Mike B Posted March 27, 2007 Share Posted March 27, 2007 I was bleeding all the brakes the other day and on closer inspection I noticed some damage on the rear brake disks. I have not seen this before and was at a loss to explain it.. Both rear disks have done this, passenger side more so, and both need replacing I would say, asap. The only thing I can think was an off I had at Donnington last month, off track, straight through the mud and water, perhaps cooling them off too quickly; the passenger side to the brunt of the mud and water. Either way, anyone got more experienced idea of what causes this and where the best place to get some sensibly priced rear disks would be? Pics enclosed, as well as the Donnington 4x4 escapade, and the result of the 3 hours it took to get all the crap of the underneath and re-polish her, poor girl… Quote Link to comment Share on other sites More sharing options...
edge Posted March 27, 2007 Share Posted March 27, 2007 Are they cheap discs? Quote Link to comment Share on other sites More sharing options...
JamieP Posted March 27, 2007 Share Posted March 27, 2007 Lots of drilled disks do that Mike, i had some drilled brembos on my evo that did the same thing, get em replaced bud:) Quote Link to comment Share on other sites More sharing options...
edge Posted March 27, 2007 Share Posted March 27, 2007 And i wouldnt even drive that with the disc's in that condition tbh Quote Link to comment Share on other sites More sharing options...
Branners Posted March 27, 2007 Share Posted March 27, 2007 simple answer, drilled disks. Unless they are cast with holes they will crack. Never used drilled disks. JB Quote Link to comment Share on other sites More sharing options...
Gamer Posted March 27, 2007 Share Posted March 27, 2007 My guess is cheap discs that have been drilled, better ones that have holes would have been cast like that from the factory, not drilled afterwards. Quote Link to comment Share on other sites More sharing options...
Lebsteif Posted March 27, 2007 Share Posted March 27, 2007 drilled discs... weak and will crack eventually Quote Link to comment Share on other sites More sharing options...
Gamer Posted March 27, 2007 Share Posted March 27, 2007 It is unanimous Quote Link to comment Share on other sites More sharing options...
Homer Posted March 27, 2007 Share Posted March 27, 2007 There's a pattern here.... I'll say its the drilled discs that are at fault Chris Wilson has been stating for years that drilled/slotted discs a waste of time and are prone to cracking. You're best off with OEM. Quote Link to comment Share on other sites More sharing options...
Mike B Posted March 27, 2007 Author Share Posted March 27, 2007 nice to know! so where d I get some stock smooth ones from then...? mr T? and now I'm off to check my front disks are cast... Quote Link to comment Share on other sites More sharing options...
Mike B Posted March 27, 2007 Author Share Posted March 27, 2007 just to make me sound like even more of a muppet....; Brake saga solved… After a dodgy squishy pedal feel, and hours spent asking questions about bleeding abs systems, trawling through manuals, asking questions on here, doing all the diagnostic checks on the master cylinder, replacing all the fluid twice, and generally getting all paranoid I discovered just how stupid I can be.. Jspec brakes have two cylinders on the front calipers and one bleed point. I had forgotton that my fronts have 6 cyinders and TWO bleed points on each caliper, one hidden from view. I’d only been bleeding one. The other had more air than fluid in it. ….DUMB….ASS…. Quote Link to comment Share on other sites More sharing options...
Stevie Boy Posted March 27, 2007 Share Posted March 27, 2007 simple answer, drilled disks. Unless they are cast with holes they will crack. Never used drilled disks. JB Exactly, as Jamie mentioned even high quality Brembo's crack when given enough stick. Maximum permissable perforation crack length is 5mm over this your discs are shot mate. Quote Link to comment Share on other sites More sharing options...
Pig Posted March 27, 2007 Share Posted March 27, 2007 You're best off with OEM. Dont you find they overheat too easily? I am on my second set and warped them in about 6 months Quote Link to comment Share on other sites More sharing options...
edge Posted March 27, 2007 Share Posted March 27, 2007 just to make me sound like even more of a muppet....; Brake saga solved… After a dodgy squishy pedal feel, and hours spent asking questions about bleeding abs systems, trawling through manuals, asking questions on here, doing all the diagnostic checks on the master cylinder, replacing all the fluid twice, and generally getting all paranoid I discovered just how stupid I can be.. Jspec brakes have two cylinders on the front calipers and one bleed point. I had forgotton that my fronts have 6 cyinders and TWO bleed points on each caliper, one hidden from view. I’d only been bleeding one. The other had more air than fluid in it. ….DUMB….ASS…. I know how you feel. At least you wont forget next time But its a good feeling when its something simple, then you get kicked again finding that Quote Link to comment Share on other sites More sharing options...
