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Need to replace pads too or just rotors?
- Thread starter wallyuwl
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Go buy plain cheap Chinese rotors from your local parts store.
Brake clean them with BC spray, then wash them with dish soap and water.
So what if this takes 20 minutes extra?
You can use the old pads, but I would get new ones if they are 1/2 worn or more.
Clean and lube all moving parts - sliders, pins, bores, etc.Make sure the mounting surfaces are clean - the hub, rotor, wheel. I LIGHTLY grease those surfaces.
Brake clean them with BC spray, then wash them with dish soap and water.
So what if this takes 20 minutes extra?
You can use the old pads, but I would get new ones if they are 1/2 worn or more.
Clean and lube all moving parts - sliders, pins, bores, etc.Make sure the mounting surfaces are clean - the hub, rotor, wheel. I LIGHTLY grease those surfaces.
Originally Posted By: stephen9666
Originally Posted By: wallyuwl
Originally Posted By: stephen9666
Have you measured the runout or had a shop measure it?
I don't know what this is.
Here's a (somewhat ghetto) video that describes runout. Most of the info on runout is in the second half of the video. It's only 1:30, so it's a quick video. Long story short, lateral runout is the side-to-side movement of the rotor as it is spun. Excessive lateral runout can cause a pedal pulsation.
http://www.youtube.com/watch?v=dMp5G9J1P48
Again, there are issues other than a "warped" rotor that can cause a pedal pulsation. For example, it could be caused by runout in the hub/rotor assembly, which isn't necessarily due to a warped rotor. Or, it could be caused by uneven pad deposits on the rotor.
Here's another video made by someone. It's poorly shot, but it shows how they measured runout and noted it was out of spec. The person then cleaned the hub. After that, the rotor runout was in spec.
http://www.youtube.com/watch?v=v8dykdHPRR0
Here's the Harbor Freight tool used to check the runout in the last video.
http://www.harborfreight.com/clamping-dial-indicator-93051.html
I'm not saying you're wrong about the rotors being warped, but there are other things to check before saying "well, I guess the rotors are warped AGAIN." It seems to make sense that the issue wouldn't be the pads or rotors, since it seems to keep coming back after you replace the brakes.
That is some good info. Thanks.
So, I should put on new pads and rotors, but make sure to clean the hub really, really, really well (maybe using a wire brush and/or screwdriver) before putting on the rotors. Is this correct?
Originally Posted By: wallyuwl
Originally Posted By: stephen9666
Have you measured the runout or had a shop measure it?
I don't know what this is.
Here's a (somewhat ghetto) video that describes runout. Most of the info on runout is in the second half of the video. It's only 1:30, so it's a quick video. Long story short, lateral runout is the side-to-side movement of the rotor as it is spun. Excessive lateral runout can cause a pedal pulsation.
http://www.youtube.com/watch?v=dMp5G9J1P48
Again, there are issues other than a "warped" rotor that can cause a pedal pulsation. For example, it could be caused by runout in the hub/rotor assembly, which isn't necessarily due to a warped rotor. Or, it could be caused by uneven pad deposits on the rotor.
Here's another video made by someone. It's poorly shot, but it shows how they measured runout and noted it was out of spec. The person then cleaned the hub. After that, the rotor runout was in spec.
http://www.youtube.com/watch?v=v8dykdHPRR0
Here's the Harbor Freight tool used to check the runout in the last video.
http://www.harborfreight.com/clamping-dial-indicator-93051.html
I'm not saying you're wrong about the rotors being warped, but there are other things to check before saying "well, I guess the rotors are warped AGAIN." It seems to make sense that the issue wouldn't be the pads or rotors, since it seems to keep coming back after you replace the brakes.
That is some good info. Thanks.
So, I should put on new pads and rotors, but make sure to clean the hub really, really, really well (maybe using a wire brush and/or screwdriver) before putting on the rotors. Is this correct?
Yes. Good tire shops do this with Scotchbrite on an air tool as a matter of normal procedure.
It is worth the extra 10 minutes - use whatever. Wire brush on drill is great..
BTW, of course you can have the old rotors cut, but the price nowadays [for a good job] will be not that much different than getting new rotors.
