Driving home from work, an suv in front of me and a car in front of him, left lane of the freeway. In the right lane, a semi. The suv cuts to the right and goes around the car in front of him that is driving slower than the speed limit, we're doing about 70. I judge this and I have enough room and time to speed up and do the same in front of the semi. As I hit 75 the car that was moving slow is now really moving slow and then jams on his brakes, attempting to turn onto the roughly paved off limits u-turn things that are there for the police to use when pursuing someone.

So this guys car is small, and it slows down really fast. I STAND on my brakes and folks, it's not happening. Looks like I'm about to get that new CS front bumper I've always wanted. This car is just not stopping, period. The only reason I didn't hit him is because he changed his mind (or saw that black Mustang closing in on his rear view mirror in a hurry) and let off the brakes and kept going.

I replaced the rear pads and turned the rotors at 75K miles. I didn't do the fronts, because they didn't need to be changed, had lots of pad life left. I thought that was weird, but hey, maybe I got super pads from the assembly line. Fast forward to today, nearly pee'd my leg, 108K miles, and ummm, as you can see by the pictures, a lot of pad left on the fronts. What gives?

Is there something wrong with the pressure that's being applied to the fronts? Is this a caliper issue that I should rectify by replacing the fronts, or is there something else that should be fixed? I'm obviously looking at new front rotors, pads and now SS brake lines. But given the amount of pad still left here, I'm wondering if those things aren't the real issue here. Would really appreciate your thoughts on this, especially from the track guys who go through brakes A LOT more than I do.

Thanks everyone!

 

Have you ever looked at the surface of the pads? They could be glazed. I'm also willing to bet your fluid is pretty gross at 100k+ miles, unless you did a flush at same time as the rears.

This is a good time for an upgrade! I just did Powerslot/Hawk HP Plus(because i'm crazy) along with SS lines all around and Super Blue fluid. If you're not racing i'd say get some Hawk Ceramics and enjoy quiet brakes.

 

One question- were the brakes not grabbing, or were the tires sliding? What shape are your tires in also?

Try doing the brake-bedding procedure, and see if the braking improves during/after that. Then get the fluid flushed completely.

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

If you don't want to do a full brake upgrade, I'd at least get the front rotors turned, replace the pads and get the fluid flushed. After all that's done, be sure to do a proper brake bedding and immediately check to see if all 4 brakes have a good amount of heat coming off. The bedding procedure will also demonstrate if everything is working properly again. (Make sure your seat belt is on tight!)

 

Yep need to answer was it brakes or tires... did you slide? ABS kick in?

 

No tire skids, ABS kicked in, etc. The car was trying to slow down, it just wouldn't. The front rotors are definitely warped as well, shakes pretty good when braking, which started fairly recently.

When I replaced the rear pads before, they were completely worn down, and the fronts looked pretty much like they do in the picture above. Really no change since then either. When I replaced the rear pads we pumped the brakes and opened the lines to "flush" out as much dirty brake fluid as possible. Kept adding new until we got it to come out clear through the rears, but obviously not the fronts, so it's not all brand new brake fluid. And what was replaced is now at 30K miles as well.

Also, the tires are fairly new. They've been on the car a little over a year now, a LOT of tread left on them.

 

ABS kicking in means the brakes apply hard enough to lock the tires, so its a tire issue. Thats not to say upgrade pad, clean rotors & flushed fluid is not a good idea though.

 

Ummm, am I crazy. Doesn't ABS stand for Antilock Braking System? I don't understand how tires with less than 15K miles on them slowing down from 70+ mph would be the factor over brakes with 108K miles on them? Relatively speaking, the tires are new, the brakes are old. You sound convinced, I'm not trying to argue, I just completely don't understand what you mean by "it's a tire issue".

 

Rule #1 in the Automotive world.
Your front brakes do MOST of the stopping! Period. If your rear brakes wear out Before your fronts do, you have a serious brake problem. Your front end should have bottomed out with that kind of brakeing at speed, if it did not at speed, your front brakes are NOT working properly. Replace the .....
1.) FLUID!
2.) Calipers
3.) pads
4.) Rotors

And live long and prosper.

 

Well, in general abs kicks in because a wheel stops rotating which means the tire has lost the friction of the road to keep spinning (sliding). This means the clamping force of your brakes > your traction.

