Olorin2

iTrader: (6)

Hey guys-

I just installed new pads and rotors. I let the car sit until this morning, and today I bled the brake system with speedbleeders. However, I noticed that the brake pedal is going practically to the floor and hardly giving any resistance. Nothing is leaking from the bleeders, but I noticed that the front calipers are moving a lot on the sliders, and the rotors are still loose - even after depressing the brake pedal many times.

I can't seem to tighten the caliper bolts any more than they are now. I thought maybe the piston isn't moving, but it pushed back in with ease yesterday and never felt like it was seized (not to mention I had to push it all the way in for the new pads).

I'm still currently troubleshooting, but I'm really hoping I can get some advice quickly. Can anyone explain why I'm not feeling resistance from the pedal, and why the front calipers will not compress the pads and rotors?

Thanks everyone!

justjim

When you change pads you have to push the pistons way in. The pistons won't return to meet the pads on their own you have to pump the pedal several times to get them there. You should not bleed the fluid until you have pushed the pistons back out and the pads meet the rotors. Sounds to me like you bled them before the pistons cam back and you didn't get all the air out. When the pads moved towards the rotor, the fluid level drops and it is also possible that you let the master cylinder go dry during your bleeding procedure and you let air into the system (it has happened to me and I know better).

See if by mulitple pumps you can get the pads to move back into contact with the rotors. Then rebleed the entire system again, paying careful attention that the master cylinder reservoir does not go dry. I'm reasonably certain your problem is air in the system due to an incomplete/incorrect bleeding procedure.

Olorin2

iTrader: (6)

Thank you very much. In fact, I didn't give it many pumps before bleeding. I did pump the brakes a few times after the pad change, and I figured that would give the piston a chance to rotate towards the rotor enough.

I should have mentioned that I still hadn't bled the front driver's caliper when I posted the message. When I just did this, the brake pedal felt more firm. There was a ton of air in that line. And I'd been watching the MC during the entire bleeding process, and the fluid never fell below the minimum fluid line.

I'm going out to bleed all four calipers again. In the meantime, if anyone has any more input, it would be greatly appreciated! And thanks again to justjim for the prompt and helpful info!

Olorin2

iTrader: (6)

Okay, so I re-bled all 4 brakes again and the pedal feels okay, although not as firm as I'd hoped. There was absolutely no air coming from any of the calipers.

The main problem now is that when I feather the brakes at slower speeds, the brakes groan very loudly. Also, if I come to an abrupt stop, I get a kind of clunk/groan - almost like the pad is slipping on the rotor. Right now I can't tell if it's coming from the front or rear.

I also took the front passenger wheel off again, and noted that I can still pull the rotor out a little (opposite side from the caliper), and the caliper itself still has a little movement if I push/pull on the sliders. I know the caliper is supposed to slide on the pins, but I don't recall ever being able to move it with my hand. I don't know if the problem is actually here, or with a rear caliper, but I thought I'd mention it anyway.

I'm just not sure where to go from here, aside from taking everything apart again, which I just don't have time for myself. All parts seemed to install okay and everything is torqued to spec. Can anyone offer suggestions on what might be causing the sounds?

The new rotors do have a zinc plating on them, so I'm not bedding the pads until this is polished down. Actually I'm not going to drive the car any significant speed or distance until I can get this straightened out.

Thanks again for any help.

Edit: One other question: The pads are making a fairly loud metallic sound while driving, when I'm not on the brake. Is this normal because of the zinc plating and new ceramic pads?

laythor

did you follow the directions for breaking in your pads?

Olorin2

iTrader: (6)

Well, as I mentioned, I was holding off on the bed-in process until the zinc plating is polished off (which shouldn't take too long). This is per Rotorpros website, which is the company I bought the rotors from.

Besides, I wouldn't think I'd get loud groaning and a clunk sound even before bedding the pads.

dannobre

iTrader: (3)

The rotor is held on by the lug nuts...so it would be normal to be able to move it when the lugs are loose

There shouldn't be a loud metallic sound when you are on or off the brakes....it is likely that your dust shields is rubbing on something....

You need to get someone that knows what they are doing to help you out...brakes aren't a good DIY if you are a novice....

Olorin2

iTrader: (6)

Dannobre: I appreciate your response. I know these sound like novice questions, but I have actually performed a couple successful brake jobs. This is not to say I'm an expert but I'm just trying to hit every possible angle here. I removed my rotors and pads a while back to paint the calipers and dust shields, and didn't come across any issues.

As for the metallic sound, it's the pads rubbing the rotors as I'm driving, and I can only hear them when I'm driving next to something, like other cars parked on the side of the road. I've had the dust shield scrape in the past, and this isn't it. I'm assuming this will subside as the plating is worn down, and I break in the pads.

But I'm still concerned about the sounds I'm getting when braking suddenly. It actually does feel and sound like one of the pads is slipping on a rotor. Is that possible? Could this have something to do with the parking brake? Seems to work fine, but it reminds me of the sound you might hear when the car is shifted with the parking brake engaged.

Anyway, I'll tackle it again in the morning. Good thing I have off work this week!

Pico

iTrader: (2)

^ I'm guessing you went with slotted and dimpled rotors????

