Pulsating Brakes [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

: Pulsating Brakes


TheWETZ
06-30-2006, 09:17 AM
Hello all,
I have a problem with my brakes pulsating when stopping. I thought it was due to warpped rotors, but I had them turned and the Trailblazer still has the problem :mad:. The pulsating occures once the Trailblazer is between 20 mph - 0 mph. If I am at a high rate of speed and push on the brakes, I cannot feel the brakes pulse.

What could this be :confused:.
My next thought on this problem would be the Tie rods. But the vehicle is a 2002 with 36,000 miles on the clock.
Any help will be appriciated :D .

LOWRIT00
06-30-2006, 09:53 AM
Hello all,
I have a problem with my brakes pulsating when stopping. I thought it was due to warpped rotors, but I had them turned and the Trailblazer still has the problem :mad:. The pulsating occures once the Trailblazer is between 20 mph - 0 mph. If I am at a high rate of speed and push on the brakes, I cannot feel the brakes pulse.

What could this be :confused:.
My next thought on this problem would be the Tie rods. But the vehicle is a 2002 with 36,000 miles on the clock.
Any help will be appriciated :D .

:undecided Well it could be from the caliper it self, on my '04 envoy I have a dual piston caliper up front, this should be the same for your too, sometimes one or the other piston can "freeze" or be slower then its partner, in this case you can feel the pulsating at slower speeds, or some call it chatering. in order to fix this problem replace caliper, before doing that test it..... take off tire, take off caliper and pads, have some one push the brake pedal and see if both pistons on the caliper come out even if not replace caliper. :yes: let me know if this works for you.:thumbsup:

thats my :m2:

rlouisa
06-30-2006, 09:57 AM
Did they replace the brake pads when they turned the rotors? If they didn't do that, you can also get a chatter. Just thinking out loud here.

Ryan

TheWETZ
06-30-2006, 01:12 PM
Thanks for the quick responce.
I do have the dual piston calipers on the Trailblazer. I didn't think that could be the problem. I will try and test them sometime next week and post my results.
As for the brakes. I did the work myself. I don't like other people messing with my vehicles. So I pulled the rotors off and took them to Checker, and had them turn the rotors. But I will also check the brakes to see if they are the problem, and I will post the results of that also. :D

gmcman
07-03-2006, 10:05 AM
Does the wheel shake back and forth with the pulsating or does your rumpshaker move back and forth on the seat? The rump shake would be your rear rotors.

TheWETZ
07-05-2006, 09:37 AM
I haven't noticed my "Rumpshaker" moving back and forth. But I feel the pulsing mostly in the brake pedal.

Ruffdog
07-05-2006, 10:11 AM
Replace the rotors, they are junk!!!!! you cannot cut a warped rotor , it will pulsate the minute it gets hot.
I have had the dealer replace my rotors at 8,000,14,000 and again at 35,000. the junk steel they are using is a pain in the ass.
I have just replaced the rotors again at 40,000 and I bought a good steel rotor from Murrays autoparts with a 5 yr warranty on the rotor,I'm gonna see how these do.
I am not a heavy footed driver, I do all my driving in the city.
My wife has an 02 impalla and I just replaced her rear rotors at 25,000mi,they were rotted on the backside and were pulsating also.
This steel they are using is crap,but due to the costs of slotted rotors I will continue using replacement ones from the aftermarket, because I can buy a rotor for 25 bucks compared to 90 a piece for the slotted ones.
I do all my own work also , I was a gm mechanic for 10 yrs before I changed professions, it usually only takes me about an hour to do a brake job and that includes sucking out old fluid from the master, and bleeding the brakes on all 4 wheels each and every time.
If you want to pay 2500 bucks for Baer go for it but I can't see paying that for brakes that are gonna get replaced every 30,000 mile, when I can do a 2 wheel set for 100 bucks.

Excell
07-05-2006, 11:18 AM
Replace the rotors, they are junk!!!!! you cannot cut a warped rotor , it will pulsate the minute it gets hot.


Yep. Turning warped rotors will do no good, the rotors need replaced.

Boilermaker-744
07-05-2006, 01:17 PM
Keep us informed on the situation and what the ultimate culprit was.

TheWETZ
07-07-2006, 02:31 PM
I haven't had much time to look into the problem again.
But I am now considering new rotors.
Where is the best/cheapest place to buy new rotors?

ieatglue
07-07-2006, 02:42 PM
Are they big pulses or really small ones. When i brake, i feel a really small vibration feeling, sorta like the ABS or something :undecided

gmcman
07-07-2006, 02:55 PM
Whaddayerrr tires look like in the front....are they cupped or feathered? Sometimes badly feathered tires will give a washboard feel when slowing down. If your steering wheel stays still when braking I doubt it is your rotors. There is a TSB on the intermediate (?) steering shaft which may be the culprit but that's a longshot.

