subaruowner840 Posted August 19, 2011 Share Posted August 19, 2011 I've had problems with brake pulsation and vibration "warped rotor" a few times. Turning the rotors fixed it in the past. This time at around 84K I replaced the rotors and pads with NAPA's highest quality line. Didn't have the rotors turned, just cleaned the packaging oil off and installed. I did a pretty good pad set in. Nothing the like the sticky that's very detailed, but I was easy on the brakes for a while then moderately got aggressive just for break-in. No problems for a week or so... Then I've got a freaking pulsation again . Only during light-moderate braking and only from 40-35mph. Felt in the pedal and steering wheel. I'd like the input... Link to comment Share on other sites More sharing options...
meier motor sports Posted August 19, 2011 Share Posted August 19, 2011 did you clean the hub of rust and junk? Link to comment Share on other sites More sharing options...
subaruowner840 Posted August 19, 2011 Author Share Posted August 19, 2011 No but there really wasn't much on there. Just spayed some WD-40 on the hub so the new rotors wouldn't stick to the hub right away Link to comment Share on other sites More sharing options...
iNVAR Posted August 19, 2011 Share Posted August 19, 2011 What sort of traffic conditions do you drive in? And do you make it a point to not come to a complete stop after a hard braking session? Link to comment Share on other sites More sharing options...
AZP Installs Posted August 19, 2011 Share Posted August 19, 2011 My guess is that the Napa premium pads may not be up to the task OR something in the bed-in process went awry. As iNVAR said did you make it a point not to come to a complete stop during the bed-in session? For rotors the bed-in session needs to be longer and harder than just a pad bed-in and the cooling period is also longer to season the rotors. For pad bed-in we usually allow for a 15-20 min cool down period after bed-in. For rotors and pads we allow a 30-45 min cool down period. And for cool down I mean sitting parked for that time. -mike Link to comment Share on other sites More sharing options...
JoeFromPA Posted August 19, 2011 Share Posted August 19, 2011 If it only does it from 40-35mph, it's not rotor warpage/pad deposits. You've got a harmonic issue of some sort. Confirm it only happens during a certain speed range, and then ensure your rotors are installed properly and begin checking mounts. Link to comment Share on other sites More sharing options...
Max Capacity Posted August 19, 2011 Share Posted August 19, 2011 Buy Hawk HPS from AZPinstalls. That stopped my pulsating brake padel. In most cases the pads don't shed the dust well enough. Since I have put the HPS pads on, months ago, I have not had the issue return. Oh, I also have my rotors cut on a flywheel surfacer not a lathe. My Machine Shop owner buddy does that to all the rotors now. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
subaruowner840 Posted August 20, 2011 Author Share Posted August 20, 2011 If it only does it from 40-35mph, it's not rotor warpage/pad deposits. You've got a harmonic issue of some sort. Confirm it only happens during a certain speed range, and then ensure your rotors are installed properly and begin checking mounts. I think you're onto something. My daily drive is mostly 40mph with around 10 total stops. About 24 miles a day roundtrip. When I installed the rotors and pads new I think I did really well. I wasn't doing my daily drive stop and go. I drove about 30 miles with some light and medium braking, and a few hard slowdowns without ever really stopping. The pads weren't sitting on hot rotors at any time. It really only happens 40-35 during 1/3 pressure braking. Light braking, and harder braking - nothing. Where would you start? Link to comment Share on other sites More sharing options...
AZP Installs Posted August 20, 2011 Share Posted August 20, 2011 Hmm. Could be a sticking caliper or slider. Did you clean and grease em when you redid the brakes? Link to comment Share on other sites More sharing options...
subaruowner840 Posted August 20, 2011 Author Share Posted August 20, 2011 Hmm. Could be a sticking caliper or slider. Did you clean and grease em when you redid the brakes? Yep. I cleaned and used brake grease on the caliper clips Link to comment Share on other sites More sharing options...
AZP Installs Posted August 20, 2011 Share Posted August 20, 2011 How about the slider? The sliders are more important to clean and grease than the clips. -mike http://www.pbase.com/paisan/image/91072632.jpg http://www.pbase.com/paisan/image/133406601.jpg AIM: AZP Installs | E-mail: paisan@azpinstalls.com | 725 Fath, NJ 07033 | 908.248.AZP1 (2971) | T-1 Certified Amsoil Dealer "Race Tested, Enthusiast Approved!" Link to comment Share on other sites More sharing options...
subaruowner840 Posted August 22, 2011 Author Share Posted August 22, 2011 How about the slider? The sliders are more important to clean and grease than the clips. -mike We put enough brake grease anywhere the pad touches the caliper. I think this weekend I'm going to have my tires rotated, I'll make sure the lugs are torqued properly. Then I'll do an extensive pad set in again. I'll keep you updated. But all the advice, and any additional advice is certainly appreciated. Link to comment Share on other sites More sharing options...
AZP Installs Posted August 23, 2011 Share Posted August 23, 2011 We put enough brake grease anywhere the pad touches the caliper. I think this weekend I'm going to have my tires rotated, I'll make sure the lugs are torqued properly. Then I'll do an extensive pad set in again. I'll keep you updated. But all the advice, and any additional advice is certainly appreciated. The slider pins are not near the pads though. They are where the caliper attaches to the caliper bracket. -mike http://www.pbase.com/paisan/image/91072632.jpg http://www.pbase.com/paisan/image/133406601.jpg AIM: AZP Installs | E-mail: sales@azpinstalls.com | 725 Fairfield Ave | Kenilworth, NJ 07033 | 908.248.AZP1(2971)| T-1 Certified Amsoil Direct Dealer "Race Tested, Enthusiast Approved!" Link to comment Share on other sites More sharing options...
subaruowner840 Posted August 26, 2011 Author Share Posted August 26, 2011 A picture is worth more than I can explain...I just noticed this today. Before there was even pad coloring on the rotors. But here are two pics, guess which one has the problem! Then what to do to fix? Link to comment Share on other sites More sharing options...
zvilly Posted August 27, 2011 Share Posted August 27, 2011 I had the same problem two times in a row. The dust boots on the caliper slider pins broke down and tore, allowing dirt to ge tin. This seized the slider pins. The problem went away when I rebuilt the calipers and changed to a fresh set of pads and rotors Link to comment Share on other sites More sharing options...
subaruowner840 Posted August 28, 2011 Author Share Posted August 28, 2011 Well here's the problem. What caused this? Link to comment Share on other sites More sharing options...
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