Extended brake pad bedding period? - FFCars.com : Factory Five Racing Discussion Forum

h82crash · 10-01-2012, 08:11 PM

I'm running 13" cobra rotors and dual piston calipers. Recommended by my parts counter friend, I have Akebono Proact ceramic pads. I have about 800 miles on them and on the driver's outer it looks like about 10% pad contact with the rotor. On the passenger outer, looks to be about 25% contact.

The car stops ok (manual brakes) but the rotors still have most of the hone marks on them. I'm sure the braking will get better as more of the pad begins to make contact with the rotor, but now I'm concerned about uneven rotor wear.

Akebono says there is no bedding procedure but to just drive normally. It's taking awhile and I'm ready for more assertive braking. It would kinda hurt to shelve these pads cause they're $160 a set.

I'm thinking this car is light so I don't have to brake like a large heavy automatic grocery getter, possibly increasing the pad break-in time. Should I be patient?

CraigS · 10-01-2012, 09:32 PM

I wouldn't care about the hone marks still being on the rotor. that will change w/ more miles. But the 10% and 25% contact worries me. Can you be more specific about how you are seeing that please?

ROADRACER83 · 10-01-2012, 10:59 PM

h82crash:

I'm with Craig. The pads should be flat against the rotor all the way across the face of the pad. Make sure they are not cocked in the caliper somehow. Some pads have a bump on the backing plate that needs to fit in a notch in the caliper. You may not need the bump and it won't hurt to grind it off with a die grinder and cutoff disk. I would check the fit of the pad. When they are flat on the rotor you won't need to bed them in just use them hard. Take pics and show us what you are seeing.

Ron

h82crash · 10-01-2012, 11:15 PM

There are only small bands of wear on the rotor surface, most closer to the hub and some near the edge, the rest seems untouched. There may be slight contact in other areas. The pads are seated completely in the calipers.

This one has more wear toward the edge.

vector1 · 10-01-2012, 11:35 PM

as long as the calipers with pads are centered on the rotors you should be good to go. to check for this unbolt the calipers one at a time and push the brake pedal and see if the caliper mounting holes are where they should be, if not shim or do something else to center them. note: you should have done this when the pads were new, now that the pads are used it might effect the results.

Bill Lohmiller · 10-02-2012, 12:27 AM

Based on your wear pattern in addition to whether the pads are installed properly and the calipers are in the right position, I have to ask if your rotors are new or properly turned if used -- or if they were simply "resurfaced"-- as in the surface glaze was broken?

If your calipers and pads are properly installed, but the discs are not new or properly turned, you may be putting on quite a few miles before the pads and discs conform to each other -- especially with the pads you have installed which are not all that aggressive........

Regards,
Bill

h82crash · 10-02-2012, 12:27 AM

The Cobra calipers float, so they are self centering. Yes, the rotors were new also.

I just think the pad material is super hard and will take awhile to bed. Akebono and others who have run these pads say they are low dust. In my mind, that equals super hard or slow to wear. I dunno.

ROADRACER83 · 10-02-2012, 12:27 AM

Tom:

That looks good, but I don't think they are totally bedded in yet. If the calipers are correct you should have maybe an 1/8th of an inch of rotor on the outside that is not contacting the pad and when they get fully bedded in, the parts that are not touching now on the rotor will be all scuffed in. To make sure that the pad spiders are fully into the pistons, press on the brake pedal as hard as you can sitting in the garage to force any misalignment out.

Take that puppy out on the freeway and run it up to 80-90 or so and then find an offramp and hit the brakes hard, just short of locking up the wheels. 1 or 2 of those will bed the pads and the brakes will work well from then on. Make sure that your brake bias is good first and if you are not sure, do a few hard brake applications in a parking lot.

Ron

Bill Lohmiller · 10-02-2012, 12:37 AM

Quote:

Originally Posted by ROADRACER83

Tom:

That looks good, but I don't think they are totally bedded in yet.

Ron

Agree 100% those pads are not bedded in -- but unless that was 800 miles of no stop driving, I don't think that pattern looks good at all....YMMV

Regards,
Bill

h82crash · 10-02-2012, 12:37 AM

I agree, Ron. Just seems to be taking longer to bed. Bill, lots of mountain driving, but as I said before, the car is so light that I don't need to brake as the engine slows me enough to cruise those mountain roads.

Had I not spent a grip of money on these pads, I would have gone to a softer, more aggressive pad by now. As far as they not being aggressive, it stops better now than when I had GT brakes and Hawk pads. So, once these get fully bedded, it should stop like a dog hitting a sliding glass door.

rich grsc · 10-02-2012, 02:18 AM

I dont think they are installed correctly? The pad should make 100% contact.

h82crash · 10-02-2012, 03:00 AM

Quote:

Originally Posted by rich grsc

I dont think they are installed correctly? The pad should make 100% contact.

Well, I guess its possible the calipers are both warped, but I seriously doubt it. I installed these in July and to my recollection the pads were fully seated. Unless these or any pads were made to flatness tolerances to .00001", they wont make 100% contact from the start. Pretty sure in my case the pad surface is just not flat.

Really, I was wondering if ANYONE else had experience with these pads and if my experience was in line.

Bill Lohmiller · 10-02-2012, 05:06 AM

Well, no experience with these exact pads to be sure. However decades of experience putting new pads on numerous vehicles. That is why I am still curious -- are your rotors new or properly turned if used -- or if they are only "resurfaced"-- as in the surface glaze was broken?

This has nothing to do with being warped as such -- it is just that your wear pattern looks like that of a rotor disc that has been previously used and its surface broken rather than turned flat -- ask me how I know

Regards,
Bill

Jack Wojack · 10-02-2012, 05:09 AM

I have some performance pads and it did take a while to get a full contact pattern. If I remember correctly I did have a pattern much like yours. I agree with your thinking that this is a light car and it really doesn't take a lot of pressure to stop and as a result your'e not wearing off the high spots or edges so that you get contact across the pad.

I made a concerted effort to do hard braking...when I come up to a stop light I would check my mirror and if there is no one behind me I would break HARD just short of locking them up. I probably did this 25 times over the coarse of a week or two before I got a full contact pattern. I also got a better feel for how the car felt during braking and built up confidence.

It does take time.

Jack

timp2 · 10-03-2012, 02:14 AM

I think you should try to bed the pads with heavy braking from a high speed, as suggested by others, until you get a full contact pattern on both rotors. What I think you need to be aware of is that if someone pulls out in front of you and you attempt to brake harder than normal one wheel is going to have significantly more stopping power than the other and may cause you to experience an uncontrolled turn, if you get my drift. The pad contact area needs to be the same side to side.

CraigS · 10-03-2012, 01:42 PM

Looks to me like the caliper bracket that mounts onto the axle housing isn't bent correctly so the caliper isn't parallel to the rotor. If you look at the back surface of the rotor is the wear the opposite of the outer surface? IE: outer surface worn near the rotor center and back surface worn at the outer edge.

Sanford · 10-03-2012, 05:01 PM

Could you remove a wheel then put the lugs back on to hold the rotor? Then loosen the caliper mounting bracket bolts. Have someone press the brake and see if the caliper pulls off parallel to the bolt mounting surface. Maybe tighten down the bolts while the brake is pressed and see if the caliper is pulled off parallel to the rotor.

h82crash · 10-03-2012, 08:35 PM

Thanks for all the suggestions. I looked really close last night and it appears the pads are making full contact. It looks like the shinier part of the rotor face was rubbed by a high spot on the pad early on and the rest will take time to look the same. I think all is good. These parts fit so tight that it wouldn't go together if something wasn't fitting right.