DCMAN-1
04-21-2011, 08:58 PM
I feel the pulsating @ slow speeds, happens right after rotors are turned, or replaced.

Could the ABS computer be the source of this problem?

tisoy3
04-29-2011, 10:36 AM
I'm having the same issue. Pulsating at slow speeds. Will definately be checking rotors and pads..

wilts42
05-09-2011, 11:22 AM
bump for a solution, as my 2004 is doing the exact same thing. I know its not from heat because my truck will do it 20 yards down the road.

awer25
05-09-2011, 05:59 PM
Mine too. Strange that there's 4 of us in the last month with this problem...

I haven't gotten a chance to check the rotors, but I did rotate the tires last week and all brake pads were wearing evenly. The dual-piston issue sounds like it could be the problem, but I really don't feel like replacing the caliper!

JerryIrons
05-09-2011, 07:21 PM
If I had pulsating brakes like that the first thing I would do would be put brand new rotors and pads on. I am under the impression that you can have rotors turned, but they will be thinner than before and even more prone to warping from braking heat.

As to which rotors to buy, I have no clue. I've bought the most expensive rotors they sell to the cheapest I could buy throughout my life and it all seems like it's a crapshoot.

kustomiser
05-09-2011, 09:52 PM
i am new here and i am having sorta the same problem but mine seem like the antilock brake pump is working even with light pressure on the pedal,also when braking from say 45 mph when the trailblazer gets under say 15 mph the pedal pulses and feels to me like the abs engauges till stops. does not do it every time but is different getting more noticeable

Outlaw
05-10-2011, 01:13 AM
Our 03 did the same thing less then 2yrs ago and is doing it again. We got rid of it the first time by replacing the rear rotors. Didn't touch the fronts, now it's doing it again. We are going to replace all the way around this time with drilled and slotted with ceramic pads. Hopefully it will last more then 2yrs.

wilts42
05-10-2011, 09:03 AM
thanks outlaw,

To the person concerning turning the rotors, if they are newer or have never been turned there is absolutly no reason not to turn them a couple times before buying new. When turing rotors that have alittle worp there is not very much material taken off

guano2
05-10-2011, 02:59 PM
Let me put the most informative :m2: in here and I will say best Mod money I've spent in 37 years of driving [Besides that first; 68BuickGS 4spd. (BB Crane Cam) when I was a Teenager:eek::dielaugh:] ;

.[Brakemotive 76; on Ebay drilled & slotted rotors & pads "Free Shipping"]

My 02 ABS system has been overclamping onto the fronts (for lack of a better description) Warping brand new rotors forever (in 6 months) it did not destroy these rotors.
Also; Since working on the front & inadvertantly getting too much antisieze in a front hub thereby throwing a code & shutting the system down (which cured the warping issue for now (couldn't even turn the wheels before that)
Yes I Know I have to figure this out, but it's working OLD SCHOOL GREAT for now....SO.....
Go to E Bay, Get Them, You won't Regret it.:tiphat
They work great for those 200 MPH trips to the Grocery store too.:yes::D
more important (rustbelt) The plating.:thumbsup:

02 T-Blaze
05-13-2011, 05:20 PM
I'm having the same issue with the slower speed brake vibes. I've warped one set of rotors then changed out rotors/pads/calipers and now it's back again. I wonder if it's a crappy design (whaaat? GM?) and the brakes generate too much heat and then we warp the rotors. I'm going to try replacing with drilled/slotted rotors and see if that'll last a few more years.

Doc Brown
05-16-2011, 12:48 PM
True rotor warpage is actually quite rare. More than likely the pulsating is caused by pad material that has hardened onto the rotor. That's caused by improper bedding procedure. What happens is that holding the brake at a stop for a period of time after getting the brakes hot forces material to burn onto the rotor. As the pads age and get hard, they skip off of the hardened pad deposits and grab the "good" parts of the rotor. Causing the pulsating. Even putting new pads on don't always get rid of the problem entirely. Instead of cutting the rotors hit the brakes FIRMLY a few seconds later (when safe to do so) than you normally would. Do that for a couple of weeks, the pad material will start to wear off. Then change the pads.

