I have a 95' M3 and i'm getting massive "rotor warping / build up" after only a few sessions out at Sebring and/or Homestead. I am running OEM M3 calipers with bimmerworld brass caliper guide bushings(Permatex ceramic extreme brake lubricant), NO cooling to the brakes, Centric premium high carbon brake rotors, Hawk DTC-70 pads up front and DTC-60 pads at the rear with Motul 660 brake fluid ( i just switched to Endless RF650, what a difference BTW). After a few sessions the rotors were "warped" so badly that the entire dash was shaking in the braking zones. Attempts to resurface the rotor were unsuccessful. I was told the blade kept skipping and the marks on the rotor showed that when they showed it to me.
My question is: what could be causing this?
1. I don't know how to brake properly? I brake hard and early, slowly come off of the brake as i start to turn in to most corners. I am not gentle when I brake. The car does not have ABS.
2. Should i go with OEM rotors? I was thinking of going for brembo slotted rotors at the rear (even though there are no problems there currently) and the DBA T3 4000 series rotors for the front do you have any thoughts on these?
3. I am changing pads to PFC-08 mostly because they last longer than the DTC70's but also because I am tired of constantly "warping rotors" so I feel like changing everything.
4. Could my calipers need to be rebuilt? What are the signs of a caliper that need to be rebuilt?
5. I have no cooling to the rotors not even the stock cooling ducts. Could that be it? I have been wanting to buy the bimmerworld brake cooling kit but I don't want to buy that if that is not going to fix the problem.
6. Do I not cool down the brakes enough after a session? Cool down lap is taken slowly with almost no braking. After I drive around another 3-4 minutes off track in the parking lot very, very slowly. I do put put on the parking brake when I park the car.
I need help
Last edited by BeeHemDoubleU; 07-09-2018 at 04:36 PM.
Think those rotors come with a 2 year warranty
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When did you grease the pins last?
Unless your old fluid was boiling you are over paying for that stuff. Can't compress a liquid. Your pedal firm with the old sauce?
Last edited by Cobra1956; 07-09-2018 at 04:29 PM.
ME:"I want to make my car faster and lighter"
THEM:" Get out and let someone else drive"
Pins were brand new for my last track weekend greased with Permatex ceramic extreme brake lubricant. I threw the rotors out while blinded with anger lol.
Motul 660 was giving me a horrendously squishy brake feel. I would bleed and bleed and bleed and bleed...etc.... Since switching to this new brake fluid I feel a big difference when the brakes start to heat up since the viscosity of Endless RF650 is much higher than Motul 660 at high temperatures the brake pedal resistance is significantly different (maybe 15%-20% stiffer but I consider that significant and I did not feel the need to bleed the brakes once while at the track). Whether its in my head or I really am feeling the difference I don't know but the one thing I do not mind spending extra money on is brakes.
Last edited by BeeHemDoubleU; 07-09-2018 at 04:37 PM.
How old are you brake lines, Can't compress a liquid. Back of the rotors clean? Hubs okay. Hard to warp a rotor. Got you on the brakes but there has to be a reason. Heat to make one is higher than what you should see on the track. Do you bed in the pads and rotors?
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Do you have an infra red thermometer, or can borrow one? Getting some temps should help.
ME:"I want to make my car faster and lighter"
THEM:" Get out and let someone else drive"
Not saying this is your issue rather food for thought:
- Perform 3-4 medium stops from 45mph. Slightly more aggressive than normal braking. You don't need to come to a complete stop for each pass. This brings the brake rotors up to temperature so they are not exposed to sudden thermal shock.
- Make 8-10 aggressive stops from 60mph down to 15mph. For this set of semi-stops, you want to be firm and aggressive, but not to the point where ABS activates and the wheels lock up. It's important to note that you don't come to a complete stop but rather a semi-stop (~15mph). Accelerate back up to 60mph as soon as you slowed down to your semi-stop.
- The brake pads and brake rotors are extremely hot at this point and sitting on one point will imprint the pad material onto the surface unevenly. This can cause vibration and uneven braking.
- You may notice that your brakes will start fading, and sometimes smoke, after the 6th or 7th pass. This fade will stabilize and will gradually recess once your brakes have cooled down to normal operating temperatures. Drive carefully as your brakes may feel softer for the next few minutes.
- Try not to come to a complete stop and find a stretch of road where you can coast for 5-10 minutes, preferably without using your brakes.