Stevie Boy Posted March 27, 2007 Share Posted March 27, 2007 Dont you find they overheat too easily? I am on my second set and warped them in about 6 months Might be time for some bigger brakes dude if your running a power increase way above what OE were designed for! Otherwise stock up on new ones and try not to cook them so much! Quote Link to comment Share on other sites More sharing options...
Homer Posted March 27, 2007 Share Posted March 27, 2007 Dont you find they overheat too easily? I am on my second set and warped them in about 6 months Do you mean fade? Overheating and warping are different things. If you warped the discs you didn't cool them down properly (or you had an accident - but I know that didn't happen) Quote Link to comment Share on other sites More sharing options...
Homer Posted March 27, 2007 Share Posted March 27, 2007 Might be time for some bigger brakes dude if your running a power increase way above what OE were designed for! Otherwise stock up on new ones and try not to cook them so much! No, it's not the brakes fault, its his driving Bigger brakes won't help if you don't cool them down sufficently before coming to a stop. Quote Link to comment Share on other sites More sharing options...
Wez Posted March 27, 2007 Share Posted March 27, 2007 nice to know! so where d I get some stock smooth ones from then...? mr T? and now I'm off to check my front disks are cast... Give Steve Manley a call, details in my Sig Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted March 27, 2007 Share Posted March 27, 2007 Mike it probably is due to the rapid cooling of them, rears do an awful lot less braking than the fronts, especially as you have the big 6 pots up front. They arent cheap discs, they are DBA's. PM me and I will go through a few bits with you. Quote Link to comment Share on other sites More sharing options...
Stevie Boy Posted March 27, 2007 Share Posted March 27, 2007 No, it's not the brakes fault, its his driving Bigger brakes won't help if you don't cool them down sufficently before coming to a stop. Didn't wanna comment on his driving, it's like the male equivalent of asking a woman bout her age and weight! Quote Link to comment Share on other sites More sharing options...
Kite Posted March 27, 2007 Share Posted March 27, 2007 No, it's not the brakes fault, its his driving Bigger brakes won't help if you don't cool them down sufficently before coming to a stop. This might sound stupid... But I´m just curious how should one cool down the brakes? Drive for a while and avoid braking? Quote Link to comment Share on other sites More sharing options...
SimonB Posted March 27, 2007 Share Posted March 27, 2007 DBA specifically say that their drilled disks are not for track use - the reason being they crack. The grooved and plain ones they state as being for street or motorsport/racing. Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted March 27, 2007 Share Posted March 27, 2007 DBA specifically say that their drilled disks are not for track use - the reason being they crack. The grooved and plain ones they state as being for street or motorsport/racing. Simon, I had a long chat with DBA Tech before buying them and they have been just on numerous dry track days with absolutely no issues. I was a long way from easy on my cars brakes. If we were talking about fronts I may tend to agree. Quote Link to comment Share on other sites More sharing options...
Homer Posted March 27, 2007 Share Posted March 27, 2007 Drive for a while and avoid braking? Not avoid braking, simply drive for a while without heavy braking before coming to a rest. On track days they'll say do a good couple of laps (a good few miles) cooling off after a hard drive. Imagine, discs and pads glowing red hot and smoking (they really do), then you pull up to a full stop. The area where the pads sit on the disc will cool much slower than the rest of the disc - instant warped disc. Quote Link to comment Share on other sites More sharing options...
Mike B Posted March 27, 2007 Author Share Posted March 27, 2007 Terry drove the car 200% harder than I have so that's what made me think the rapid cooling at donnington did it... It was wet and the car didn't really use the brakes at all - also it's only the outside of the disk that cracked... the inside is perfect.. I virtually set my old jspecs on fire and they didn't warp or crack, just faded, and smelt.. either way it's time for some new ones me thinks... Quote Link to comment Share on other sites More sharing options...
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