When putting on new pads, bedding them properly will prevent a lot of pulsating and what many people call "warped" rotors. Properly bedding your new brake pads (http://www.zeckhausen.com/bedding_in_brakes.htm).

mnypitEXT
05-21-2011, 03:35 PM
This seems to be a common problem. On our 05 I have pulsation in the rear of mine as well. When we bought it, they were supposed to have fixed it with new rotors and pads, and that was at like 36k. They replaced them but It never stopped pulsating, but prying it out of my wife's hands to work on it is tough. So we lived with it for a long time. Recently I replaced the rear rotors and pads, and used drilled and slotted. Still the same problem. So about 2 weeks ago, I had the stock rotors turned, and bought another set of pads. Still the same problem. So now we have 3 differant sets of pads and 2 sets of rotors replaced and ultimately turned with the same issue.

Anybody got a real solution for this??? Someone mentioned maybe it is an ABS issue, causing the rears to think they are locking thereby pulsing?? Just a thought.

awer25
05-22-2011, 12:38 PM
This seems to be a common problem. On our 05 I have pulsation in the rear of mine as well. When we bought it, they were supposed to have fixed it with new rotors and pads, and that was at like 36k. They replaced them but It never stopped pulsating, but prying it out of my wife's hands to work on it is tough. So we lived with it for a long time. Recently I replaced the rear rotors and pads, and used drilled and slotted. Still the same problem. So about 2 weeks ago, I had the stock rotors turned, and bought another set of pads. Still the same problem. So now we have 3 differant sets of pads and 2 sets of rotors replaced and ultimately turned with the same issue.

Anybody got a real solution for this??? Someone mentioned maybe it is an ABS issue, causing the rears to think they are locking thereby pulsing?? Just a thought.

Have you changed the fronts yet? How do you know it was definitely the rear?

Antonioimp
05-22-2011, 09:02 PM
I had the same problem two month ago,turning the rotor at first did not solve the problem but after few weeks my brakes are fine

mnypitEXT
05-22-2011, 09:10 PM
Have you changed the fronts yet? How do you know it was definitely the rear?

Fronts are pretty obvious, steering wheel shakes. Mine is definately rear. I have been around this stuff a long time.

Doc Brown
05-24-2011, 11:39 AM
Fronts are pretty obvious, steering wheel shakes. Mine is definately rear. I have been around this stuff a long time.

Ceramic pads I'm betting? I can't emphasize enough the importance of properly bedding the pads, especially with ceramic pads. I have never had problems from pulsating brakes except when using ceramics pads that were not bedded. Do a Google search on this. Lots of people are having pulsating brake issues on all makes of vehicles. I just went through this non-sense on my HHR. I switched to semi-metallic and my problems went away. I've never used ceramic on my TB.

Properly bedding your new brake pads (http://www.zeckhausen.com/bedding_in_brakes.htm)

One other possibility is bearing run out. And of course the hub bearings are notoriously bad on Trailvoys. Google searching on "automotive bearing runout" will get a lot of interesting info on that subject.

mnypitEXT
05-24-2011, 03:48 PM
Ceramic pads I'm betting? I can't emphasize enough the importance of properly bedding the pads, especially with ceramic pads. I have never had problems from pulsating brakes except when using ceramics pads that were not bedded. Do a Google search on this. Lots of people are having pulsating brake issues on all makes of vehicles. I just went through this non-sense on my HHR. I switched to semi-metallic and my problems went away. I've never used ceramic on my TB.

Properly bedding your new brake pads (http://www.zeckhausen.com/bedding_in_brakes.htm)

One other possibility is bearing run out. And of course the hub bearings are notoriously bad on Trailvoys. Google searching on "automotive bearing runout" will get a lot of interesting info on that subject.

Thanks for the links, I will check them out. I have tried both types of pads, thinking exactly what you are saying here. Are the bearings on the rear the problem or are they the fronts? I thought it was a front end issue. I am thinking I might lean toward that as the solution more than seating brake pads. I have been doing brake jobs for nearly 25 years and even did it for a living for about 8, and have never had a seating problem. I am pretty familiar with the seating process.

Doc Brown
05-24-2011, 05:15 PM
Are the bearings on the rear the problem or are they the fronts? I thought it was a front end issue. I am thinking I might lean toward that as the solution more than seating brake pads. I have been doing brake jobs for nearly 25 years and even did it for a living for about 8, and have never had a seating problem. I am pretty familiar with the seating process.

Front. I've read that they now use ball bearings instead of roller bearings. The ball bearings are less durable but have less rolling resistance. How many miles do you have? My hubs went at 72k and 81k.

BTW, I'm not questioning your abilities, frankly I don't know what they are so I'm laying out what I do know, hopefully to help you or someone else.

mnypitEXT
05-24-2011, 10:13 PM
Front. I've read that they now use ball bearings instead of roller bearings. The ball bearings are less durable but have less rolling resistance. How many miles do you have? My hubs went at 72k and 81k.