ME:"I want to make my car faster and lighter"
THEM:" Get out and let someone else drive"
Brake lines are SS and a couple years old. Hubs replaced 2-3 yrs ago before I bought the car. Rotor and hub assembly spins freely when the caliper is removed and has no up/down/side/side play at all. This car is only driven to the track, on the track and home from the track. Yes, I bedded the new pads before the track event. I don't have a thermometer but this has happened on 2 sets of different rotors by different manufacturers but I have not tried using OEM rotors. I was considering skipping that step and going to something higher end like the DBA T3 4000 series rotors
Last edited by BeeHemDoubleU; 07-09-2018 at 05:06 PM.
I had a similar problem on my first track day with PFC-08s and OEM rotors, I went out and bought a Bimmerworld cooling kit and that seemed to fix the issue. I will occasionally get a little bit of vibration from the brakes after a few laps that goes away, my working theory is that I’m just not warming the brakes up properly.
That being said, I’ve talked to other E36 guys that don’t run cooling if they’re not on slicks (I am not). It’s possible that removing the dust shields may be enough. You can remove them completely from the front (you’d need to do this anyway with a cooling kit), and if you want to retain a parking brake you’ll have to cut down the rears.
They warp how fast? You do not get through an event? Brakes are all about handling heat. Pads will have more or less torque and work better in different ranges but the actual heat is determined by the speed , weight and how fast you want to stop the car...along with technique. My front duct are actually taped off and I have never wrapped a front. What level driver are you? Just trying to get a gauge of what you are dealing with. I run a lot at CMP and it is very hard on brakes and never had an issue. Better gear might make the difference as the front were vented two piece but these are pretty light cars all things considered. Idea on weight of your car? Also if you are not on slicks you are limited by your tires with the pads you mentioned so there must be something off somewhere.
ME:"I want to make my car faster and lighter"
THEM:" Get out and let someone else drive"
Might not be a big deal but the hub should not spin freely. Not sure if that is what you meant but there should be some load= grease in the sealed bearing.
Have you always had the issue or did it start after you changed something?
Change should be better, same, worse
So fluid we would say better or same
Pins we would think better but not necessarily
Any play in the hubs when pulling on the wheel 12-6 position, 9-3?
All the ball joints and tie-rods good, did you check the rotors for run out?
I would say rotors but since you say twice with two different mfgrs that is probably not it
You run with any other e36? What do they have? IE a 328 is will weigh about the same but have way less brake than an M3 front and rear.
Might the caliper be in need of rebuilding as in sticking due to worn square cut gasket?
The heat has to be coming from somewhere, we just have to find it.
ME:"I want to make my car faster and lighter"
THEM:" Get out and let someone else drive"
With NASA i'm a level 3 HPDE driver. I also run advanced solo with Fara. I run either Toyo Proxes RR or 200 treadwear compound street tires depending on what I want to practice on. I think i'm pretty hard on the brakes. My coaches have always told me I brake hard right from initial pressure. I try to reach the threshold braking point as quickly as possible. My car's ABS is not functioning so I occasionally lockup a tire and modulate to get the tire to spin again pretty quickly(maybe once or twice over an entire weekend)I run the tires hard enough that they get greasy after only a couple laps of running hard. Then I take a sort of cool down lap and go again for 1 or 2 hard laps. I think i'll try taking off the dust shield. Car weighs around 3000-3100lbs im guessing. The rear is completely stripped.
Have you always had the issue or did it start after you changed something? always had the issue. brand new rotor did last me 3-4 sessions before it started to warp
Change should be better, same, worse---I feel any change has pretty much kept everything the same
So fluid we would say better or same---fluid made the brake fade and feel better but not the warping of the rotors
Pins we would think better but not necessarily---i added this at the same time i introduced Endless RF650 so I don't know which made the brakes feel a bit better
Any play in the hubs when pulling on the wheel 12-6 position, 9-3? None at all
All the ball joints and tie-rods good, did you check the rotors for run out? tie rods replaced late 2015 as well as front hub
I would say rotors but since you say twice with two different mfgrs that is probably not it--- both were aftermarket, not OEM
You run with any other e36? What do they have? IE a 328 is will weigh about the same but have way less brake than an M3 front and rear.
Might the caliper be in need of rebuilding as in sticking due to worn square cut gasket? *************when i jack up the car and try to spin the wheel there is always some resistance and the pads are always sticking but I thought this was normal to have some resistance. I don't think the front wheels go a full rotation when I try to spin them when they are up in the air. Could this be it? ******************
The heat has to be coming from somewhere, we just have to find it.
Something I don’t see mentioned - solid caliper bushings can bind. The result is the outboard pad is held hard against the outer rotor surface and slightly higher pedal pressure, possibly inducing biased heat into the inbd/outbd rotor surfaces.
