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Brake Rotor Problems


Rusty

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I just purchased and installed new Brembo rotors and ceramic pads on the front and braking action is much improved. However, the dreaded vibration is back which is kind of disheartening. I called the Caddy dealer (who didn't do the work) and he suggested the rotors could be out of balance and I might have to return them to the vendor. This is major aggravation at this point. I called the local Buick dealer and he informed me of a GM directive that all rotor changes be checked for runout, and shim kits used as required. Acceptable range is .001-.002 inches, (yes that's 1-2 thousands). Very intesting that the Caddy dealer was behind the curve again, especially given the history of problems in this area. I'll be schedling a trip to the Buick dealer to check the rotors. Hopefully this will return the smooth ride that I'm missing.

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I have been having the same problem. I"m on my third set of rotors in less than a year. They've been replacing them under warranty, but I have moved a thousand miles away. That vibration is really aggravating!

Think I"m gonna go to ceramic pads and cross drilled rotors.

Tim

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Are those Brembo rotors drilled? If your rear brakes are not doing their share of work, you will overheat and 'warp' your fronts, its the overheating that causes the problem. I think you need to look at the rear brakes carefully and ensure they are doing their SHARE of the work and that they are BLED and ADJUSTED properly. The rear brakes on these cars are not easy to change and adjusting them requires that the parking brake adjustment be considered and the adjustment procedure is tricky. In addition with the ABS system, its difficult to properly bleed the brakes, if you have air in the rear system the rear will not GRAB and you WILL overheat the front rotors....I have been fooled many times by this! Mike

Read this if you have not already:

http://www.stoptech.com/whitepapers/warped_rotors_myth.htm

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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  • 7 years later...

I just purchased and installed new Brembo rotors and ceramic pads on the front and braking action is much improved. However, the dreaded vibration is back which is kind of disheartening. I called the Caddy dealer (who didn't do the work) and he suggested the rotors could be out of balance and I might have to return them to the vendor. This is major aggravation at this point. I called the local Buick dealer and he informed me of a GM directive that all rotor changes be checked for runout, and shim kits used as required. Acceptable range is .001-.002 inches, (yes that's 1-2 thousands). Very intesting that the Caddy dealer was behind the curve again, especially given the history of problems in this area. I'll be schedling a trip to the Buick dealer to check the rotors. Hopefully this will return the smooth ride that I'm missing.

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I have found that a majority of brake warpage problems stem from incorrect torqueing of the wheels

(especially aluminum wheels). I torque the wheels in three steps with a torque wrench. I have several torque wrenches that I use to insure accuracy. I found that when I was in a stressfull situation, ie when under a racing deadline, that I tended to "gorilla" the bolts. The torque wrench kept me grounded.

Nes74

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I have this problem with almost every vehicle, and I am a stickler about properly torquing the wheels. I give up. I get about 6 months before the vibration starts. I have seen many vehicles have to have rotors changed before the first set of pads. Example our 98 ford contour, had brand new brakes(everything including hubs) installed about a year ago. 3500 miles and one heck of a pulsation. Removed wheels, brake pads evenly but barely worn. rotors were terrible.

It doesnt even seem to matter what brand you get or how much you spend. And honestly I have the exact same issues with GM and AC Delco parts. Just terrible

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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I believe that this is due to improper procedures when replacing the brakes.

The front brakes account for a major percentage of stopping power, probably 70%, with the rear only taking up 30%.

So the front brakes wear out faster and are replaced more often. The rear brakes on most cars are for the most part ignored.

So lets say that instead of 70%, the fronts are now taking 80% of the load because the rears are slacking, that causes heat and heat is the brakes worst enemy, once the brakes overheat, there is a transfer of brake material from the pad to the rotor causing a thickness variation and you have pulsing and hammering. Most of the time the rotors are not 'warped', there has been brake material transfer to the rotor causing rotor thickness variation and an uneven surface that is 'grabby' in spots. I am not saying that a rotor can not be out of square, bent or warped, but it helps if they are torqued correctly, and trued up at each brake job. I recently had a rotor that did not true up with a machining having been done and only a new rotor solved the problem.

I believe that for the brake system to operate correctly the following must be done:

1) when a brake job is done all 4 wheels must be bled, if the front is bled and the rear is not bled of all air, the rear will not apply proper clamping force and slack and overheat the front. Many DIYer's never bleed the brake system as they are intimidated by the bleeder screws breaking off, but the system must be bled front and rear at every brake job.

2) when the front brakes are done, all 4 wheels must be disassembled and the sliders cleaned and proper slider grease used, all rust must be removed under the rubber slider boots

3) when the brakes are hot, avoid the parking brake, and avoid holding the brake at stop lights as much as possible, even putting the car in neutral

4) flush the system of brake fluid at least every 2 years or when a brake job is done, it absorbs moisture and negatively impacts braking when hot

5) the rotors must be either replaced or resurfaced with a non directional finish by a machine shop for the new pads to seat properly and to 'square them up' at each brake job.