And the fact of being cheap or expensive rotors do not guaranty anything anymore.
It is worth the extra 10 minutes - use whatever. Wire brush on drill is great..
BTW, of course you can have the old rotors cut, but the price nowadays [for a good job] will be not that much different than getting new rotors.
And the fact of being cheap or expensive rotors do not guaranty anything anymore.
Originally Posted By: mechtech2
Yes. Good tire shops do this with Scotchbrite on an air tool as a matter of normal procedure.
It is worth the extra 10 minutes - use whatever. Wire brush on drill is great..
I think I'm going to clean the hub with a wire brush on a drill, then replace the rotors and pads with Raybestos Advanced Technology parts. Then check the runout with the HF tool. If there is runout I'll get some of the Raybestos shims.
Yes. Good tire shops do this with Scotchbrite on an air tool as a matter of normal procedure.
It is worth the extra 10 minutes - use whatever. Wire brush on drill is great..
I think I'm going to clean the hub with a wire brush on a drill, then replace the rotors and pads with Raybestos Advanced Technology parts. Then check the runout with the HF tool. If there is runout I'll get some of the Raybestos shims.
Originally Posted By: wallyuwl
Originally Posted By: mechtech2
Yes. Good tire shops do this with Scotchbrite on an air tool as a matter of normal procedure.
It is worth the extra 10 minutes - use whatever. Wire brush on drill is great..
I think I'm going to clean the hub with a wire brush on a drill, then replace the rotors and pads with Raybestos Advanced Technology parts. Then check the runout with the HF tool. If there is runout I'll get some of the Raybestos shims.
sounds like a good plan.... if you would indulge my curiosity and report where the rotor and pads are made?
I can't wait for my Ram's front brakes to wear out so I can get some AT r-300 rotors and AT pads.
Originally Posted By: mechtech2
Yes. Good tire shops do this with Scotchbrite on an air tool as a matter of normal procedure.
It is worth the extra 10 minutes - use whatever. Wire brush on drill is great..
I think I'm going to clean the hub with a wire brush on a drill, then replace the rotors and pads with Raybestos Advanced Technology parts. Then check the runout with the HF tool. If there is runout I'll get some of the Raybestos shims.
sounds like a good plan.... if you would indulge my curiosity and report where the rotor and pads are made?
I can't wait for my Ram's front brakes to wear out so I can get some AT r-300 rotors and AT pads.
Last edited:
Originally Posted By: Texan4Life
sounds like a good plan.... if you would indulge my curiosity and report where the rotor and pads are made?
I can't wait for my Ram's front brakes to wear out so I can get some AT r-300 rotors and AT pads.
I know it has been a bit...
The rotors said made in China. The pads, IIRC, said assembled in North America. So probably made in Mexico of Asian parts. But I've learned that just because something is made in China doesn't mean anything - it matters HOW it is made, now where it is made. Though US, Canadian, German, etc. made things always tend to be good quality.
So far so good on the brake job. Car brakes great. In the process of doing the job I tested the runout and one side had less than 1/1000", and the other had about 1.5/1000", and the criteria for what is considered to not be an issue is 2/1000". I took a wire brush on a drill to the hubs before install. I should have tested the runout on the old rotors before taking them off and cleaning the hub but didn't.
I really hope this is the last time I need to mess with brakes on this car. Haven't done a brake job in almost ten years, but got sick of taking this vehicle in because of pulsation. Took me over 6 hours for an oil change, front break job, replacing some retainer clips, new cabin air filter, and a bunch of small things with the engine (PCV valve, throttle body cleaning, MAF cleaning, spark plugs). But it was all done carefully and correctly, so it was worth it.
sounds like a good plan.... if you would indulge my curiosity and report where the rotor and pads are made?
I can't wait for my Ram's front brakes to wear out so I can get some AT r-300 rotors and AT pads.
I know it has been a bit...
The rotors said made in China. The pads, IIRC, said assembled in North America. So probably made in Mexico of Asian parts. But I've learned that just because something is made in China doesn't mean anything - it matters HOW it is made, now where it is made. Though US, Canadian, German, etc. made things always tend to be good quality.
