Hi there.

When I bought my '04 MCS a month ago, the brake pads were very worn. So I replaced them, with AutoZone DuraLast Gold pads. Everything was hunky-dory.

Then one day my brake pedal started pulsing in a very disconcerting manner when I came to a stop (not regular ABS sort of pulsing; a much more dodgy creaky feeling). So I called up my local MINI dealer, and the guy there said it was likely the rotors needed replacing, since they're fairly thin. Made sense.

So I bought a set of PowerSlot Cryo rotors, since a good number of people here mentioned them. They took a while to ship, so I drove on the old rotors for a week and half, going easy on them (and thus largely avoiding the pulsating).

The rotors arrived yesterday. I installed them this morning, thinking they would fix all my problems (including ones that were apparently caused by a bad wheel rotation sensor).

Trouble is, the brakes still pulsated.

So I took it to the dealer. They diagnosed the aforementioned bad wheel sensor, but said as far as the brakes went, they saw nothing wrong with the hydraulics, the pistons, the calipers, etc., and put it down to the aftermarket pads and rotors. They said they couldn't do anything about the brake situation without replacing the pads and rotors with stock OEM parts and charging me $575.

Here, finally, I come to the nub of my gist: after paying $300 on brake parts, I don't want to shell out another $600 and throw away those new rotors, which I understand should be a substantial upgrade over the OEM parts (let me know if I'm mistaken!). So is the problem the brake pads? Something else? What should I do? Am I SOL?

Thanks for reading all that! Any help would be much appreciated.

 

Is it any different with the new rotors vs the old ones? How many miles are on the car?

 

It does seem a bit less with the new rotors, but I definitely felt that unpleasant pedal-shaking pulsating motion a few times today with the new rotors. Hence my decision to take it in. Nigel (my MCS) is overnighting it at the dealer to have a new wheel sensor installed tomorrow morning, so I can't test it again at the moment.

The mileage is about 55,000.

 

Swap the pads around and see if that helps. Also might want to try a few really hard 70-20 stops in a row to remove any possible build up on the pads.

 

Swap them around? Do you mean swap the left and right sets?

Also, 70-20 stop... hard stop, I guess, but what do you mean by 70-20? Please excuse my ignorance.

 

70mph->20mph

This is a strange problem, is it possible that his new pads were screwed up by the original rotors?

 

Does it happen everytime you brake/stop or just some of the time? Does it usually happen at a certain speed? Like if you hit the brakes at 25mph it is fine but at 55mph you get pulsing?

 

Check the disks for abnormal wear to check for warping. Did you bleed the lines for air after you did the job? Checked for brake fluid levels? I would expect the dealer to blame it on aftermarket products. They didn't make any money. They are making an easy $500 by charging you for something you don't need.

 

If these are the "Lifetime Warrantied" Duralast pads, it's no wonder you're having problems. The reason they're lifetime warranty is because they chew through rotors like no tomorrow. They have to make the pad last somehow, and they do that by making it ultra hard.

I wouldn't be surprised if its warping or damaging your rotors pretty severely right off the bat.

Note to self: don't buy important parts (brakes are one of these) at Autozone.

- Matt

 

It sounds like warped rotors. Did you use a torque wrench to install the wheel lug bolts? 88 ft-lb is the spec. If the lugs are overtightened and especially if the lugs are tightened unevenly, your rotors will warp and you'll have a pulsation in the brakes.

Rawhyde

 

I think Rawhyde is on to something. The OP said that he just changed the rotors and had that problem, so it's not the Duralast pads eating the rotors... there wasn't enough time for that. I would bet that a quick retorque of the wheels would help.
There is a chance that the new rotors are not true and are causing similar problems.

FWIW a dealer is only familiar with OEM parts. If you want to keep the aftermarket parts you may need to have an independent shop look at it. They can put the rotors on a dial indicator to see if they are running true.

Do the new rotors have a left and right? Are they directional? If they are that might be an issue also.

