
• Here is something you have to check if you think a caliper is hanging for any reason. Every brake event has two halves; the apply and the release. Many people ASSUME these two separate events happen properly, and we know about ASSUME. Ideally, you would get the vehicle on jack stands and remove all wheels. Have someone help you in the driver's seat. Engine off, do one wheel at a time. Apply the brake pedal and check for apply; then release the brake and check for free rotor rotation immediately. The front wheels should turn by hand immediately on pedal release. You can try to turn the rears on release, but you may have to settle for making sure the brake pads are loose in the caliper channels after release, but you do have a M6 in neutral so the rears may turn easily.

 

[Camsdad13]

• Was your car new or used? If used, what history are you aware of??
• When you installed the Power Stops, did you use a good high-temp silicone brake lube on all pad contact points?
• Did you clean out the caliper channels where the pad sit and slide??
• Did you torque all lug nuts to 111 Ft Lbs with a proper torque wrench?
• Brake Pads run on the rotors... if the steering wheel shimmies on brake apply and hold, they could be warped. You need to dial indicate them to know with all lug nuts torqued to specs. And supposed "Brake Bedding" won't fix this either.
• Your 80 to 0 stops don't prove they are not warped AND that was unnecessarily hard on the pads and rotors. Doing these kind of stops can ruin pads for sure and maybe rotors as well.
• Front rotor pics??
• Many of these cars come from the factory with the "75 MPH Shimmy & Vibration" complaint and all wheels need a proper balance. You can Search on my name with keyword "balance" to see what fixes this issue.
• Have you had a proper 4-wheel alignment done?? Again, you can Search on my name with keyword "alignment" to see the proper way.
• Any signs of tire feathering on any tire??
• What is the color of the brake fluid in the Master Cylinder Reservoir??
• Here is something you have to check if you think a caliper is hanging for any reason. Every brake event has two halves; the apply and the release. Many people ASSUME these two separate events happen properly, and we know about ASSUME. Ideally, you would get the vehicle on jack stands and remove all wheels. Have someone help you in the driver's seat. Engine off, do one wheel at a time. Apply the brake pedal and check for apply; then release the brake and check for free rotor rotation immediately. The front wheels should turn by hand immediately on pedal release. You can try to turn the rears on release, but you may have to settle for making sure the brake pads are loose in the caliper channels after release, but you do have a M6 in neutral so the rears may turn easily.

Thanks for taking the time with the great questions and things to look for.

1. Car was new. Ordered and picked it up right off the truck.
2. Used the silicone that came with z26 pads on all contact points.
3. All Caliper Channels we cleaned. Car had around 100 miles when installed but I'm pretty anal about cleaning everything when I change them.
4. Lug nuts all torqued to 111ftlbs. I hand tighten in star pattern and torque from there in star pattern. I even go to the OCD extreme of ma
5. Steering wheel shimmied close to death wobble in a Jeep. No brake pedal vibration at all. Only happens when its raining and applying brakes from highway speeds.
6. I'll reply with Rotor pics shortly. No hot spots or anything out of the ordinary noticed.
7. Very familiar with the 75-85 shimmy issues with our cars. I've had multiple SRT's and Hellcats since 2007 and dealt with it before. Very experienced in road force and match mounting from dealing with those issues since 2007. I took off the OEM Pirelli's and had installed Michelin PS4's right after I took delivery just to avoid the 75-85 vibration. Car is smooth as glass through all speeds.
8. I have had a proper 4 wheel alignment done. Every SRT and Hellcat I've bought has been new, I let the suspension settle in a while then have it 4 wheel aligned. Familiar with alignment procedures too.
9. Zero signs of feathering and psi is 36 on all 4 tires.
10. I'll check master cylinder shortly for color. Good call on that.
11. Checked for Calipers hanging twice. The car is garage kept but I live in Fl with high humidity. After a few days the Rt Ft brake pads feel like they stick after starting and putting into gear. Kind of like metallic pads with rotor surface rust. No surface rust on the rotor and the pads are carbon fiber and ceramic. once I feel that little catch, there isn't a problem again until the next time it's driven after a few days.