So far so good on the brake job. Car brakes great. In the process of doing the job I tested the runout and one side had less than 1/1000", and the other had about 1.5/1000", and the criteria for what is considered to not be an issue is 2/1000". I took a wire brush on a drill to the hubs before install. I should have tested the runout on the old rotors before taking them off and cleaning the hub but didn't.
I really hope this is the last time I need to mess with brakes on this car. Haven't done a brake job in almost ten years, but got sick of taking this vehicle in because of pulsation. Took me over 6 hours for an oil change, front break job, replacing some retainer clips, new cabin air filter, and a bunch of small things with the engine (PCV valve, throttle body cleaning, MAF cleaning, spark plugs). But it was all done carefully and correctly, so it was worth it.
Sounds like you did a good job. On the rotor that was showing 1.5 thousandths and was near the run out limit, you can take it off and reinstall it on each of the 4 remaining lug nut positions to see if the run out lessens. I don't know if you tried that.
I have found that brakes that perpetually pulsate is usually caused by pad deposition causing parallelism to be out of spec. This is the only thing that will cause the pedal to be 'pushed' back up causing the pulsating sensation. Warped rotors will not cause this, you will usually feel that in the steering only.
It is usually caused by driving style. Women tend to break lighly for longer distances which gets the brakes hot and then when you get to a stop, it 'bakes' the pad material onto the rotor and cause it to have excessive parallelism. The only solution is to retrain the driver, which is difficult when she's your wife and an argument usually ensues.
It is usually caused by driving style. Women tend to break lighly for longer distances which gets the brakes hot and then when you get to a stop, it 'bakes' the pad material onto the rotor and cause it to have excessive parallelism. The only solution is to retrain the driver, which is difficult when she's your wife and an argument usually ensues.
Originally Posted By: mechanicx
Sounds like you did a good job. On the rotor that was showing 1.5 thousandths and was near the run out limit, you can take it off and reinstall it on each of the 4 remaining lug nut positions to see if the run out lessens. I don't know if you tried that.
Ugh! You had to tell me that. Now, being paranoid like I am, I'll have to go try that. Should take less than an hour to figure out and get resolved. I got an electric impact wrench for this job and it is a life saver getting the lugs off (and on). I might take the wire brush on the drill to it again as well.
Sounds like you did a good job. On the rotor that was showing 1.5 thousandths and was near the run out limit, you can take it off and reinstall it on each of the 4 remaining lug nut positions to see if the run out lessens. I don't know if you tried that.
Ugh! You had to tell me that. Now, being paranoid like I am, I'll have to go try that. Should take less than an hour to figure out and get resolved. I got an electric impact wrench for this job and it is a life saver getting the lugs off (and on). I might take the wire brush on the drill to it again as well.
Got that one side down to 1/1000" runout. So now both sides are about that. I rotated the rotor, and went through two or three different orintations of the rotor on the hub, and the numbers were at best the previous 1.5/1000" and sometimes worse. Then I got one that was 1/1000" so I stopped, and put the caliper and rim/tire back on.
A mechanic buddy of mine has told me that with a lot of cars anymore the rotors have to be turned even when brand new. I can't recall which particular model of Caddy it was but that every time they do a brake job on them they have to turn the rotors using the "fancy" brake lathes that can turn them while still on the car.
Doesn't matter what brand of rotor from the cheapest to the high end. The runout exists regardless and it isn't necessarily the the rotors "fault". Its a case of matching the rotor to the car on certain models of cars.
Doesn't matter what brand of rotor from the cheapest to the high end. The runout exists regardless and it isn't necessarily the the rotors "fault". Its a case of matching the rotor to the car on certain models of cars.
Just take the rotors to a machine shop. It's cheaper than buying new ones.
I have heard of people replacing pads and not rotors but not vice versa. Pads only is a bandaid but if you are going to do the complete job do it correctly. I agree that you should upgrade. If this is a perrenial issue you might try a Pontiac Vibe forum and see what seems to work for them. I can't imagine you are the only one with this issue.
Are the rear disc or drum? If they are drum I would recommend having them cleaned and adjusted. That way the whole system will be back in check.