BTW, I'm not questioning your abilities, frankly I don't know what they are so I'm laying out what I do know, hopefully to help you or someone else.

My shake is definately in the rear, so, although my fronts might need attention, I dont think this is my vibration. URGH. Another possibility gone. Mine has 90k on it and aside from this issue, I have only had to replace the heater resister and the shifter cable. Both common, or at least I found many on here that had the same issue. Came in handy, because I asked, and had my answer in about 3 seconds. This one seems to be baffling everyone.

rburke65
06-06-2011, 03:31 PM
Experiencing the same problem with an '04 Envoy. Wifes SUV and she is a cauious driver, no drag racing for her, 90% city driving. She has tons of pad and rotor thickness left. The serverity of pulsing was reduced , strangly enough, after I replaced the 2 stepper motors on her tach and speedometer a month ago? But now it has returned in serverity in both of our opinions. A friend says it's the ABS sensors? Anyone have any opinions on this "guess"? And can they be replaced by the backyard mechanic? I have it on jack stands as I type this with new pads and rotors ready to be installed. Thanks.

Antonioimp
12-06-2011, 09:02 PM
I took the truck to the shop the turned the disc and installed new pads the vibration now is gone.

pinewagon
01-13-2012, 12:12 PM
Ok, I think we are all chasing our tails here - Has anyone ever owned a car or truck with this issue before? New rotors every 30k?

I did the burn-in, bled the system, and bought slotted rotors, and I still develop chatter before long.

This is a design flaw.

I am curious if it is more prevalent on the earlier design brakes than the later, and if a conversion is possible?

Do the Saab/Isuzu/Olds etc. variants have the same problem?

Also, is there a service bulletin at gm that addresses this?

2004 Envoy I6 4wd

NYRECONMARINES
01-13-2012, 03:02 PM
Check your ABS wires.

mnypitEXT
01-27-2012, 09:19 PM
Happy to report the problem is solved. Have absolutely no idea what finally fixed it, but I went nutz at Autozone. I bought 4 new rotors, 4 new calipers, and all new pads, the best ones they sell(cant remember the name right now). So far I have gone about 10k miles and absolutely no problems. That is also with a lot of towing, and my new boat is 24ft and weighs over 5k fully loaded up with gas, coolers, fishing gear, and 7 people in the Trailblazer(5 adults and 2 children). I also replaced all the shocks and struts with the HD bilsteins.

Autozone was offering a $$40 gift card for every $100 you spend online, so how could I go wrong?? It was at nearly 100k so it needed some love anyway. I put new tires on it about 5k ago and it is like a new vehicle. Everything else is solid and like new underneath.

Only issue I have now is what sounds like a pulley squeeling. From having an LS1 Camaro for so long, I just assumed it was the upper tensioner, but it still does it even after I replaced it. So looking at the lower next.

Dale 3
02-12-2012, 09:58 AM
I also have a pulsating issue, but I feel it more in the brake pedal and its more dominate when I driven for awhile and I slow down from higher speeds. I replaced front rotors and pads about a year ago and everything was find except for the pedal felt kinda spongy. I've had the pulsating for about 3 months now. I did find a caliper slide pin stuck the first time I did the brakes and replaced it.

mnypitEXT
02-12-2012, 10:52 AM
I also have a pulsating issue, but I feel it more in the brake pedal and its more dominate when I driven for awhile and I slow down from higher speeds. I replaced front rotors and pads about a year ago and everything was find except for the pedal felt kinda spongy. I've had the pulsating for about 3 months now. I did find a caliper slide pin stuck the first time I did the brakes and replaced it.

If you are feeling it in the pedal and not in the steering wheel then it is rear, not front.

Dale 3
02-13-2012, 09:39 AM
If you are feeling it in the pedal and not in the steering wheel then it is rear, not front.

Do you think its warped rotors, their not that old?

sdb179
10-30-2012, 08:03 PM
I am also one of the hundreds having this problem. I replaced my back rotors with EBC rotors and front with some rotors i got from autozone. (bought slotted EBC for the front but they sent me rotors that need the EXT caliper) I also replaced the pads with EBC Green Stuff. The chatter started again within 500 miles. :hissy: I was assuming the problem was the calipers as my right rear caliper did have a stuck piston. I got it moving again an put the same caliper back on. My plan as of now is to get all new calipers for my next brake change (then i can use the slotted front EBC rotors i bought before).

Did anybody ever figure this problem out?