The vibration only happens in the rain. Doesn't feel like ABS kicking in. Everything is perfect and smooth when its not raining. Again, I really appreciate your time helping. I'm stumped on this one.

 

[Blickie]

Thanks for taking the time with the great questions and things to look for.

1. Car was new. Ordered and picked it up right off the truck.
2. Used the silicone that came with z26 pads on all contact points.
3. All Caliper Channels we cleaned. Car had around 100 miles when installed but I'm pretty anal about cleaning everything when I change them.
4. Lug nuts all torqued to 111ftlbs. I hand tighten in star pattern and torque from there in star pattern. I even go to the OCD extreme of ma
5. Steering wheel shimmied close to death wobble in a Jeep. No brake pedal vibration at all. Only happens when its raining and applying brakes from highway speeds.
6. I'll reply with Rotor pics shortly. No hot spots or anything out of the ordinary noticed.
7. Very familiar with the 75-85 shimmy issues with our cars. I've had multiple SRT's and Hellcats since 2007 and dealt with it before. Very experienced in road force and match mounting from dealing with those issues since 2007. I took off the OEM Pirelli's and had installed Michelin PS4's right after I took delivery just to avoid the 75-85 vibration. Car is smooth as glass through all speeds.
8. I have had a proper 4 wheel alignment done. Every SRT and Hellcat I've bought has been new, I let the suspension settle in a while then have it 4 wheel aligned. Familiar with alignment procedures too.
9. Zero signs of feathering and psi is 36 on all 4 tires.
10. I'll check master cylinder shortly for color. Good call on that.
11. Checked for Calipers hanging twice. The car is garage kept but I live in Fl with high humidity. After a few days the Rt Ft brake pads feel like they stick after starting and putting into gear. Kind of like metallic pads with rotor surface rust. No surface rust on the rotor and the pads are carbon fiber and ceramic. once I feel that little catch, there isn't a problem again until the next time it's driven after a few days.

The vibration only happens in the rain. Doesn't feel like ABS kicking in. Everything is perfect and smooth when its not raining. Again, I really appreciate your time helping. I'm stumped on this one.

So, in the rain, the vibration occurs just driving and not braking?? If only during braking, then you have more checks.

These cars don't like an "In the Green" alignment. These cars need an EXACT Toe In of .10 Degrees each wheel.

Still think you need to check the "Dial Indicator on the Front Rotors" Box. You also check the torque on the rotor flange nuts... 78 In Lbs. If all of these are okay, then check rotor Parallelism. Measure the rotor thickness at 6 points around the circumference... should be identical at each point.

Tire pressure should be 32 cold.

You may need to check the Disc Pad Steel Plate Abutment Clearance in the Caliper Channel when cold. Should be .008 to .010 cold TOTAL.

 

[Camsdad13]

So, in the rain, the vibration occurs just driving and not braking?? If only during braking, then you have more checks.

These cars don't like an "In the Green" alignment. These cars need an EXACT Toe In of .10 Degrees each wheel.

Still think you need to check the "Dial Indicator on the Front Rotors" Box. You also check the torque on the rotor flange nuts... 78 In Lbs. If all of these are okay, then check rotor Parallelism. Measure the rotor thickness at 6 points around the circumference... should be identical at each point.

Tire pressure should be 32 cold.

You may need to check the Disc Pad Steel Plate Abutment Clearance in the Caliper Channel when cold. Should be .008 to .010 cold TOTAL.

Smooth in the rain until braking from highway speed. No rain, everything is smooth.

I'll have the alignment rechecked.

I'll check rotor hat flange nuts for proper torque.

Checked Rotor thickness at 4 points. They were at 34 mm. Car has 10K on it and not hard on the brakes.

Cold pressure is around 32. I checked it yesterday while driving and they were all at 36 hot.

I'm going to remove the pads this weekend, clean everything and replace high temp silicone.

Someone made the point of chatter from temperature change with rain. I'm going to make sure everything is clean and the rear of shims are coated well with Silicone. I'm going to coat the area between the pad and the shim too. The pads already had the shims in place when I installed them. I didn't put anything between the shim and pad, just back of shim.
I appreciate the help on this.

