Quiet but juddery Ferodos or noisy non juddery Carbotechs
Discussion
This is driving me mad now. Evo 8 for all the difference that should make. AP6 pots, 330mm. The Ferodo DS2500 pads were supplied new with the brake kit. Frankly, they're crap. I wouldn't mind them not being as strong as I want on the road, but the pad transfer and resultant judder is pathetic.
I was about to replace them with the Carbotechs, had the calipers apart and discovered two pistons in the o/s one not moving as freely as I was happy with. Cue a couple of hours chew on freeing them off.
I've now fitted the Carbotechs and been out a couple of times to bed them in. The judder is all but gone, but the noise from the new pads, whether they're applied or not, is hellish. I can hear them scraping the discs and squeaking without them on, even though they're free. The car will roll on the slightest incline, so they aren't hanging on to any great degree, but are still obviously just touching the disc enough to make noise. It's extremely noticeable with the window down. This despite me spraying the back of the pads with an adhesive specific to the job, which sticks the pads to the pistons and is supposed to pull the pads back from the discs when the pedal is released.
Contrary to the usual complaint with Carbotechs, I have no squeal when they're applied, but the scraping noise while they're on sounds like I've put them in back to front! The stopping power is fine though.
Is this likely to settle after a few hundred miles or am I wasting my time with both sets? If I have to buy again, I will, but it'll have to be a guaranteed result next time.
I was about to replace them with the Carbotechs, had the calipers apart and discovered two pistons in the o/s one not moving as freely as I was happy with. Cue a couple of hours chew on freeing them off.
I've now fitted the Carbotechs and been out a couple of times to bed them in. The judder is all but gone, but the noise from the new pads, whether they're applied or not, is hellish. I can hear them scraping the discs and squeaking without them on, even though they're free. The car will roll on the slightest incline, so they aren't hanging on to any great degree, but are still obviously just touching the disc enough to make noise. It's extremely noticeable with the window down. This despite me spraying the back of the pads with an adhesive specific to the job, which sticks the pads to the pistons and is supposed to pull the pads back from the discs when the pedal is released.
Contrary to the usual complaint with Carbotechs, I have no squeal when they're applied, but the scraping noise while they're on sounds like I've put them in back to front! The stopping power is fine though.
Is this likely to settle after a few hundred miles or am I wasting my time with both sets? If I have to buy again, I will, but it'll have to be a guaranteed result next time.
GreenV8S said:
I'd try to figure out what's causing that juddering. I've found DS2500 pretty good in fast road and track use. Are you in the habbit of holding the car stationary with your foot on the brakes when they're hot? That seems to aggravate pad transfer / hotspots / martensite formation.
Hi, no I really don't do that with the brakes while stationary. I think I'm going to use the Carbotechs to clean the disc up, then try the DSS2500s again, but They've never really impressed me from the off to be honest. The Carbotechs throw you into the seatbelt at a ton. The Ferodos are pretty lame by comparison, but the noise of the new ones, even when not actually braking, has to be experienced to be believed! Unless someone says they've had this and it takes a few hundred miles of living with it before they calm down, I can't have it.Maybe I just need to use the brakes harder generally.
I " may " have just doped out wtf is going on here, having been on an experimental late night excursion on quiet roads with various windows down. If I'm right, it's a very untimely coincidence and I'll embarrass myself with a full and self deprecating on the spot report tomorrow evening, by which point I'll be filthy and pissed off if I've still not fixed it. Or filthy and massively cheered up if I'm right.
At least I've got everything in the garage I need to deal with it if I am right, so one less thing. And you'll all have someone to point and laugh at either way!
At least I've got everything in the garage I need to deal with it if I am right, so one less thing. And you'll all have someone to point and laugh at either way!
GreenV8S said:
Well, that's encouraging - fingers crossed you're found the problem.
On the offchance that isn't it, did you clean and grease everything when fitting, and follow the bedding-in instructions?
Other than the two sticky pistons I found on mine, there isn't a great deal to go wrong with APs as calipers go, very simple design really. Nothing goes through the pads, mine slid into position very nicely, tiny bit of grease on the contact edges. They're secured with a shim from above which sits under two hollow pins that look partly like they're there to keep the pads in and partly to prevent the caliper from deforming when the allen bolts that go through them are tightened, and that's all that keeps things in place. On the offchance that isn't it, did you clean and grease everything when fitting, and follow the bedding-in instructions?
Sorry if you already knew all of that, I just ended up rabbit holing!
I've been pretty aggressive with the bedding in, due to the visible deposits the DS2500s had left on them. After driving the 10 miles to my chosen spot and getting the brakes up to temp with moderate use, I did 10 hard stops from about a ton to walking pace. When I pulled in to have a look at how the discs were faring, there were clouds coming from the calipers. I'll need to do it again, the discs were much cleaner than before and the judder was almost gone after a 20 minute cool down drive with no brake use, but I think I triggered the ABS a couple of times, so they won't have benefitted as much as they might.
Update. I'll get the part where I show myself to be the pillock I'm often accused of out of the way first.
The grating I could hear was the rear Brembos. On the metal. Fortunately, the only metal to metal contact made was the edge of rhe baking plate hitting the raised lip on the edge of the disc, and the contact surface has remained unscathed. It sounded horrendous, and I should have guessed that something other than what I was actually working on was amiss, but I've had such a ballache with the fronts that it never crossed my mind I was going to have the rears join the party at the exact same time.
Fortune clearly favours the stupid though, as I already had a set of XP10s in the garage for the rears. I've never personally changed the rear pads on this car until this morning, and it turned out to be a doddle, nothing seized, everything apart and back together again with no probs.
I took the opportunity to clean the mating faces of the wheels and hubs, chamfered all around the edges of the pads, tiny bit of grease on all brake parts as required. Spent about an hour and 20 mins all in. Then almost ruined the day with one moment of educational sub-normality, by tightening the locking wheel nuts up and forgetting to remove the keys from the nuts. Again luck intervened, and after running the car around the car park where I live, I found one on the ground outside and one in the garage.
After all that, the front brakes are still squeaking when not applied, and quiet when on! Overall though, I'm getting happier.
The grating I could hear was the rear Brembos. On the metal. Fortunately, the only metal to metal contact made was the edge of rhe baking plate hitting the raised lip on the edge of the disc, and the contact surface has remained unscathed. It sounded horrendous, and I should have guessed that something other than what I was actually working on was amiss, but I've had such a ballache with the fronts that it never crossed my mind I was going to have the rears join the party at the exact same time.
Fortune clearly favours the stupid though, as I already had a set of XP10s in the garage for the rears. I've never personally changed the rear pads on this car until this morning, and it turned out to be a doddle, nothing seized, everything apart and back together again with no probs.
I took the opportunity to clean the mating faces of the wheels and hubs, chamfered all around the edges of the pads, tiny bit of grease on all brake parts as required. Spent about an hour and 20 mins all in. Then almost ruined the day with one moment of educational sub-normality, by tightening the locking wheel nuts up and forgetting to remove the keys from the nuts. Again luck intervened, and after running the car around the car park where I live, I found one on the ground outside and one in the garage.
After all that, the front brakes are still squeaking when not applied, and quiet when on! Overall though, I'm getting happier.
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