What else is holding my brake pads in?

Z06C5R · 06-16-2008, 06:18 PM

Let me just get my facts straight before I resume the struggle with my brakes tomorrow afternoon:

The only thing holding the pads in besides pressure from the piston are the retaining pins, right? I compressed the piston a bit and had a good bit of side-side wiggle going on the inside pad, but it wouldn't come out at all! It almost looked as if the pad was wider than the edge of the caliper where it should slide out...?

Please tell me I don't have to take the calipers off to change my pads - that would just be stupid.

hpservertech · 06-16-2008, 08:29 PM

Well, they could of worn a groove on the rotor, causing them not to pull up. Much easier to pull the caliper though. 5 minutes if that much to get them off.

flash968 · 06-17-2008, 06:05 AM

if it is like the 968, there are spring clips bonded to the back of the pad that fit into the cups of the pistons

but yes, commonly the rotors are worn to the point where the pad is beneath the edge - if this is the case, you need new rotors, as they are now beyond the wear limit

looneybin · 06-17-2008, 08:01 AM

you do need to take the caliper off of the rotor to remove the pads, but you dont need to totally remove the caliper from the car, just pull it back off the rotor once you have the pins removed, then the pads will come off.
There are metal spring clips that help to hold the pads in place.
dont let the caliper hang from the brake line, you could damage it, use a coat hanger to suspend it from the coil spring

Cking1975 · 06-17-2008, 09:59 AM

I found out the hard way, if the brake system (rotors, calipers, pads, etc) are shot, it is better to replace all of it. Or at least rebuild the calipers and get a new set of rotors...if things do not come apart fairly easy, then there is something wrong.

DSPTurtle · 06-17-2008, 10:21 AM

No way do you need to remove the caliper. Just take the metal spring locking element out of the pin holes. Then remove one of the pins while holding the spring clip down. After you remove the first pin the spring clip should easily come out. Pull out the second pin. You will need to push the piston pretty far back into the caliper to disengage the outer pad from the backing nub. The piston will move back in, you just need a decent flathead screwdriver to wedge between the pad and the rotor. I am talking 1/2 to 1" of free play on one side or the other. Wiggle the pad out of the caliper. If your pads are really worn you will have to compress the piston quite a bit. Watch out for brake fluid coming out of the reservoir... especially if you have topped it up since the pads wear worn.

looneybin · 06-17-2008, 12:41 PM

Quote:

Originally Posted by DSPTurtle

you just need a decent flathead screwdriver to wedge between the pad and the rotor

You're kidding, right

good luck with that

Z06C5R · 06-17-2008, 12:42 PM

Yeah, I was figuring I might need more play, but those damn calipers are hard to spread! I was about to snap the fairly substantial flathead screw driver I was using, and I only got a couple mils of free play!

I'm gona go try again right now with a heavier prying apparatus... If that won't work, then it might become necessary to pull the calipers.

looneybin · 06-17-2008, 12:46 PM

STOP!!!!!
don't pry against the rotor.
Take the caliper off & use a c-clamp to push the piston in

DSPTurtle · 06-17-2008, 02:46 PM

Thanks for the well wished looneybin... I can always use good, positive thoughts

Hmm... I have had the pads in and out many, many times and have not had a problem (knock on wood, probably next time I will totally ruin something). Be careful which way you pry. And do it gently!!! Make sure the tip of the screwdriver is biting into the pad (you are replacing those anyway). There also is a center slot in the pad that allows you to get the prying device down further into the recess so you can get a much better leverage angle. You want the point of the prying device as close to the center of the piston as possible. It really should not take to much to push the piston back into the caliper. Unless you cock the piston it shoudl move consistently with firm pressure.
Or, you could remove the two 19mm mounting bolts on the back side of the caliper and try to PRY the whole thing off the rotor... especially if the rotor has an outer grove. So in my view, either way you are prying on something and since the pad is what you are trying to replace it is no biggie. Unless you are replacing the rotor too... then pry that biatch and let us all know if it really makes a scratch or not

Z06C5R · 06-17-2008, 03:58 PM

Well, I got em with a heftier flat-tip and a pry-bay. I made sure I was either pointing the tip into the pad, or when I couldn't, I made sure I was prying against either the hub or the lower part of the rotor where no brake-pads contact it. Seems to have kept the rotors in shape.

BUT, now my brakes are mush, despite extensive bleeding, YAY!!! What a fun car to work on!!! Ah well, it's worn me out for today... I'm gona go back and flush / bleed the entire system tomorrow and see if that helps.

DSPTurtle · 06-17-2008, 05:02 PM

Hmm... that is odd. Usually after replacing pads all I have to do is pump the pedal 4 or 5 times and they are back to hard as a rock. Did you happen to notice the level of the brake fluid at any point? Because the new pads are thicker (so the piston sits further in the bore) you shoudl not have had to do anything with the fluid level... ASSUMING YOU DID NOT CRACK OPEN THE BLEEDER OR ANY BRAKE LINES. (not yelling, just for emphasis before I get flamed)
It is possible that the fluid in the caliper was old and pushing it back up the line moved some crud around. Too late to tell now since you stated that you are bleeding them already anyway. Brakes are finicky. I hate the feeling on my hands after I bleed brakes with fluid all over them. Plus I can only get my official pedal pumper to do it about every six months... she hates that job

Glad you were able to get it done though. Hopefully you remembered to grease the pins and the spring clip

hpservertech · 06-17-2008, 05:43 PM

You dont have to bleed the brakes when doing the pads or rotors. Every car is like this.

Why did you bleed them?

Z06C5R · 06-18-2008, 12:39 PM

I did open the bleeders - it's the only way I could get the things spread apart without use of EXTREME force. So of course I most likely got air into the system, and therefore I did a standard brake bleed. It should have been more than enough to get any air out of the system at the caliper level, but apparently not.

flash968 · 06-18-2008, 12:59 PM

unless they have been bled recently, they should be bled - in fact, they are supposed to be completely flushed and bled every 2 years maximum

i do not recommend pad slaps - if the rotors show ANY wear, at least get them turned - measure them for thickness and replace if they are down to the spec

Z06C5R · 06-18-2008, 02:58 PM

What are the specs for the rotors... I was wondering that while I was doing the pad change.

hpservertech · 06-18-2008, 03:17 PM

Using C Clamps makes this so much easier. Best tip is to open the master resivour when you try to open them. Have done this on dozens of cars and never had to bleed brakes when changing pads/rotors.

Here are the specs for the brakes: http://www.clarks-garage.com/shop-manual/brake-04.htm