We have a problem!

[mLuMaN83]

It sounds like a caliper issue. Might be best to replace in pairs. If it were me, that's what I'd do.

Yeah thats usually how I do things. I think I might look at two reconditioned calipers and slap them on. Gotta make sure this is the issue but I'm pretty sure this is it. I was freaking worried. It feels CRAZY!

[mbeckel]

Yeah thats usually how I do things. I think I might look at two reconditioned calipers and slap them on. Gotta make sure this is the issue but I'm pretty sure this is it. I was freaking worried. It feels CRAZY!

Might want to make sure the rotors aren't damaged from this as well. Might be able to get by getting them surfaced.

[3ZHPGUY]

A quick way to check the caliper, is to get the wheel off the ground with a jack and see if it rotates freely. The fronts will rotate more freely then the rears "because of the transmission drag" but they should have the same resistance on each axle. Remember to put the car in neutral.

FYI on the turning of rotors; that is A BIG NO-NO on Bimmers. They need that mass to dissipate heat and turning them reduces the mass and causes them to warp even faster. As nice as the cross drilled ones look, they actually dissipate heat less due to the reduced mass. So, always replace the rotors with new solids when doing a pad replacement. Both the roter and the pads wear with the heat and friction that are a result of breaking.

[mbeckel]

A quick way to check the caliper, is to get the wheel off the ground with a jack and see if it rotates freely. The fronts will rotate more freely then the rears "because of the transmission drag" but they should have the same resistance on each axle. Remember to put the car in neutral.

FYI on the turning of rotors; that is A BIG NO-NO on Bimmers. They need that mass to dissipate heat and turning them reduces the mass and causes them to warp even faster. As nice as the cross drilled ones look, they actually dissipate heat less due to the reduced mass. So, always replace the rotors with new solids when doing a pad replacement. Both the roter and the pads wear with the heat and friction that are a result of breaking.

Are you saying the solids dissipate heat better than my drilled and slotted rotors? I can't hardly believe that fact. I am requesting proof on this please.

[3ZHPGUY]

Are you saying the solids dissipate heat better than my drilled and slotted rotors? I can't hardly believe that fact. I am requesting proof on this please.

I thought the same about the cross drilled until my first BMWCCA HPDS (High Performance Driving School @ Mid-Ohio) when I was told differently in the class room, by my instructor and many old time participants. And, to conform my thoughts, I started checking out the roters on the cars at the track that day and found very few cross drilled, unless the were over size kits.

[mbeckel]

I thought the same about the cross drilled until my first BMWCCA HPDS (High Performance Driving School @ Mid-Ohio) when I was told differently in the class room, by my instructor and many old time participants. And, to conform my thoughts, I started checking out the roters on the cars at the track that day and found very few cross drilled, unless the were over size kits.

The performance of the rotors I have now compared to the flats is night and day. I just don't get how that's possible for the flats to outperform the cross drilled and slotted rotors.

[3ZHPGUY]

For the street, that may be the case but, at the track you are at the extreme limits of the brakes. That's like I never knew the significant differences you can get in pads and with track pads, that even takes you in to a whole nother world of stopping power and cost. Check out Hawk, the pad choice of many instructors and BMWCCA Club Racers. http://www.hawkperformance.com/motorsports/compounds

[mbeckel]

For the street, that may be the case but, at the track you are at the extreme limits of the brakes. That's like I never knew the significant differences you can get in pads and with track pads, that even takes you in to a whole nother world of stopping power and cost. Check out Hawk, the pad choice of many instructors and BMWCCA Club Racers. http://www.hawkperformance.com/motorsports/compounds

I have hawk pads on my zhp!

[tkundhi]

Let's start from the beginning. What was the original issue you were trying to fix?