 

Rotors aren't directional. Once they are warped they cannot be fixed with a re-torque

 

All he needs to do is have the rotors turned on a brake lathe, then reinstall them while making sure to torque everything properly.

I learned this lesson back in the 80's... I repeated a front brake job about a half dozen times over one summer until I learned the value of making sure the lugs weren't overtorqued! That's one lesson I took to heart after fighting it for about 3 months! Fast forward to today...when I get new tires, I take the wheels to the tire store, get new tires installed on the wheels, take them home, and then I put them on the car myself. NO IMPACT WRENCHES ALLOWED on my lugs!

 

I appreciate that improper torque could lead to things warping. But I'm talking pulsing right after install. Do you mean to tell me that these pads ruined my brand new cryogenically-hardened rotors the instant they made contact? Does that not sound a bit far-fetched?

Now that I know my warning lights coming on wasn't related to the brake issue (they're replacing that sensor tomorrow), I'm less worried that the whole bloody thing is going to fall apart, and I'm willing to test and try a few things out.

So, if these are bad pads (which I will admit is a definite possibility—they were pretty cheap), what brand should I be using?

So what does everyone think of the hard stop technique to try to wear down the pads a bit (in case they got affected by the original warped rotors)? Good idea? Bad?

 

dam. How many miles on your Car. Is this the first brake replacement
how bout the Rears.

1. did you have this problem before you replaced the front pads. Why did you
replace the pads? were they worn or did you have this symptom.
how soon after you did the brake pads it started happening.Because in
your post you said "then one day this complaint appeared.

2. are any warning lamps coming on when your braking, does this pulsation
or warping feeling happening when your not on the brake pedal.

3. Id say install some oem pads see if the feeling in the pedal goes away.
rear rotors out of round can cause this pulsation under braking.

4. Usually fualty wheel speed sensor, a dsc or traction light would come on.
did that occur?


Guidos gone.

 

Your rotors will warp on over tightening immediately. Before you drive even before you put your rims back on.

With regard to the pads, if they were worn wrong they would instantly wear themselves even again with a touch of the brakes so I wouldnt count on those being the culprit.

 

As I mentioned previously, about 55,000.

I'm afraid I don't know. I just bought the car used and they did not keep records of the brake changes.

I did not have this symptom with the original pads, but they were very worn—nearly down to the brake pad sensor. I replaced the pads the first week I had the car.

Good question. I'd say a couple of weeks.

Warning lamps, yes. ABS, DSC, and Flat Tire indicators all turned on a day or two before the pulsing started. I figured this was related to the wheel rotation sensor (which turned out to be right). From then on, I kept a very close eye on tire pressure, and made sure they were always the correct pressure every few days. This kept those indicator lamps at bay somewhat, though they would sometimes come on when I felt the brakes pulsing, or when DSC tried to activate during cornering. When I was told my pulsing issue was related to warped rotors, I thought maybe a warped rotor was messing with the wheel rotation sensor, so I figured I'd wait to see what happened with new rotors. I ordered new ones, and hoped my issues (both the pulsing and the indicator lamps) would go away once the new rotors were installed.

So after installation, I took Nigel for a test spin around a residential block, felt the pulsing (which, when it happens, is not a very subtle thing), and noticed the indicator lamps come on again. That's when I took him in for service.

The pulsing never happens when I am not braking. When it does occur, it's the last 15 feet or so before coming to a full stop. Applying brakes earlier (and hence using less braking pressure throughout braking) prevents the pulsing feeling. So in other words, it occurs at the end of medium to heavy braking.

I had never considered that it might be the rear set. I have done a cursory check, though, and the rear pads have a decent amount of pad left, and the rotors don't have much of a lip on the edge (they don't look too worn). Anyone else have thoughts on this?

Yes. See above.

