02TL-osh

I have a problem with front rotors warping (a couple of sets now). I suspected either front calipers are binding or the rear brakes are not doing its share. Well I had the front rotors turned, put new pads in, and bled the brakeline. Here are my question: 1) are the pads suppose to be able to slide freely in the metal retainer clips? 2) After pressing the brake pedal to seat the new pads, the pads grabbed onto the rotor. How freely should I be able to turn the wheel after releasing the pdeal? I felt some resistence between the rotors and the pads, is that normal? 3) after seating the pads, the caliper slider pin no longer slides (since the caliper "pulls" in tight). Is that normal?
In summary, if anyone can tell me how to tell if calipers are functioning correctly, I'd greatly appreciate. Thanks!

01tl4tl

what bleed order did you use?
Are you on stock rotors- those warp- and when you resurface them it removes thickness and they warp again

Have you read the brake DIYs- there are a few here
when the brakes are off- there is about 1 mm clearance from pad to rotor

the rear brakes only do 30 percent of the work
Many of us are at a time/miles where the calipers are wearing out from use and need to be replaced
Often 1 side will stick partially on or you will feel a drag when braking

A great upgrade is calipers for a 1995 Legend LS-C , they are the same price as rebuilt tl calipers and are dual piston for way better braking

at this point- you really need someone who has done brakes to look at your car and see whats going on

01tl4tl

no mention of brake caliper grease is in the OPs description of work performed
Was the proper grease used on contact and slider areas??

swalch@stanford.edu

It sounds like the front calipers are binding. After seating the pads, if you turn the rotor by hand, it should have some resistance to turning and make a uniform sound as the pad surface slides along the rotors. This is a pretty sensitive test of runout. The pads should move freely in the clips. There should be disk brake grease on all metal to metal contact points, including the backs of the pads and the caliper slider pins. I would recommend trying rebuilt calipers.

02TL-osh

Thanks for your quick reply. I did hear some noise as I turned the rotors around, as they glided through the pads. I guess I was not sure how freely the pads should move in the retainer clips. Here is the list of things I have done, perhaps that would give you a complete story:

1) had front OE rotors resurfaced last year. steering vibration and pedal pulsation were gone for 4 months, then came back.
2) replaced front rotors to PowerSlot ones, and replaced the rear rotors with NAPA cheap ones. Also replaced both front and the back pads.
3) bled the line after doing the above.
4) The powerslot rotors held up for 4-5 months without vibration. I broke in the pads by going 45mph then braked hard to slow down to 10mph, then picked up the speed to 45 mph and repeat. Do this 6 times with cooling in between.
5) Now I just had my powerslot refurfaced last week and put in new pads in the front. I am replacing the rear rotors to ATE premium slot rotors from TireRack.com

The front rotor warping is driving my crazy on otherwise an excellent car.
I hate the vibration feel on the steering wheel. Any more info would be greatly appreciated.

Thanks.

02TL-osh

The order I bled was LF, RF, RR, and LR. Thanks.

swalch@stanford.edu

It seems like your front brakes are wearing out way too fast. I would try a set of rebuilt calipers. They go for as little as $60 each exchange. If they are binding the brakes will heat up and warp the rotors. I understand the slotted rotors are better in terms of warping, but you shouldn't have this much trouble, unless you use the brakes awfully hard.

fsttyms1

I agree. Sounds like calipers are bad. Also resurfacing rotors just makes them thinner and heat up faster causing more warping. Especially if you have a caliper hanging up.

01tl4tl

your pad bedding procedure was close,,, but not quite

The idea is to heat the pads all the way thru, and rotors up to a high temp- by doing some instantly repeated 45-10 mph medium to firm intensity slow downs to get it all nice and toasty
then do a transfer layer of material to the rotors with 2 or 3, 60-30mph medium effort slows
then the freeway cruise cool off drive-

By letting it cool between each application of brakes,as I think you did,
all you did was heat shock them several times, and probably glazed the pads - no sweat.