 

[Blickie]

Smooth in the rain until braking from highway speed. No rain, everything is smooth.

I'll have the alignment rechecked.

I'll check rotor hat flange nuts for proper torque.

Checked Rotor thickness at 4 points. They were at 34 mm. Car has 10K on it and not hard on the brakes.

Cold pressure is around 32. I checked it yesterday while driving and they were all at 36 hot.

I'm going to remove the pads this weekend, clean everything and replace high temp silicone.

Someone made the point of chatter from temperature change with rain. I'm going to make sure everything is clean and the rear of shims are coated well with Silicone. I'm going to coat the area between the pad and the shim too. The pads already had the shims in place when I installed them. I didn't put anything between the shim and pad, just back of shim.
I appreciate the help on this.

Don't use too much lubricant that it flows off the contact points; a thin film is enough. No need to put lubricant between the steel plate and the shim. That might help the shim to "walk" on the steel plate; just on top of the shim for the caliper piston contact points is all that's needed.

 

[baabootoo]

Ever got them really hot and then stopped so maybe they left some pad material on the rotor? Rotors don't usually "warp" anyway, it's uneven pad deposits left by over heated pads.

 

[Camsdad13]

Ever got them really hot and then stopped so maybe they left some pad material on the rotor? Rotors don't usually "warp" anyway, it's uneven pad deposits left by over heated pads.

I thought that at first. I’m going to just clean everything real good and see where it goes. A good thing is I took it out last night and had the right front stick went a depressed the pedal after starting. I drove it for a while and had no issues. I just went for a drive and got back. Today it didn’t stick after depressing the pedal.

 

[Slowpoke387]

My guess on the sticking part is maybe you put it away wet after rain or a wash? Water between the pad and rotor may or may not be a possible cause if still hot and still wet.

 

[vrwebster]

Another unnecessary Mod horror movie.

 

[butterscotch71]

Another unnecessary Mod horror movie.

And yet another unhelpful post from you

 

[Slowpoke387]

Another unnecessary Mod horror movie.

? You mean the Pstops?

 

[baabootoo]

"I know a guy"...............that had the same thing happen in dry though, so he gave me the Z26 pads. I haven't put them on yet, so I can't confirm or deny.

 

[Blickie]

"I know a guy"...............that had the same thing happen in dry though, so he gave me the Z26 pads. I haven't put them on yet, so I can't confirm or deny.

Unless there is some defect in the Friction Material, I doubt it's the pads. When he removes the pads this weekend, a good visual inspection of the pad surface is needed to see if there are any inconsistencies in the Friction Material. I'm running the same pads on both axles on the same '19 Charger HC & have ZERO issues. I love the PS Ceramics.

I still think it's a rotor issue slapping at the pads or a hanging caliper due to hanging pistons. My suggestion about making sure both halves of the brake event are actually occurring is critical. Each Caliper has to apply and fully release. After the Release, there should be a total of approximately .030 " (.015" per side) clearance between the pads and the rotor immediately and the rotor should spin freely with little to no contact with the pads. If you look at the center of the hardware anti rattle clips, there is a 30 Degree Ramp in the center to help move & hold the pads off of the rotors after pedal release, which is also important.

If you have the original Brembo Pads, you could reinstall as a test.

 

[Blkout]

? You mean the Pstops?

Yes, he doesn't believe in any mods so everytime he can find a chance to inject his .02 about not modding these cars, he does.

 

[Slowpoke387]

Yes, he doesn't believe in any mods so everytime he can find a chance to inject his .02 about not modding these cars, he does.

PStops are hardly a mod imo. That's kind of a reach tbh.

 

[S8ER01Z]

Do you have the “rain brake support” feature? My understanding is that when the wipers are on the brakes are cleaning water off the rotor at intervals. Maybe that is somehow not playing nicely with the pads?

 

[baabootoo]

I agree wholeheartedly. It's like all the ideas on the "wheel clicking" thing.............