Are the rear disc or drum? If they are drum I would recommend having them cleaned and adjusted. That way the whole system will be back in check.
Originally Posted By: Scott_Tucker
I have found that brakes that perpetually pulsate is usually caused by pad deposition causing parallelism to be out of spec. This is the only thing that will cause the pedal to be 'pushed' back up causing the pulsating sensation. Warped rotors will not cause this, you will usually feel that in the steering only.
It is usually caused by driving style. Women tend to break lighly for longer distances which gets the brakes hot and then when you get to a stop, it 'bakes' the pad material onto the rotor and cause it to have excessive parallelism. The only solution is to retrain the driver, which is difficult when she's your wife and an argument usually ensues.
After over 40 years of fleet ownership, 3 kids, and a whole lot of brake jobs I totally agree. I am still looking for a conventional vented rotor that is truly warped.
MY BIL has a machine shop and agrees after turning thousands of rotors, warping is not the problem. Pad deposition is.
I have found that brakes that perpetually pulsate is usually caused by pad deposition causing parallelism to be out of spec. This is the only thing that will cause the pedal to be 'pushed' back up causing the pulsating sensation. Warped rotors will not cause this, you will usually feel that in the steering only.
It is usually caused by driving style. Women tend to break lighly for longer distances which gets the brakes hot and then when you get to a stop, it 'bakes' the pad material onto the rotor and cause it to have excessive parallelism. The only solution is to retrain the driver, which is difficult when she's your wife and an argument usually ensues.
After over 40 years of fleet ownership, 3 kids, and a whole lot of brake jobs I totally agree. I am still looking for a conventional vented rotor that is truly warped.
MY BIL has a machine shop and agrees after turning thousands of rotors, warping is not the problem. Pad deposition is.
So the thought is that stuff gets on the inside of the pads, and that ends up causing the pulsation?
These rotors said specifically they are made with high precision and don't have to be turned before putting them on. I figure it was a good move to go with the same brand and line rotors and pads. And runout doesn't seem like it will be a problem with the specs where they are at now.
I'll get the rear brakes adjusted and cleaned when we get new tires in the next few months (they are drum). Rear brakes (shoes, drums, hardware) are only a year old. Pedal feel is fine right now. Might do it myself even.
I am a member at GenVibe. I haven't looked on there for people with pulsation issues. The hot topic on there seems to be the p4020 code. LOL.
These rotors said specifically they are made with high precision and don't have to be turned before putting them on. I figure it was a good move to go with the same brand and line rotors and pads. And runout doesn't seem like it will be a problem with the specs where they are at now.
I'll get the rear brakes adjusted and cleaned when we get new tires in the next few months (they are drum). Rear brakes (shoes, drums, hardware) are only a year old. Pedal feel is fine right now. Might do it myself even.
I am a member at GenVibe. I haven't looked on there for people with pulsation issues. The hot topic on there seems to be the p4020 code. LOL.
Originally Posted By: wallyuwl
So the thought is that stuff gets on the inside of the pads, and that ends up causing the pulsation?
Not on the pads, on the rotor. You can check parallelism with a micrometer. Check the rotors in 5 or 6 places. Even .001" to .002" difference can be felt in the brake pedal and it forces the pads outward.
So the thought is that stuff gets on the inside of the pads, and that ends up causing the pulsation?
Not on the pads, on the rotor. You can check parallelism with a micrometer. Check the rotors in 5 or 6 places. Even .001" to .002" difference can be felt in the brake pedal and it forces the pads outward.
Living in the rust belt this is my list of requirements for a good brake job.
When replacing the rotor the hub must be absolutely clean of rust & foreign material.
There is a cone shaped abrasive tool that goes in an electric drill or air tool to clean around the wheel studs removing rust & crud.
I then use brake clean or starting fluid to rinse & then blow dry.
If the rotor is vented I put a light coat of brake grease or spray white grease on the hub surface to prevent rust which also reduces the possibility of the rotor getting stuck on the hub.
Remove the clips that fit between the caliper & pad and clean the rust, then apply heavy brake grease.
This prevents rust from binding the pad in the caliper.