 

I would suggest resurfacing all four rotors, and replacing the front pads. It sounds like the pads may be the root cause of a lot of your problem. This would be a lot less expensive than doing what the dealer is recommending. I agree w/ one of the previous postings in that I wouldn't recommend using "house brand" brake pads. If you can get a refund for the pads great, but I doubt that'll happen so see if you can upgrade or just bite the bullet and go buy some O.E. pads. And when you install the wheels, don't overtighten as this can definitely warp the rotors right off the bat. HTH

Later

 

If it helps I have a lightly used set of stock pads that I would sell you for $35 shipped and a set of lightly used rotors that I would sell for $120 shipped.

 

Just a little info for reading regarding bedding in. Dave Z is highly respected in the BMW/M community, and a helpful guy. Give him a call, and see what he says.

http://www.zeckhausen.com/bedding_in_brakes.htm

 

lot of misinformation on this thread:

most rotors in use today are not made to be re-surfaced, ever. they simply dont have enough material on them to safely remove any. this can be checked by a competant machine shop. to the guy who said he learned this lesson in the 80's - things have changed, dont machine your rotors.

i suspect your pulsating problem has something to do with air entrained in your hydraulic fluid system. i would invest in (or rent / borrow) a power bleeder and bleed the hell out of all of your brake lines. i'm not sure what it is for the mini, but there is a proper sequence (front left, rear right, etc) which must be followed.

many problems like this are caused during brake change because air finds its way into the abs portion of your brake's hydraulic system. this air is difficult to diagnose and can be very difficult to remove. you must have a power bleeder and be persistant.

i agree that auto-zone replacement brakes are terrible, but they would not have warped your rotors in the first few hundred miles, to the point where you would feel it.

my suggestion is get the power bleeder, and start there, i would be surprised if this didnt solve your problem.

 

You can get a very aggresive "scotch brite" like pad and hit the rotors to knock off any surface film (pad transfer) without cutting. I've used the ones sold at Lowes for the rotory grinders. Pad material is transferred to the rotor surface on properly bedded pads. By re-using the stock rotors you had dis-similar pad material which might be causing the pulsing. You say they pulse more at the end of braking when you lift off the pedal ..... which might mean they are sticking and not releasing off the disc. This could be corrosion between the piston and caliper bore, or sticky float pins.

I am also not a fan of lifetime pads. Hawk HPS or EBC greens would have been my choice for stock replacement. I also replace pads and rotors at the same time, along with a brake fluid bleed / change.

Good luck .... you can do this!! Every slotted rotor I have seen IS directional and must be on the correct side for rotation.

 

Actually not. The pulsing happens at the end of braking, but while I'm still applying the brake. If I lift off the pedal, the pulsing and braking stops immediately, so I don't think they're sticking.

I'm thinking my next step is getting a set of EBC Greenstuffs. Question is, do you guys think my brand new rotors are ruined? I did not use torque wrench, and if anything they were under-tightened, not over-tightened.

As for directional rotors, one box was marked "L" and the other "R." I put the "L" rotor on the left wheel as viewed from driver's seat.

 

You should probably "bed" the pads and rotors, Make several 60 mph to 10 mph stops, enough of them that your brakes smell hot. Then go home and let them cool without setting your parking brake, then do it again. My powerslot rotors came with these instructions.

I would get rid of the duralast brake pads and get hawk or ebc's. I have used Duralast on my "other cars" and have had them do this.

Also as someone suggested powers slots are directional. R and L will be stamped on the rotor.

Also make sure that when you installed them they went on straight and flush. It's possible to get a bit of dirt or crud between the rotor and hub. I have also seen this happen.

Good luck.

 

Methinks you need to look at post #21 above regarding bleeding the lines. If you are not comfortable, get a good independent or MINI guys to do it.

Also, have you taken off the wheels and looked at the rotors to see if they are getting uneven wear spots on them? If it is the ABS or brake system pulsating, it will be at random spots and you likely won't have any uneven wear spots.

If, OTOH, it is warped rotors, I'm assuming you will see wear spots (perhaps slight at this point, but visible).

NOVICE ALERT: I am not a mechanic, and do not play one in real life. Nor have I ever done this, so I'm guessing here. But I did stay in a Holiday Inn Express last night.

Can anyone confirm/debunk my suggestions to help him narrow down his issues?