If so I had the same problem with the sound.. The noise is from the air getting trapped between the pad and the dimples not the zinc platting. Some people have this sound problem and other do not - I can't explain that LoL. But it did have me wondering for a while what the problem was and I Have talked to other members here for advice/ solution. I fixed this problem when I went with crossed drilled and slotted rotors... BTW-- I'm using RotorPros as well..

Olorin2

iTrader: (6)

Hey Pico! I read your post while researching rotors and it help convince me to go with RotorPros. But actually, I went with slotted and cross drilled as well. I'm going to start off by removing both rear calipers and pads tomorrow and see what I can find.

Pico

iTrader: (2)

Hmmmmm

I never had this problem with crossed drilled and slotted, only with the dimples, and I have gone through 3 full sets of rotors from RP. --- long story not my or Rps fault in any way.
I guess just make sure the pads are properly seated and the clips are position correctly.

I had a little noise at first but after fully bedding a couple times the sound went away. Your right the the zinc will cause a slight sound-- but the zinc burns off after about 20 miles of normal driving after bedding. This is from my experience.

When you bed the brakes, heat them up good and do the normal bedding procedure. Let them properly cool after you bed -- very important

Olorin2

iTrader: (6)

Awesome man, thanks. At this point I really can't imagine what's wrong, but hopefully I'll find something in the morning. All in all, I'm happy with the quality of the RP rotors, and they look great!

dannobre

iTrader: (3)

The pads shouldn't drag that bad...if it is the rears..you might want to make sure they aren't dragging enough to get hot....

They can be problematic if you don't retract them far enough...

justjim

Like Dannobre says, if you didn't put the phillips head screws in to hold the rotors on (they aren't necessary) they are only held on by the lug nuts. If you then wiggle the rotor it will pull the pads away from the rotor like you noted.

Barring some serious mistake in installment the clunking may come from lack of lubrication on the backs of the pads. I notice this happens if I don't lubricate my track pads and leave them on for a few days after an event. The pads bind up and pop under braking around town. Lubricating them or changing back to the OEM pads with shims and lubrication stops it.

The growling is likely a combination of removing the plating and the cross drilled and slotted rotors which make more noise than blanks.

Lubricate the backs of the pads when you check your installation, put the OEM shims back on the pad backs if you still have them. Then go out and bed the pads in. My guess is that they will quiet down somewhat with time. Should have gone with blank rotors.

Huey52

iTrader: (2)

^ Note that only the OEM front rotors have retaining screws. The rear rotors are just held on by the lugs. The rear caliper pistons require a special tool to rotate them back into the housing fully. You can just use a large set of slip-joint pliers or a 'D' clamp on the fronts tho'.

Concur with copper grease anywhere the pads make contact in their rails and with the caliper piston. and also retaining the OEM shims for the new pads.

There're already excellent DIY's:

https://www.rx8club.com/showthread.p...=brake+pad+DIY

http://www.hi-impact.org/ryang/modify/modify.html

Olorin2

iTrader: (6)

Thanks for the tips guys. I think I was getting a little paranoid after the brake job (which could be a good thing, considering how important they are), and didn't give the brakes enough time to settle in. After driving a bit, there is no more noise, and braking is very smooth and linear. I wouldn't say that I should have gone with blank rotors... they now are as quiet as stock.

I was very careful during the install, and used the grease that Hawk provided on all the pad/caliper contact points. And btw, I did consult pretty much every post concerning brake DIY on this board. The caliper piston "cube" tool I used worked very well. As for the shims, the Hawk pads come with shims already built onto the back of the pad - so it wasn't necessary to transfer the stock ones. And the speedbleeders I installed worked flawlessly!

The only thing I screwed up was with getting the rear rotors reversed. There was no sticker on the rotors to tell me which slotted rotor went on which side, and I completely overlooked it during the install. Looking at pics here and around the Internet, I've seen the slots go both ways. I removed the rear rotors again today and switched them around so the slots are venting towards the back of the car.

The zinc plating is almost completely polished off (only driven a few miles since the install), so I'll probably bed the pads tomorrow.

Pico

iTrader: (2)

Great glad it worked out for you..

Enjoy them!

Huey52

iTrader: (2)

Enclosed is a picture of my front driver's side Racing Brake rotor installed (yes, I got a bit over zealous with the copper grease, but no harm, no foul). The rear orientation of the slots is the same. The internal curved vanes are oriented the opposite btw.

Racing Brake has a diagram showing same on their 'site:

http://www.racingbrake.com/v/main/te...0of%20Rotation

justjim

It's the direction of the internal cooling vanes on CURVED vane rotors that make them directional (right or left), the direction of the slots is not really important. Straight vane rotors (OEM) are non-directional and are interchangable right or left, slotted or not.

Huey52

iTrader: (2)

^ true, but even with straight vanes it looks better to have the slots angled forward, kinda like a circular saw blade's teeth.

btw: the reason for the curved vanes angling aft is that it facilitates more rapid rotor heat dissipation by airflow-centripetal force (radiator effect).

justjim

True it acts like a centrifugal pump (similar to the water pump) pulling air from the center of the hat to the outside of the rotor. First used in racing I believe by the Ford GT40 in Lemans.