Now back up a bit because I may have been too quick on that generalization, you may have felt ABS for the rear brakes if you really stood the car on its nose, pushing all weight on the front/unloading the rear which makes the rears more likely to lock while the fronts are not

His rears might if he drives aggressively with the traction control on.

And I wouldnt jump to replacing calipers, quite a few guys run tracks with GT calipers... now you should check none are frozen, are all pads worn evenly? How are the slides?

I upgraded to GT500 brembo's with stainless lines, ATE superblue fluid because..well I wanted to, need to get rid of these factory pads though (only temporary)

 

My first thought was glazed front pads.

 

My first thought was change your underwear.

 

Well I've got 2 choices. OEM size cross drilled and slotted rotors, pads and SS lines front and rear vs. 14" cross drilled and slotted front rotors, Brembo 4 piston calipers for the fronts, OEM size cross drilled and slotted rear rotors, pads and SS lines all around. The set with the calipers is 3x the price as well.

I have Shelby Razor 20" wheels, so the stock size rotors do look a bit small there. So what would you do? 3x the price and get rotors that fit in the wheels better, new calipers, etc. or save the $ and still get a tremendous upgrade over stock?

No, I don't track the car currently, however I'm never selling it. Someday it will get a supercharger, but that could be 5+ years down the road, who knows. That will likely go on during the engine rebuild, which I won't do probably until 150K+ miles, or another 3 years minimum.

Clearly I'm not a brake guy, so just to be clear, I cannot use my stock calipers on 14" rotors correct? If I want to go bigger, I HAVE to replace the calipers?

 

A common misconception about brakes is that you can 'warp' rotors. In all reality, it's **** near impossible to warp rotors under typical use, unless you've got a semi-sized vehicle on Kia-sized rotors.

What DOES happen is that when your brakes get hot and you stop the car, pad material (especially from cheap OEM pads) can build up on the surface of the rotor. After many cycles of this, you get high spots, which make it FEEL as though the rotor is warped.

The best way to avoid this is to properly season your rotors when they're new (http://www.baer.com/index.php?option...ation&Itemid=4), then bed your pads correctly (http://www.baer.com/index.php?option...ation&Itemid=4). These procedures will make your brakes last longer and work better than if you did not do them. My dad lives on a LONG rural road that allows me plenty of space to do the procedure, and if I ever get a shake in the wheel that I think is from pad buildup, I'll head to his place and re-bed the pads. It'll knock off all the pad buildup and get things right as rain.

As for your front calipers not clamping more than the rear, I think you might have stuck slider pins or seized calipers. You'll usually go through two sets of front pads in the time that it takes to go through one set of rear pads.

JR

 

Thank You godspunk32.
It's nice to be vindicated.
You can get new takeoffs for a heck of a lot cheaper than getting bigger calipers/rotors and pads. Also know that once you do that, you are limited as to what size wheel you can put on the Mustang forever (or until you swap back).
Just sayin...............

 

probably your calipers, had same problem on a 4wd years ago, rebuilt them myself, but easier to buy new or rebuilt with exchange. also flush your lines, or buy new bigger front brakes, make sure your wheels will clear going bigger.

 

I ended up ordering new cross drilled and slotted rotors from RotorPros for both front and rear, OEM size. They come with pads for the stock calipers front and rear as well. I went ahead and sprung for new stainless steel brake lines on all 4 corners too. I still have to purchase brake fluid, I will likely purchase some OEM quality fluid unless anyone feels it wouldn't be worth it to use the SuperBlue that I hear so much about.

I'm excited to get these installed, but not looking forward to working in my ultra hot garage while it's still 110 degrees outside.

 

SuperBlue is great. Its currently what i'm running, but to be honest if you're just going to DD the car, save the money.

 

Agreed. Valvoline's DOT3/4 fluid is good up to like 500 degrees, which you won't get near with street driving, unless you're really bombing some southern California canyon roads.

As for the slotted/cross-drilled rotors, be aware that the slots are going to wipe your pads off at every pass, and will significantly decrease your pad life. Also, I've seen a lot of people buy cheap drilled rotors that develop cracks over time. One way or the other, please, please, please make sure that you follow the seasoning/bedding procedures that I posted earlier.

JR

 

I will most definitely bed the brakes properly, thanks very much for posting those instructions.

At this point, I could care less about ripping through pads quickly, I want to be able to stop without question. $50-$200 a year on pads is nothing compared to rear ending someone at 50+ mph. Besides, I made it 108K on the stock front pads, so my I'm already way ahead on the ROI scale for brake pads.