jbauch357

So after taking my car on the full road course I have had a pretty squishy brake pedal.

First problem was boiled fluid - which I have resolved by flushing the entire system with Motul 600. This brought back quite a bit of my pedal firmness - but it was still considerably squishier than originally.

Second problem is pad taper - which I am in the middle of trying to resolve.

I removed the pads and rotors on every corner then buffed the glaze off the pads and roughed up the rotors. When re-installing the pads I swapped the inside with the outside. My thinking on this is that the thicker portion of the pad (less tapered) will now take more punishment than the lower side. This will slowly but surely get the pads to an even kilter before starting to taper in the opposite direction again.

After doing this, as expected I still have a squishy pedal - but it has gotten 10 times worse than before. On the first pump my brakes feel dangerously soft, and on the second they gain a bit of firmness. One reason is the pads aren't mated to the rotors since they are now on opposite sides and will take a little bit to break in. Also now that the pads are swapped I am pretty sure they aren't getting uniform pressure from front to back...

Has anybody else tried doing this to save a pair of pads with a lot of life left on them? I have a feeling all I am doing is wasting time before I break down and get some good street/track pads to put on all four corners...

Bill Dearborn

With the standard C5 pads I found that doing nothing but driving the car on the street would get them to recover a certain amount. It would take a couple of weeks but the pedal would slowly come up. However, I think you didn't really do what you thought you were doing. By swapping inside for outside what you are doing is just rotating the pads in space by 180 degrees. This leaves you with the thin spots in the same place just with the pads flipped. The only way to compensate is to swap left to right sides of the car. That way you will be forcing a new taper wear pattern onto the pads.

Bill

jbauch357

The taper that I saw was end to end (top to bottom as the pads sit in the caliper) so unless I'm mistaken, trading them from inside to outside would effectively flip them top to bottom and place the thick portion where the thin previously was.

This was a vain attempt at saving the pads since I need tires bad and don't wanna pony up for a full set of pads right now. But being that I have auto-x this weekend I may be over-nighting some pads in...

AU N EGL

May need new calipers. If the pad tapper is that noticble then not much you can do except replace the calipers.

This is something I do each winter, along with replacing each hub bearing.

jbauch357

what calipers would you recommend? are you going with OE replacements or aftermarket?

davidfarmer

the ONLY way to eliminate pad taper is to run calipers with different size pistons. Pad taper is caused because of the leverage of the rotor trying to rotate the pad.

The leading edge of the pad is "self energized". The rotor, sliding through the pads, trys to push the pad with it. This moment-arms rotation causes the leading edge to always apply slightly more force than the trailing edge.

In aftermarket 4 or 6 piston calipers, the leading pistons are smaller than the trailer pistons, to balance this. I can attest that the Stoptech calipers give virtually NO pad taper.

similarly, the outside edge of the pad will wear slightly more than the inside, due to the fact that the rotor is traveling faster there. This is usually not as prominant as the fore/aft taper.

You could attemp to reverse the pads on the street to reverse the wear pattern, but I think you'll just make matter worse.

Basically, you just need to get new pads when the differential is prominant enought. NO solution if you are using OEM calipers....sorry.


btw, drum brakes do the same thing. The shoe that is hinged so that is floats in the direction of rotation will wear less than the shoe that is rotating against the motion. Simple leverage.

jbauch357

well crap - sounds like it's caliper time for me...

what do you recommend for an affordable (I didn't want to say cheap) aftermarket caliper? do I need to install match sets on all four corners when I do this???

the car is a daily driver that gets flogged on the street and beaten even harder on regular track events...

davidfarmer

Stoptechs front only kit is affordable, but it is a full kit (rotors, calipers, lines etc). You also would need 18" front wheels if you aren't already running them. List on the front kit is $2395 (for a 4-piston C5 front), but myself (or others) can probably do a little better if you are interested.

There are other kits on the market. You need to be very carefull however, as many of the kits use off-the-shelf calipers that don't necessarily match the OEM piston area, and care really throw your brake bias off. Just ask the tough questions and make sure the system not only looks big, but can actually improve the cars performance.

I'm sure some other vendors/user will chime in, but I'm a Stoptech fan myself.

AU N EGL

Same PBR calipers. unless you get a BBK as David suggests.

Bill Dearborn

You are correct on that type of taper. All of my pads have tapered at an angle with the inside pad thick at one end and the outside pad thin at that end. At the other end it is just the opposite with the inside pad thin and the outside thick.

Bill

jbauch357

ah, now I get what you are saying. strange that you would have the inside and outside tapering on opposite ends. seems to me they would both taper on the same end? shows that I still have quite a bit to learn...

wtknght1

Stock calipers are cheap man...I can get them for about $105 all day long. I normally replace my front calipers 2-3 times a year; rear is once per year. As hard as we pound on them, taper will start and only get worse. For DE stuff, I'd say replace them once a year just as insurance and keep the old ones as a spare.

jbauch357

Really, where can I pick up a pair of stockers for that price? If the local dealer wants $110 just for a rotor I am sure they won't give me a caliper for the same price. Also the car has 46k on it, and as far as I know has never seen new calipers - so it's probably time...

Bill Dearborn

Have had the same type of tapering on both my 97 and 03. The 97 did it when I had 2K miles on the car. The brake pedal started going to the floor after the 2nd session at Watkins Glen and we bled the brakes several times to no avail while at the event. The next day the dealer checked the pads and replaced them at all 4 corners under warranty due to pad warping and the pedal was back where it was supposed to be. The next event the new pads did the same thing but I bought another set myself and installed them and the long pedal problem was gone again. Now I have sitting on the shelf plenty of sets of stock C5 pads, PFC pads, Hawk pads that have 2 to 5 days wear and a lot of taper.

Bill

jbauch357

so what do you do with all those tapered pads? if I had some sort of mill or planer I could straighten mine out - but since I don't I am planning on just upgrading pads for now and possibly calipers later...

jbauch357

Well....... nevermind the tapered pads. After flogging the car for a couple hours straight tonight (in attempt to even out the taper after swapping pads) I found that I created stress cracks throughout one of the front rotors. I was already on the verge of ordering, now it's official. Before the weekend there will be Hawk HP Plus pads and NAPA rotors on all corners. We'll see if those hold up a little better...