Brake Rotor Problems

[JimD]

....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.

Since the advent of four wheel ABS, caliper sequence makes no difference in time or convenience.

Each caliper is plumbed individually to the ABS module. The only "shared" plumbing is between the master cylinder and the ABS module.

[KHE]

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

The brake fluid will pick up moisture but it is at a very slow rate. I think due to the slow rate of moisture absorbtion, the 10 year/100,000 mile flush works. Some drivers get over 100,000 miles on a set of brakes if they do a lot of highway driving.

It's not like PAG oil used in the air conditioning systems that will absorb moisture so fast that you need to not leave the A/C system open for any length of time. Just some of my thoughts.

[Texas Jim]

My 2006 DTS has a little over 107,000 miles on it and it still has the original pads and rotors.

It SOMETIMES has a pulsating feeling like the front rotors are warped.

I don't believe it is a rotor, because it don't do it all the time... just "MOST" of the time.

Sometimes it is really bad and the more you use the brakes, the worse it gets.

Sometimes you can barely feel it...and occasionally it is just as smooth as silk.

I just found this out a few days ago....

2006 and 2007 DTS and Buick Lucernes with the Northstar have a known problem with brakes.

There is a TSB on it, but I do not have the TSB number.

On my model car and on Norm B's car, which is similar to mine...

There is a new part number for the brake pads...

The original part number is....19165980

The new part number is....25837407

The new pads are supposed to cure the pulsating / vibration problem that these cars seem to be afflicted with.

I will be putting these on my car in a couple of weeks, along with brand new front rotors.

[Ranger]

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.

I remember that and that is the schedule I follow as well.

It SOMETIMES has a pulsating feeling like the front rotors are warped.

Check this out if you haven't seen it before Jim.

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

[Texas Jim]

It SOMETIMES has a pulsating feeling like the front rotors are warped.

Check this out if you haven't seen it before Jim.

http://www.stoptech....brakedisk.shtml

Thanks....I read it.

That's exactly what I think has happened to mine.

That is why I am going to put the new type pads on it, along with new rotors.

Maybe the pulsating will finally go away...

[JohnnyG]

My 2006 DTS has a little over 107,000 miles on it and it still has the original pads and rotors.

It SOMETIMES has a pulsating feeling like the front rotors are warped.

I don't believe it is a rotor, because it don't do it all the time... just "MOST" of the time.

Sometimes it is really bad and the more you use the brakes, the worse it gets.

Sometimes you can barely feel it...and occasionally it is just as smooth as silk.

I just found this out a few days ago....

2006 and 2007 DTS and Buick Lucernes with the Northstar have a known problem with brakes.

I've got some bad news for GM, it affects the 2008 DTS as well. Mine does the exact same thing, the hotter they get (as in descending a long steep grade, braking periodically) the worse the pulsation is. I just live with it and will switch to the new pads someday.

[BodybyFisher]

I am surprised to hear this, why has this problem not been eliminated?

What is causing this?, brake pad compound?

[Texas Jim]

My 2006 DTS has a little over 107,000 miles on it and it still has the original pads and rotors.

It SOMETIMES has a pulsating feeling like the front rotors are warped.

I don't believe it is a rotor, because it don't do it all the time... just "MOST" of the time.

Sometimes it is really bad and the more you use the brakes, the worse it gets.

Sometimes you can barely feel it...and occasionally it is just as smooth as silk.

I just found this out a few days ago....

2006 and 2007 DTS and Buick Lucernes with the Northstar have a known problem with brakes.

I've got some bad news for GM, it affects the 2008 DTS as well. Mine does the exact same thing, the hotter they get (as in descending a long steep grade, braking periodically) the worse the pulsation is. I just live with it and will switch to the new pads someday.

I have been living with it since I bought the car new...

It now has a little over 107,000 miles on it, so it is about time for new brakes anyway.

I will put the new recommended ones on it and see if it fixes the problem.

I sure hope so... 'cause if it don't... they will get replaced pretty quick with aftermarket pads...

I have had all of that pulsating brakes stuff I am gonna put up with.

One way or another... "IT WILL BE FIXED"... :)

[Ranger]

Both my '02 SLS and this '03 DHS had rotors replaced or resurfaced under warranty at least once due to pulsation.

[JohnnyG]

I am surprised to hear this, why has this problem not been eliminated?

What is causing this?, brake pad compound?

Maybe because most of us choose to live with the problem, rather than deal with the "run around" at the dealership. First of all, the problem is hard to duplicate, it only happens on high speed runs and gets worse as the rotors heat, which is not that unusual. Keep in mind too that I've now heard of two possible causes for this, the brake pad material, and the "new" style tie rod(?) end. These are offered in addition to the issues most of us already know about such as the "uneven distribution of pad material (regardless of material type)", as well as general abuse, warping the rotors, etc.

So it's a complicated problem with more that one single solution. I personally see the potential for SEVERAL trips to the service department on this single issue alone. It is also unlikely that any replacement rotors would be specifically designed to prevent this, so you end up with more of the same for your time and effort.

It's still a nice car, and most of the time tooling around town this problem never presents itself.

[KHE]

I had to replace a rear rotor on my '05 Deville about a year ago. The brakes became horribly rough - almost like metal on metal ccntact. The rotor was delaminating - there were chunks of metal the size of a quarter that were gone and there was a shallow "crater" left on the rotor which was causing the issue.

I replaced the rotor - the parts store said he could turn the rotor and it would be fine for awhile but the delamination would happen again. I have never heard of this before - it must be due to poor metallurgy in the rotor.

