Macky Posted July 29, 2014 Share Posted July 29, 2014 Hi guys, I'm looking at getting new front brakes, but I just want to make sure I definitely need them first. Not sure if I may be able to get away with a skim instead. The symptoms I am getting: -High speed braking - steering wheel wobble and car vibrates mildly. -Low speed braking - slower pulsating feeling through the pedal and car comes to a stop 'unevenly' if that makes sense. -Any speed, NOT braking - a quiet tap from the disc on every rotation, sounds similar to having a stone stuck in your tyre. I have also got some unusual wear on the disc so have taken these pictures to show. The pads have life in them and so do the discs...see what you think Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted July 29, 2014 Share Posted July 29, 2014 Your disc's are warped, you could try skimming, but i would just replace, as those look like they have been pretty overheated/cooked by the micro cracking visible. Quote Link to comment Share on other sites More sharing options...
Ewen@Clark Motorsport Posted July 29, 2014 Share Posted July 29, 2014 As Tricky-Ricky says they have had a bit of heat through them, I would be looking at what pad compound you are running and stepping up to something with a higher heat range Quote Link to comment Share on other sites More sharing options...
HAMLNJ Posted July 29, 2014 Share Posted July 29, 2014 mine need changing next week, front and back. i have been told you wear your pads through much more with groved and drilled disks. so much you burn through pads two much?? Quote Link to comment Share on other sites More sharing options...
RickyZ Posted July 29, 2014 Share Posted July 29, 2014 I've got slight cracking in mine. It was an advisory in my MOT. My mechanic said they'll be fine but keep an eye on it and change them if the cracks get bigger. If I was having issues though I would bite the bullet and get new disks/pads; otherwise you might find yourself chucking new pads away for no real reason Quote Link to comment Share on other sites More sharing options...
Ewen@Clark Motorsport Posted July 29, 2014 Share Posted July 29, 2014 I've heard that before but its not correct, pad wear has to do with the pad compound and how much you use the brakes Quote Link to comment Share on other sites More sharing options...
Ewen@Clark Motorsport Posted July 29, 2014 Share Posted July 29, 2014 I've got slight cracking in mine. It was an advisory in my MOT. My mechanic said they'll be fine but keep an eye on it and change them if the cracks get bigger. If I was having issues though I would bite the bullet and get new disks/pads; otherwise you might find yourself chucking new pads away for no real reason Micro cracking like the ones in the pictures is nothing to worry about, you just need to monitor them and change them once larger crack start to appear Quote Link to comment Share on other sites More sharing options...
Marcus01 Posted July 29, 2014 Share Posted July 29, 2014 Are the discs EBC turbo grooves, only 3 grooves in the disc. If they are brake judder is common on this pattern of disc, if you read the small print in the guarantee I believe EBC advise Procut disc skim after fitting new to eliminate problems later. If the cracking is micro and only in the surface and not around the grooves there is a good chance skimming is an option. Quote Link to comment Share on other sites More sharing options...
Macky Posted July 29, 2014 Author Share Posted July 29, 2014 Okay cheers for the advice chaps. They were on the car already, but that is the pattern yes tophooker (lol) However they were fine before I had to brake hard from a very spirited speed! They still bite well, but the juddering and cracks/dark spots are just a bit worrying Quote Link to comment Share on other sites More sharing options...
GT Driver Posted July 29, 2014 Share Posted July 29, 2014 (edited) I just got my discs skimmed yesterday mate- front axle. I am running relatively new mtec grooved discs. had exactly the same symptoms you describe above. They seem fine now, but I'm ordering new pads to fit. Edited July 29, 2014 by GT Driver 1 Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted July 29, 2014 Share Posted July 29, 2014 As all the above, however check for a pad deposit (imprint) as that may be all that is wrong. Pad deposit is extremely common and happens when you sit with your foot on the brake at traffic light etc after a spirited drive. Easily burnt off with a bed in procedure. Alex, 1 Quote Link to comment Share on other sites More sharing options...
Jixaman Posted July 30, 2014 Share Posted July 30, 2014 I used to work at Terex, they check at 100x magnification, I will never forget the answer when I asked why so microscopic, "I'v never heard of a crack that got smaller" Quote Link to comment Share on other sites More sharing options...
GT Driver Posted July 30, 2014 Share Posted July 30, 2014 (edited) So my discs are skimmed and have 7 miles on them but I jacked up the car last night and noticed they are still rubbing at a point, is this normal? I can't feel it during driving though where I very much could before. You can hear it in video. Also, here is a close up inspection of the disc after cutting, note the cutting lines of possible high spots: Any thoughts? Edited July 30, 2014 by GT Driver Quote Link to comment Share on other sites More sharing options...
Marcus01 Posted August 7, 2014 Share Posted August 7, 2014 The lines are known as ghosting, I am betting the inside face has offset grooves to the outside. To eliminate the lines as much as possible a new carbide insert should be used in the cutting tool and the finish cut should be done 1 side at a time to minimise ghosting. The fact you can feel a rub suggests the symptoms of judder have been treated but not the long term cause of the judder. IMO the judder will be back within 1500 miles. Sorry to be the bearer of not good news, time will tell. Quote Link to comment Share on other sites More sharing options...
GT Driver Posted August 7, 2014 Share Posted August 7, 2014 (edited) Well so far so good. I have put new pads in, so see if there any improvement over the long term. I get so many varying opinions about what is actually causing it. Fact is, I should have changed the pads at the time of changing the discs and I've put it down to poor pad to disc transfer. Time will tell indeed. If it's the case it returns then the discs are being binned. Edited August 7, 2014 by GT Driver Quote Link to comment Share on other sites More sharing options...
Marcus01 Posted August 7, 2014 Share Posted August 7, 2014 If it returns, it will not be the fault of the discs. Quote Link to comment Share on other sites More sharing options...
GT Driver Posted August 7, 2014 Share Posted August 7, 2014 Care to share a thought on what you think is the cause? Quote Link to comment Share on other sites More sharing options...
Marcus01 Posted August 7, 2014 Share Posted August 7, 2014 In my experience, probably the wheels. Take some pictures of the mating face of the wheels and post up. I will have a look. Quote Link to comment Share on other sites More sharing options...
GT Driver Posted August 8, 2014 Share Posted August 8, 2014 In my experience, probably the wheels. Take some pictures of the mating face of the wheels and post up. I will have a look. Interesting- good point. I did have a lot of paint flaking on the inside of the wheel from fitting and removing. Would a good clean sort it out do you reckon? Quote Link to comment Share on other sites More sharing options...
Marcus01 Posted August 8, 2014 Share Posted August 8, 2014 It would not do any harm, always keep the mating face of wheels clean. 1 Quote Link to comment Share on other sites More sharing options...
GT Driver Posted August 8, 2014 Share Posted August 8, 2014 Well.... had front wheels off today. Discovered a lot of flaked paint on 1) Disc hub surface and 2) Wheel mating surface. Scraped a ridiculous amount of paint off. The wheels were refurbed at some point and the quality around the hub area was not great. I cleaned it up fairly well so hopefully it's made an improvement. Quote Link to comment Share on other sites More sharing options...
Marcus01 Posted August 9, 2014 Share Posted August 9, 2014 For sure that is your problem, get the mating face of the wheels back to nice clean aluminium. REMOVE all the powder coat. 2 Quote Link to comment Share on other sites More sharing options...
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