Jeff01SS

I just replaced all four rotors and pads on my 2001 SS. It has 30,000 miles. I used Autozone pads and rotors. My problem is that the rear brakes seem to be doing most of the stopping. I can feel the rear rotors after a hard stop and they are hot, but the fronts are only warm. Also, I get brake fade and my low traction light will come on when using them hard at speeds above 50. I don't think they're sticking because the rotors stay relatively cool while driving and just using light stops. I first noticed this problem after I changed out the front rotors. I did the fronts first, drove for a couple weeks and then did the rears.
Any idea of what could be wrong? Is there some adjustment to proportion the braking front to rear?

Midnight F-117A

The front/rear braking bias is automatically controlled by the ABS unit, it's called the EDC I believe (if memory serves me right)

I have no idea why yours are doing that but it doesn't sound normal. Most braking is done in the front normally.

JackZ28

I agree. The front brakes usually warp or crack before the rears. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> That is odd.

trackbird

iTrader: (4)

Remember, the rear brakes have less rotor mass and area, and may build heat quicker and retain it longer (less surface area to dissapate heat). Just a theory (much depends on the time since the last stop, etc). I dont think this is the actual answer, but I thought I'd throw it our for "brain food" and see what turns up. Better yet, I may go dig my Raytec infared thermometer out of my closet and pull out front and make 1 or 2 stops from 20 mph and take a quick temp reading on my car (a little research in the name of science?). If I get outside a play, I'll post my results in a little while. FYI I am running stock replacement Brembo rotors on the front, stock rears (all non slotted and non crossdrilled) and Carbotech panther plus pads on all corners (but the stock brake bias has not changed).

WJ SOM SS

iTrader: (11)

Usually it's 70% front--30% rear, but someone correct me if I'm mistaken... WJ.

trackbird

iTrader: (4)

Ok....the research is done (in the most scientific fashon available at 2am).

I took my raytek infared (non contact) thermometer and my camaro out to play. The car had been parked for 8 hrs in a 50 degree garage, and it is 30 degrees outside right now. I made a set of back to back stops from 60 and saw 100 degrees front and 90 degrees rear (as soon as we could dvie out of the car to measure). We grabbed a snack at the drive through and made a series of moderate stops on the way home and put it in the garage (53 degrees in the garage). Results below:

front......rear
183........147 as soon as I parked it
159........139 about 1 minute later
156........135 about 2 minutes after parking
155........131 about 2.5 to 3min.after parked
143........118 about 4.5 to 5 min.after parked

It seems that the back brakes will remain cooler than the fronts even during cool down in a wind free garage.

Did you change all the pads on the car and are they the same type of pad (brand and series?). If not, you may have a high temp pad on the rear and the fronts may be fading (and not making as much heat) and that may explain the differential (if the rears start 200 degrees hotter than the fronts, they will probably stay hotter longer...etc). Hope this helps.

trackbird

iTrader: (4)

Also, make sure your parking brake cables are not sticking or adjusted too tight. Just a thought.

Jeff01SS

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by trackbird:
<strong>Also, make sure your parking brake cables are not sticking or adjusted too tight. Just a thought.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The parking brakes seem to be just fine. There is no difference before and after changing the rotors. Nothing is sticking because the rotors don't get hot unless I do a couple hard stops.

Thanks.

Jeff01SS

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by trackbird:
<strong>Remember, the rear brakes have less rotor mass and area, and may build heat quicker and retain it longer (less surface area to dissapate heat). Just a theory (much depends on the time since the last stop, etc). I dont think this is the actual answer, but I thought I'd throw it our for "brain food" and see what turns up. Better yet, I may go dig my Raytec infared thermometer out of my closet and pull out front and make 1 or 2 stops from 20 mph and take a quick temp reading on my car (a little research in the name of science?). If I get outside a play, I'll post my results in a little while. FYI I am running stock replacement Brembo rotors on the front, stock rears (all non slotted and non crossdrilled) and Carbotech panther plus pads on all corners (but the stock brake bias has not changed).</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thanks for your replies. Even doing normal stops, the rears get much warmer than the fronts. When doing a hard stop from above 50 or so, initially I get good braking, then I'll get the low-trac light when the ABS kicks in, then I get brake fade. When I checked the rotors, the rears were very hot, I could even smell them. The fronts were just warm. I never experienced this until I changed the front rotors and pads out.

Jeff01SS

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by trackbird:
<strong>Ok....the research is done (in the most scientific fashon available at 2am).

I took my raytek infared (non contact) thermometer and my camaro out to play. The car had been parked for 8 hrs in a 50 degree garage, and it is 30 degrees outside right now. I made a set of back to back stops from 60 and saw 100 degrees front and 90 degrees rear (as soon as we could dvie out of the car to measure). We grabbed a snack at the drive through and made a series of moderate stops on the way home and put it in the garage (53 degrees in the garage). Results below:

front......rear
183........147 as soon as I parked it
159........139 about 1 minute later
156........135 about 2 minutes after parking
155........131 about 2.5 to 3min.after parked
143........118 about 4.5 to 5 min.after parked

It seems that the back brakes will remain cooler than the fronts even during cool down in a wind free garage.

Did you change all the pads on the car and are they the same type of pad (brand and series?). If not, you may have a high temp pad on the rear and the fronts may be fading (and not making as much heat) and that may explain the differential (if the rears start 200 degrees hotter than the fronts, they will probably stay hotter longer...etc). Hope this helps.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yes, all the pads were changed, and I think they were of the same type, but I'll check that out. I'm in no way a brake expert, but would think that if the fade was coming from the front, that they would be hot. I followed the instructions on the install.university link and didn't have any problems in changing them out. Was I supposed to open any bleeder valves or anything? That wasn't mentioned so I didn't mess with it. The pedal feels just fine--no sponginess or anything like that. It feels just like it should.

Thanks again for all the info.

Tom L. Busby

Hard to tell, but the back brakes sound like they are sticking. Assuming your parking brake is ok (set the parking brake while driving at 5 mph in reverse -- is it normal or what?): (1) The calipers need to slide on well greased pins, so you could take the calipers off, clean and re-grease the guide pins with some synthetic grease.
(2) The caliper pistons need to retract and yet the primary force to retract is supplied by the rubber seals inside the piston bore. This is very little force and is easily impeded. Is the inside of the piston bore all rusty? Are the rubber seals torn? Has the car been driven through deep water and the bores are rusted?

When you are reinstalling the calipers, clean and loctite the caliper-to-bracket bolts

trackbird

iTrader: (4)

Hey Jeff, you are only in Dayton, if you still are having trouble with your brakes, drop me a line and come to Columbus one weekend and we'll take a look at them (it's not that far away, and I'm on the west side of columbus). trackbird@columbus.rr.com

I am starting to suspect a possible caliper problem, but it's hard to tell from here. My thought about front pad fade...When a pad gets hot and starts to fade, it's friction level (coefficient of friction) is reduced, less friction means less heat, the more the fronts fade, the less they are still working (and therefore heating the rotor) while the back brakes are still trying to stop the car (and therefore building heat) and you could see a differential in temps that way.

Jeff01SS

Thanks for the offer, I appreciate that. Your explanation makes sense. I'm going to do some more checking around.

Jeff

Boo Yeah

here is how you tell....
get in a parking lot a big one.....
Turn and slam on the brakes at the same time....
if the front end dips and tries to understeer your front did more braking.....
if the car tries to oversteer or the front does not dip very much then your rear did more braking....
On most of the stock cars we set up we have to test and make sure that when we control the individual brakes are working with different grips(for a little advantage) so we test like that