If the caliper has pins & rubber bushings remove the pins and bushings and clean the hole the bushing fits in of all rust then apply brake grease to the bore & bushing. This ensures the caliper is free to float without binding.
Install the rotor on the clean hub and use a couple lug nuts & spacers if necessary to hold the rotor in place.
Install the caliper bracket then clean the rotor with brake clean or starting fluid to remove any grease that may be on the rotor from assembly.
Put a little oil on the wheel studs and the lug nut taper.
Install the wheel and torque to the low to mid end of the manufactures specifications.
Remove the old brake fluid from the master cylinder and replace with new.
This is important to maintain a dry system and prevent ABS malfunctions.
Pump the brake pedal no more than ½ way down to bring the pads into contact with the rotor.
Take the for a slow test drive to verify operation then perform several stops from 50 or 60 mph to 10 mph until the brakes start to fade. This is important to condition and bed the pads which also transfers some pad material onto the rotor.
When the brakes start to fade continue to drive without stopping for a couple miles to allow the brakes to cool evenly.
When the brakes have cooled another test stop should find the brakes will bite very hard.
The job is now done.
To keep the rotors clean it is important in rust prone areas to use the brakes hard at least once a day to prevent rust from becoming imbedded in the rotor.
When replacing the rotor the hub must be absolutely clean of rust & foreign material.
There is a cone shaped abrasive tool that goes in an electric drill or air tool to clean around the wheel studs removing rust & crud.
I then use brake clean or starting fluid to rinse & then blow dry.
If the rotor is vented I put a light coat of brake grease or spray white grease on the hub surface to prevent rust which also reduces the possibility of the rotor getting stuck on the hub.
Remove the clips that fit between the caliper & pad and clean the rust, then apply heavy brake grease.
This prevents rust from binding the pad in the caliper.
If the caliper has pins & rubber bushings remove the pins and bushings and clean the hole the bushing fits in of all rust then apply brake grease to the bore & bushing. This ensures the caliper is free to float without binding.
Install the rotor on the clean hub and use a couple lug nuts & spacers if necessary to hold the rotor in place.
Install the caliper bracket then clean the rotor with brake clean or starting fluid to remove any grease that may be on the rotor from assembly.
Put a little oil on the wheel studs and the lug nut taper.
Install the wheel and torque to the low to mid end of the manufactures specifications.
Remove the old brake fluid from the master cylinder and replace with new.
This is important to maintain a dry system and prevent ABS malfunctions.
Pump the brake pedal no more than ½ way down to bring the pads into contact with the rotor.
Take the for a slow test drive to verify operation then perform several stops from 50 or 60 mph to 10 mph until the brakes start to fade. This is important to condition and bed the pads which also transfers some pad material onto the rotor.
When the brakes start to fade continue to drive without stopping for a couple miles to allow the brakes to cool evenly.
When the brakes have cooled another test stop should find the brakes will bite very hard.
The job is now done.
To keep the rotors clean it is important in rust prone areas to use the brakes hard at least once a day to prevent rust from becoming imbedded in the rotor.
I neglected to answer the question of needing to replace pads with rotors.
That depends on the condition of the pads and how particular you are.
If the pads are smooth & worn evenly reuse the pads.
I have installed new rotors & reused pads that were groved from the old rotor, they pulled to 1 side for a while but they broke in and worked just fine.
I have also installed new pads on severly groved rotors with good results.
When I do a complete brake job on my own vehicle I will save any good pads in case I have a problem that causes 1 pad to wear excessively.
I have installed 1 used pad to keep me going untill I can address the problem with no issues.
A new car dealer will replace a defective warped rotor under warranty and reuse the pads.
That depends on the condition of the pads and how particular you are.
If the pads are smooth & worn evenly reuse the pads.
I have installed new rotors & reused pads that were groved from the old rotor, they pulled to 1 side for a while but they broke in and worked just fine.
I have also installed new pads on severly groved rotors with good results.
When I do a complete brake job on my own vehicle I will save any good pads in case I have a problem that causes 1 pad to wear excessively.
I have installed 1 used pad to keep me going untill I can address the problem with no issues.
A new car dealer will replace a defective warped rotor under warranty and reuse the pads.
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