6) the brake hardware should be replaced (all rubber, clips) at least every other brake job. If a slider is corroded replace it. Buy the hardware kits

7) use a torque wrench as noted above and make sure the mating surfaces are clean of rust and scale

Keep in mind that the rear rotors are not vented, non vented rotors run hotter. Notice how many times your see your rear rotors black from heat.

Heat must be kept to a minimum

We DIYer's do the job to keep the cost to a minimum, but short cutting or doing the job cheaply only leads to trouble

Why bleed brakes?

  • Fresh brake fluid has a significantly higher boiling point than old fluid, allowing harder braking without fade. This is because brake fluid is hygroscopic and readily absorbs moisture. The more moisture in the fluid, the lower the boiling point.
  • That same moisture promotes corrosion. Frequent bleeding with fresh fluid allows brake components to last longer. A well maintained brake system can help you avoid ever having to replace calipers, master cylinder or an expensive ABS control unit.
  • The bleeding process, done properly, removes air bubbles from the hydraulic system, resulting in firmer brake pedal feel and more linear, responsive braking performance. Too much air in the system can be dangerous and result in the pedal sinking to the floor. Air is compressible, brake fluid is not.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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This is probably going to sound silly but I had the vibration problem until a replaced my ACDelco front brakes with Wagner ThermoQuiet Brake Pads. After driving for a week or so I noticed the vibration when braking was going away. Now I don't notice any vibration when braking. Also, the front rotors smoothed out with the Wagner brakes. I know it sounds ridiculous but it seems the Wagner brakes cured the vibration problem. I bought new rotors figuring I had to replace them to get rid of the annoying vibration problem. Now they're sitting in my closet because I don't feel a need to replace them. The only complaint I have with the Wagner brakes is that they produce a lot of brake dust.

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This is probably going to sound silly but I had the vibration problem until a replaced my ACDelco front brakes with Wagner ThermoQuiet Brake Pads. After driving for a week or so I noticed the vibration when braking was going away. Now I don't notice any vibration when braking. Also, the front rotors smoothed out with the Wagner brakes. I know it sounds ridiculous but it seems the Wagner brakes cured the vibration problem.

Not at all unusual. Vibration while braking is commonly (frequently) the result of uneven brake pad material distribution on the surfaces of the rotor.

The easiest and least expensive to scrub the rotor surfaces "clean" is to make 10 hard stops from 45 MPH which will put some serious heat in the pads/rotors and smooth the microscopic layer of pad material.

Rotors on street-driven cars rarely warp. But the uneven pad material distribution can "feel like" the rotor is warped.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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Ditto to JimD's comments

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Bodybyfisher

I don't understand your advocating brake bleeding if the system isn't opened up from changing calipers, a brake line or anything that opens the system. I've never bled just changing pads & rotors or back in the 60's shoes & drums.

Norm

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Bodybyfisher

I don't understand your advocating brake bleeding if the system isn't opened up....

Run this concept through your logic filters.

As the brake pads wear, the fluid level in the master cylinder will be reduced (How could the master cylinder fluid level not be reduced?). Since the master cylinder fluid level is now lower than it was when all new components were installed, what replaced the brake fluid in the master cylinder?

Ambient air. Ambient air contains moisture. And moisture + DOT 3 brake fluid is not a happy marriage.

Automakers have tried to minimize the affect by using rubber master cylinder cover gaskets that include expandable sections to occupy the vacant fluid space. And that works, sort of.

IF you plan to drive the car for ten+ years, completely replacing all the brake fluid every 2 to 3 years years (as well as whenever the brake system is "opened up") is very inexpensive insurance against spongy brake pedals and corroded pistons.

Depending on your tolerance level for reading "Internet" information, parts of this thread might be worth thinking about.

http://caddyinfo.ipbhost.com/index.php?showtopic=9823

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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Thanks Jim

Norm, see under the paragraph WHY BLEED BRAKES at this link. Norm, EVERY time I bleed my brakes I get AIR BUBBLES out of the system, its not as sealed as you think it is

http://www.stoptech.com/tech_info/wp_howto_bleedbrakes.shtml

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I understand how brake fluid works. I do bleed my brakes,[change the fluid] not after brake work but every 2-3 years ever since I had front calipers seize on a R.V. that sat 6 months of the year. My other ride is a 93 Yukon I've had since new. The master cylinder & front calipers are still original. I credit their longevity to changing the fluid, but I think they're due to be changed.

I don't know about this DTS. The GM maint. record shows the fronts done 3 times, rears twice. Front rotors were turned at 8000 mi. I think the original owner was hard on brakes. The car had 54,000 mi. when I got it in early July.

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I understand how brake fluid works. I do bleed my brakes,[change the fluid] not after brake work but every 2-3 years ever since I had front calipers seize on a R.V. that sat 6 months of the year. My other ride is a 93 Yukon I've had since new. The master cylinder & front calipers are still original. I credit their longevity to changing the fluid, but I think they're due to be changed.