Make sure your calipers actually slide freely on the installed pins.
If the caliper does not slide freely, you are dragging a pad.
To free up the caliper, enlarge the bushing bore using a ~ 3” length of (80G) emery paper passed thru a large cotter pin chucked up in a drill motor to ‘hone’ the bushing bore. Hone the bore until you can easily install the guide pins with you fingers and freely slide the caliper (temporarily remove the pads) on the installed pins.
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Last edited by bluptgm3; 07-09-2018 at 11:55 PM.
From what you posted I would say it is caliper related. Its a guess but everything else makes sense. I run on the RR's also. I run HT10 square. I would look at the rubber gasket if they have not been replaced. It is how the pads are pull back from the rotor when you release the pedal. Maybe a little grease where the pads rest on the carrier. I grease my pins before every event but the bushings are loose in the bore as well as the pins slide easily. I would look at this comment in attacking the issue.
when i jack up the car and try to spin the wheel there is always some resistance and the pads are always sticking but I thought this was normal to have some resistance. I don't think the front wheels go a full rotation when I try to spin them when they are up in the air. Could this be it? ******************
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My thinking is the pads are dragging, this would cause excess heat, would be helped by you use of a better fluid, but the rotor is not allowed to cool due to the dragging where the rotor should be dissipating heat. If it was my car this would be my thinking. If you choose not to mess with the calipers borrow a infra red or let me know and I will send you mine to use and gather data.
ME:"I want to make my car faster and lighter"
THEM:" Get out and let someone else drive"
???
One pin per side will be easy to install, due to dimensional tolerance the second pin each side will be tight, which means your caliper cannot slide freely as intended. IF this is the case, you need to hone the bushings to provide the extra clearance required, so that the caliper floats. It is not enough that off the Spindle the pin sides freely thru the bushing.
Pins are silver color, bushings are gold. Caliper with bushings installed should slide freely on pins installed in thru caliper into caliper bracket.
https://c1552172.ssl.cf0.rackcdn.com/699860_x800.jpg
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Last edited by bluptgm3; 07-10-2018 at 12:10 AM.
Humor us. Put the old pins back in for the next event and see if it goes away. If it does not then more likely it is internal to the caliper.
ME:"I want to make my car faster and lighter"
THEM:" Get out and let someone else drive"
The reason I went with these pins is that I wanted to eliminate the "uneven wearing of pads" by upgrading the pins. The rotor warping was there long before I changed the pins. The calipers have never been rebuilt so I have a feeling that is probably it. I was told its normal to have some resistance when trying to rotate the wheel when the car is jacked up. I just don't know how much resistance is normal and what amount is abnormal.
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Yes i lubed up the bushing and the pin. I read that the bushing should be a very snug fit and a loose bushing was not a good thing.
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The reason I don't think it's a bushing / pin problem is that the warping of the rotors was there before and after I did this change. It still might be a problem with the calipers though not having been rebuilt in over 20 years (130,000 miles).
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I guess I don't know how much dragging is normal and how much is not.
Well I don't know anyone that has the warping issues you say you have. I would look into the caliper or at least the heat you are putting out as what you have is not normal. Do you get any knockback? If not start with the caliper.
ME:"I want to make my car faster and lighter"
THEM:" Get out and let someone else drive"
I haven't felt any knockback but the brake pedal has always had a pretty bad / squishy feel so I think it would be a little harder to tell than with other cars. I am going to rebuild the calipers. Do you have any suggestions on who makes a good rebuilt kit? I have also seen that some kits come with pistons so would that be a good start?
I would also like to say that when I brake the car does not pull in any direction.
Last edited by BeeHemDoubleU; 07-09-2018 at 10:16 PM.
The piston usually can be cleaned. If the caliper is functioning properly it does not hit the caliper. It rides on the square cut o ring. It is the square cut that pulls the pad off the rotor when it roll back into the groove. It is a wear item but often neglected. Not hard to do and you should be able to do in an afternoon even with a couple of coll beers included.
ME:"I want to make my car faster and lighter"
THEM:" Get out and let someone else drive"
Centric offers chrome plated replacement pistons if yours are badly pitted.
https://www.fcpeuro.com/products/bmw...vD_BwE#fitment
BimmerWorld offers Stainless Steel replacement piston option.
http://www.bimmerworld.com/Brakes/Ca...Set-Ate10.html
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Last edited by bluptgm3; 07-10-2018 at 12:24 AM.
Replace those calipers, don't attempt to rebuild yourself,
purchase quality rebuilds by WBR!
Look here:https://www.carid.com/search/1995-m3...nt-Brake-Parts
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