New pads often release have glue and resins outgassing the first time, maybe a few times when brand new

When you feel the brake pedal get soft during the warm up runs, and smell brake pads- thats time to do the transfer layer with 3 medium slow downs-
it literally bonds pad material to the rotor face- so when you apply the brakes- its same to same material contact = much better rotor and pad life and braking ability!!

try MrHeelToes method- its pretty good for fixing problems
http://heeltoeauto.com/httech/YaBB.pl?num=1184261899
Note- disclaimer
observe all local speed laws- it may say 80 but 70 is fine~

Make sure to do an after drive- cooling off --drive on freeway cruising speed-
NO use of brakes-15 minutes, to let it all temper correctly
May need to repeat a few times to get it solid stopping

You knew the bleed order- excellent!! makes it easier to help you, knowing you did read up first!

There is very little motion when assembled- but its there if you try hard

To test a caliper operation-
remove it and place a small piece of 2x4 wood in sideways(thin)in the caliper
have trusted friend slowly and gently depress brake pedal as you watch the piston extend- any rust or bad looking stuff on the sides of the piston- thats whats important

push the piston back in- use the 2x4 and a c-clamp or the real $5 brake tool-or the wood and open the bleeder valve
Pushing the piston in perfectly straight is critical!! get it crooked at all,,, and tear the oring seal inside- now you have to get a rebuild kit for 20 bucks

have friend push pedal again- yada
do this a few times to cycle the brake pistons

Now do the other side, same thing
Then Rebleed the brakes- its only 10 minute job now that you have practiced it ~

Hi performance brake calipers like brembo- you are supposed to do that cycling once a year and flush the fluid- the pistons usually get such little movement range-

As the pads get thinner, the piston moves in farther to compensate and keep the distance to the pad the same-
this cycling keeps them operational for full thickness new pads to work when you install them too

smartypants

Hi O2 :

During a routine brake maintenance I was told by a mechanic that my RR caliper was seized and needed to be replaced. I was skeptical until I started going through pads on that one caliper, usually with excesive wear on one pad. I replaced the pads myself, making sure everthing was free and well lubricated, including the brake piston. I was still not convinced until I went on a 3 hour drive and started smelling burning break pad. (it has a unique acrid smell) When I stopped the car, I got out of the car and checked each wheel and saw wisps of smoke coming out....wait for it....of the RR wheel. I changed the caliper and it has been fine ever since. Interestingly, the caliper piston was definately siezed as it would not budge. I used a rebuilt unit as it was the most economical solution...still a $150 bucks !

So look for any of the symptoms I experienced and you should be able to tell if the caliper is bad.

smartypants.

01tl4tl

thats what you get for not listening to your mechanic!
when in doubt, get a second opinion- dont just stick parts on it several times!!!
the uneven pad wear inner to outer pad is a techs first signal that something is wrong!

You could have caught fire in the tire and the wheel-
ever seen a magnesium fire? they are bitchin!!

02TL-osh

I tried to look for those symptoms of binding front calipers, but found:

1) inner and outer pads wear fairly evenly. In fact not much wear at all since I installed them new 10K ago
2) no smell of burning pads
3) I can push the pistons in with a C-clamp and a thin metal bar (cross the entire piston surface).

For a normal driving situation, are the pistons supposed to go back into its rubber boot themselves after I release the brake pedal? When the battery was disconnected and wheels were off, they stayed after being pushed out by the brake pedal during pads seating procedure.
Well, I probably will try a new pair of front calipers after changing the rear rotors and pads (which I wanted to change anyway).

Thanks to all of you for your advices.

01tl4tl

Stop changing parts and let a specialized brake shop take a look!
Its diagnosis is cheaper than the next things you will go out and buy

The caliper piston does not retract to the boot/flush-EVER_
DONT do it when putting new pads in - doesnt need all that room anyway

they only back off about 1 MILLIMETER- a few hairs away- from the pads when off, so when you hit the pedal - you have brakes!
Just becasue you can push the piston IN does not mean its working right
Open the bleeder valve and see if you can compress it smoothly with the bar and hand power- and watch it extend
Do the test I suggested-the 2x4 will keep the piston from coming out too far

I dont make this stuff up~ its the shop methods of seeing what parts are needed

02TL-osh

Thanks, I will let a mechanic check it out.

thinhthan

is the 94 legend L the same upgrade?