[JohnnyG]

I had to replace a rear rotor on my '05 Deville about a year ago. The brakes became horribly rough - almost like metal on metal ccntact. The rotor was delaminating - there were chunks of metal the size of a quarter that were gone and there was a shallow "crater" left on the rotor which was causing the issue.

I know "delamination" sounds more exiting, but did those holes happen to be rusty inside? The reason that I ask is that I've seen this before, about 20 years ago. On a friends (wifes) car, driven daily to work and then parked in a warm garage overnight. Somehow road salt entered the recesses for the rivet holes that held the rear brake pads to the backing plates and didn't dry out. After a long weekend, holes were rusted deeply into the rear rotor surfaces. Apparently the salty liquid promoted galvanic corrosion of the rotor surfaces in a very short amount of time. It seems to me that Michigan might be a place where this could happen. To be fair, the holes I saw were more the size of a dime rather than a quarter, but it did happen in a short time period. The pads and backing plates didn't fair too well either!

[KHE]

I know "delamination" sounds more exiting, but did those holes happen to be rusty inside? The reason that I ask is that I've seen this before, about 20 years ago. On a friends (wifes) car, driven daily to work and then parked in a warm garage overnight. Somehow road salt entered the recesses for the rivet holes that held the rear brake pads to the backing plates and didn't dry out. After a long weekend, holes were rusted deeply into the rear rotor surfaces. Apparently the salty liquid promoted galvanic corrosion of the rotor surfaces in a very short amount of time. It seems to me that Michigan might be a place where this could happen. To be fair, the holes I saw were more the size of a dime rather than a quarter, but it did happen in a short time period. The pads and backing plates didn't fair too well either!

I did not recall any rust in the areas that were exposed due to the absence of material. I have never had this on any of my cars before.

[BodybyFisher]

I had heard that rotors from china had voids within them and I was told to avoid them, I dont know if that has changed or not

[Ranger]

My '97 had areas of rust on the rear rotors that caused a pulsating sound. Hard to believe that they would rust like that. You'd think the first brake application would clean them. Just ordered a set of pads and rotors this morning for my '03. This time the rust is in the center of the rear pad wear area in a ring. They are groaning pretty bad. Bad part is I'm sure the pads are probably only 50% gone.

[JohnnyG]

This all seems quite odd when I think about it. We worry about voids and holes, but go out and purchase drilled rotors. The groaning I can understand well enough, particulaly during low speed brake application. Ultimately the holes/voids may not be that important on rear discs.

I HAVE lost complete sections of rear brake pad material once, which I thought was significant, and completely due to rust on my old winter vehicle, a 1998 Grand Cherokee. I tried to report that to the NTSB, but they said it wasn't a big deal.

Maybe none of these rear brakes are doing the 30% of the braking that they are supposed to be doing. This brings us back full circle to the issue of bleeding the brakes or changing fluid. Or, they just last so long that they will be affected by rust much more than we think. In fact it may be better, on a winter car, to change rear brakes on a time schedule than just checking them for wear. Maybe like 5 or 6 years max.

We all need to be more careful and observent of our rear brake pads/rotors, especially if we live in areas of high road salt exposure.

[KHE]

I had heard that rotors from china had voids within them and I was told to avoid them, I dont know if that has changed or not

In my case, the rotor in question was the OEM rotor that was on the car. Apparently, the Chevy/GMC trucks in the early 2000s had bad rotors on them also.

This all seems quite odd when I think about it. We worry about voids and holes, but go out and purchase drilled rotors. The groaning I can understand well enough, particulaly during low speed brake application. Ultimately the holes/voids may not be that important on rear discs.

I HAVE lost complete sections of rear brake pad material once, which I thought was significant, and completely due to rust on my old winter vehicle, a 1998 Grand Cherokee. I tried to report that to the NTSB, but they said it wasn't a big deal.

Maybe none of these rear brakes are doing the 30% of the braking that they are supposed to be doing. This brings us back full circle to the issue of bleeding the brakes or changing fluid. Or, they just last so long that they will be affected by rust much more than we think. In fact it may be better, on a winter car, to change rear brakes on a time schedule than just checking them for wear. Maybe like 5 or 6 years max.

We all need to be more careful and observent of our rear brake pads/rotors, especially if we live in areas of high road salt exposure.

In my case, the rear brakes were working properly - they were bright and shiny where the pad interfaced.

I thought the same thing about the cross drilled rotors but I think the roughness comes from the non-uniform surface created when the rotor flakes away chunks.

[JimD]

Severely off topic and a bit of a war story. I will try to be brief!

Several years ago, my Michigan resident brother-in-law mentioned that his Jeep (Wagoneer, I think) was very "noisy" when braking. Understand that he is an educated man that has no feel for physics or mechanical applications; gas and go is his philosophy.

We quickly determined that his RF rotor was in two pieces; the rotor braking surface was seperated from the remainder of the rotor. Rust/corrosion/oxidation or whatever.

That was an eye-opener. Never before and not since have I seen the same damage.

[JohnnyG]

You know, I was just re-reading this thread, and it's really funny in a way. A gentleman by the name of Rusty posted originally, but has never replied to a single post by any of us. I find that quite strange that we, and I'm just as guilty, took off on the subject from the get go with no further input from the guy with the problem.

Finally, after re-reading the original post again, I have no idea what Rusty's real problem is. Is the "vibration issue" happening while driving down the road (tire balance) or when applying the brakes? One very intelligent poster once said that the amount of imbalance in a rotor, that would be needed to feel it at highway speed (without applying the brakes) would be nearly impossible to achieve.

Reminds me of another poster a few years back in a way.