There really isn't a need to throw parts at most problems. Suspension problems and brake issues are generally pretty easy to diagnosis by properly inspecting the car. For suspension parts basically make sure there are no cracks and no play. For example on a control arm ball joint, try to compress it. If you can then it is bad and needs to be replaced. I have yet to see a suspension part that has failed and passed visual inspection. You just need to know what to look for. Cracks in rubber, bad.

Regarding a sticky caliper. It will usually stick after you apply the brakes and then pull to one side. Also as someone else mentioned it will heat things up. But, I wouldn't check with your bare hand. You can easily get burned. Brake parts get hot. BTDT.

Now on to some of the brake comments. Sorry but I disagree with several comments about brakes. They are internet lore and misconception. Generally speaking people will say don't turn a BMW rotor. This is because they aren't usually warped. Unless it is a cheapo rotor from China or something similar. Simple comment, OEM does not mean the same as BMW or OE. Be sure to buy OE or BMW quality parts. Now back to the brake rotors. There is a thickness spec. You can turn a rotor if it is warped but still within the thickness spec. But most places won't do that because it is cheaper and easier to simply replace. Plus modern quality rotors are difficult to warp. Ridges, lips and cracks in rotors are bad and generally signs that the parts should be replaced. BTW, some warped rotor claims are nothing more than pad build up.

As far as cross drilled rotors go. Most are simply for show and don't perform as well as a solid vented rotor. Look closely at the cross drilled rotors and you will often find small cracks between the holes. I'm not talking about the expensive ones found on exotics but the stuff most people put on their BMWs. Unless you drive roads like the Tail of the Dragon or CA canyon roads really aggressively it is highly unlikely you are heating up your brake system to the point where brake disc heat dissipation is really an issue. And if you are I can almost guarantee the problem is your fluid and braking technique not the rotor. Plus you should NOT be driving like that on public roads.

All that said you can experience strange brake issues under extreme conditions that are very difficult to isolate. For example a buddy had vibrations coming from the rear of his E36 M3 track car once everything got warm. We replaced the rear rotors. He had OE rotors which where replaced with expensive BMW rotors. He didn't want to waste a whole weekend at the track. But the problem still existed. Turns out there was even a technical term for this symptom, "hot roughness in the rear." One of the guys driving the car was key automotive engineer/racer and mentors the BMW Performance Driving School instructors. Sometimes the mix of parts just doesn't work right together. The expert's words not mine. These guys were running the M3 hard. It was fine for a few laps and then when the pads were up to temp the problem manifested. Slow down for a lap and the problem was gone. Pick the pace back up and it reappeared. For these guys slowing down meant backing off so the car was only a couple seconds a lap slower. Still really fast. This car was on R comp tire, solid rotors and Hawk HT10s. The car never experience the problem again after that weekend.

I run Hawk HT10s on my car with OE rotors and ATE brake fluid. I have yet to boil the fluid. Same setup on my E36 M3. My E30 M3 is also similar with Pagid Orange pads. Point being, buy quality OE rotors and skip the bling if you are really after the performance and durability. If you want cross drilled rotors for the looks, that is fine but don't kid yourself into thinking you have better performance. All you are doing is going through rotors and pads faster. Think cheese grater.

FWIW, our "new" ZHP has slotted rotors and the pedal feel is not as good as the "old" car with solid rotors. These slotted rotors will come off soon. I am going to do an event next month with these rotors as the have a lot of life left. Then they will become spares for the wife's car (old car).

OK back to the OP's issue. If you did all the work yourself the first thing to do is reinspect everything. Make sure all the bolts are tight and properly torqued. Start with the lug bolts. Verify the suspension components are not damaged. If you paid someone to do the work, take the car back to them.

t.

[Newjack]

^^^ Solid points.

However running slotted rotors instead of blanks wont have any difference on pedal feel. They will wear faster as you said, but unless you run stainless steel lines or change pads, pedal feel should be the same.

Luman if you take your car for a drive for a bit just see which wheel is hottest like everyone above me has said. It sounds like a sticky caliper. You should be able to smell which wheel is stuck by the brake dust right after a drive.