stockhome Posted September 18, 2012 Posted September 18, 2012 On my last track day I experienced problems with juddering brakes. Wasn't to bad at first but as the brakes got hot it got worse and worse. Had not had any problems before but ever since I have felt a pulsing through the brake pedal. This afternoon I swapped my front discs for an old set that still had I bit of life left. This has cured the problem, my question is can I do anything with the old discs as they are about 50% used or do I buy a new set?
fentuz Posted September 18, 2012 Posted September 18, 2012 I'd keep them. I had similar things and it appears that it comes from the caliper design itself; the bottom sliding pine/bolt tend to get "jammed" and the caliper doesn't slide equally on the 2 sliding bolt causing jamming when hot... To solve it, I tend to go and clean everything with a old tooth brush and copper grease.
jimbo07g41 Posted September 18, 2012 Posted September 18, 2012 Hi Sheldon, if you take the discs to a good engineering shop you could get a light skim. But it will depend on how much they charge and what the thickness of finished discs will be, to whether it is worth while. Jamie
stockhome Posted September 18, 2012 Author Posted September 18, 2012 The pads are rs42s I have been doing a bit of reading and apparently most problems can be attributed to brake transfer. as described in this article http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths it advises to scrub the disk to remove the uneven build up, has anyone had any experience of this? does it work??
Steve J Posted September 18, 2012 Posted September 18, 2012 Yes lots of issues and its possible if the transfer isn't too bad but if it changes the metallic structure to cementite then skimming is the only answer. I swapped from pagids due to the transfer problems.
Steve J Posted September 20, 2012 Posted September 20, 2012 I currently have Mintex 1155. They're okay. Don't have the same stopping power as RS14s but I had no transfer issues. Brakes did go soft but I think that is down to a change in brake fluid needed. I only had standard stuff put in a couple of years ago. They absolutely stank though. New pads used quite hard, they really smelled like they were on fire :lol Look at your disks and you should see grey streaks and patches where transfer is uneven. Also with juddering coming through pedal I would think this points to the rears. Fronts tend to manifest mostly through steering. It may however not be (just) brakes. Spent ages trying to solve major brake pedal judder only to find a rear bearing had let go. So check all the bearings, TREs, wishbone movement etc I'd have a go at cleaning up yourself as skimming tends to cost half the price of a set of disks (I think mine were £60 each).
stockhome Posted September 20, 2012 Author Posted September 20, 2012 Right I have cleaned up the disks the best I can with some brake cleaner on the inside face of the front disks they have imprints of the pad Outside Inside So it does look like have some transfer possibly when the car was parked up. I have spoken to Geary at Eliseparts and the Disks come with 25.4mm and need to be replaced when under 23mm. The are just under 25mm at the moment so should be able to get them skimmed. Got to make some phone calls
lummo Posted September 20, 2012 Posted September 20, 2012 If those are the fronts, and that happened when the car was parked up, does that suggest that the pads are still pressing against the disk when the brakes are off? Could you have slightly sticking calipers? Or maybe I'm talking rubbish, as usual...
Steve J Posted September 20, 2012 Posted September 20, 2012 Possible hot spots caused by not cooling brakes enough before stopping. Or standard welding to the disk when damp. Other than that they don't look that bad. My transfer was like someone had smeared the disk with dark grey material. There were clear high spots which were solid metal and couldn't be scrubbed off. If the issues go away when you change disks (borrow some old ones) then it's the disks. If not then it's something else. Try cheap options before shelling out for skimming.
fentuz Posted September 20, 2012 Posted September 20, 2012 Have you clocked the disk on the hub with dti? 3 years ago, my hub got worn out and was told it was all fine... And spent a lot on disk that became "warped" after 600 to 1000 miles I went for the 1st time to top gear and clocked it with martin to find lots of run... They did the work and not issues after...
stockhome Posted September 20, 2012 Author Posted September 20, 2012 Possible hot spots caused by not cooling brakes enough before stopping. Or standard welding to the disk when damp. Other than that they don't look that bad. My transfer was like someone had smeared the disk with dark grey material. There were clear high spots which were solid metal and couldn't be scrubbed off. If the issues go away when you change disks (borrow some old ones) then it's the disks. If not then it's something else. Try cheap options before shelling out for skimming. I have already swapped the disks for an old set and it cures the problem so it is definitely these disks
Steve J Posted September 20, 2012 Posted September 20, 2012 Get them checked then. Assuming it's not warped bells?
stockhome Posted October 9, 2012 Author Posted October 9, 2012 I had the disks skimmed at a local machine shop cost me £50, put them back on and still juddering. Even if I touched the brakes lightly I could feel the pedal pulsing under my foot. In the end I bought a new set of disk rotors from Eliseparts, fitted them and hey presto problem solved. When out for drive today and bedded the pads to the disks and now its as good as ever. Still not sure what the problem was but happy its fixed now
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