I don't know about this DTS. The GM maint. record shows the fronts done 3 times, rears twice. Front rotors were turned at 8000 mi. I think the original owner was hard on brakes. The car had 54,000 mi. when I got it in early July.

You are sounding a little indignant, I was NOT instructing you on HOW brake fluid works. I change my pads every 40,000 miles or so, which is about every 3 years, bleeding and changing the fluid at that time is a good practice.

You said this: I don't understand your advocating brake bleeding if the system isn't opened up from changing calipers, a brake line or anything that opens the system

I gave you the link to see this and why the system needs bleeding, all 4 brakes even if only the front is done, so that the REAR picks up its share of the load, we are talking about brake shutter here and the reasons why, as fluid ages its boiling point drops, creating air from boiling the fluid. My point was that the rears are overlooked and they should be refurbished when the front is done, including bleeding and changing the fluid, because if there is AIR in the rear, the rear will NOT pick up its fair share of the braking work:

This came from the above StopTech link:

We bleed the brakes to release air that sometimes becomes trapped within the lines. Technically, "air" only enters the lines if there is a compromise of the system's sealing (as when flex lines are removed or replaced), because when fluid boils, it will instead create "fluid vapor." Vapor in the brake fluid, like air, will create an efficiency loss in the braking system. However, for the sake of simplicity we use the term "air" throughout this article to describe both air and fluid vapor.

When air (or vapor) becomes present within the lines, it creates inefficiencies within the system because, unlike liquid, air can be compressed

So how does air enter the lines in the first place? Sometimes, it can be the result of a service procedure or an upgrade – such as replacing the stock flex lines with stainless steel braided lines. But often it is the result of high temperatures that cause brake fluid components to boil, thus releasing gasses from the boiling fluid into the brake hydraulic system.

So even though the fluid itself is unlikely to boil (most glycol-based DOT3 fluids have a "dry boiling point" around 400 degrees Fahrenheit,) the water that it absorbs over time tends to boil easily (at 212 degrees Fahrenheit.)

***********************************************

And that is the reason why I say its important to bleed all 4 brakes at each brake job even if just the FRONT is done. As I said, every time I bleed my brakes, I get air bubbles! As JimD has recommended, a full flush should be done every 2 years to replenish the brake fluid by getting rid of any absorbed moisture and to RAISE its BOILING POINT, to allow ALL 4 brakes to work at FULL EFFICIENCY so as NOT to put extra STRESS which equates to HEAT on the front ROTORS which contributes to material transfer and the resultant brake shudder...

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Change the brake fluid on a vehicle that has not been changed in a few years & After seeing the fluid, you'll know whey it should be changed. Rust, and black goo will be all in the fluid.

You can say that again, and the smell is unforgettable. amazing it works at all. All it is good for by then is eating paint

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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The guru used to say to change the brake fluid every 10 years or 100,000 miles. That's the schedule I have followed and I have not had any brake issues with my cars.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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The guru used to say to change the brake fluid every 10 years or 100,000 miles. That's the schedule I have followed and I have not had any brake issues with my cars.

You do bleed your brakes when you service them however, no?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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You do bleed your brakes when you service them however, no?

Other than the 10 year/100,000 mile interval, the only time I bleed brakes if I have the system opened up. The most recent times were: Fleetwood - the rear wheel cylinders were starting to leak so I replaced them.

The other time was on the Seville SLS I used to own. The rear caliper mounting bolt broke and I needed to use the torch to remove the broken piece of the bolt. I replaced the caliper dust boot and piston o-ring so I needed to bleed that side after the repair was complete.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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You do bleed your brakes when you service them however, no?

Other than the 10 year/100,000 mile interval, the only time I bleed brakes if I have the system opened up. The most recent times were: Fleetwood - the rear wheel cylinders were starting to leak so I replaced them.

The other time was on the Seville SLS I used to own. The rear caliper mounting bolt broke and I needed to use the torch to remove the broken piece of the bolt. I replaced the caliper dust boot and piston o-ring so I needed to bleed that side after the repair was complete.

That is interesting, its good that you don't have any issues and I believe you 100% as I have full confidence in you and your mechanical expertise, but it seems to run counter to research I have done that shows that brake fluid gradually loses its resistance to boiling as it pickes up moisture... Interesting to see another perspective

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I generally do not bleed brakes when I replace pads. Only if there is a sign of air in the system, which usually means I replaced a rubber hose or something else. Though I must admit that I have been wanting to take the time to flush the system and replace fluid with synthetic. With 195,000 miles on my STS, I'm thinking it's time to flush the system even though at this point braking is good. Now that the weather is getting cooler I'll take the time to get it done. From what I read, the system should be flushed starting with the caliper furthest away from the brake master cylinder, which is usually the right rear, then left rear, then right front, and lastly, left front. I don't believe there is a bleeder screw on the master cylinder.

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