Replaced Caliper - Shrieking Brake

[mikewags]

I replaced my front right brake caliper a few weeks ago. It went rather well, easy install; saved some money doing it myself...

Anyways, since then that brake has been making a high pitched shrieking sound when I approach a stop. If i brake harder, it will subside; but the slow easing into the brake causes the shriek. It's really annoying.

Any ideas what has caused this? I reused the brakepads in the old caliper; and haven't changed the front left caliper (it hasnt given me any problems). My buddy said machining the disc might help; although I'm not sure if this is neccesary? Might new pads fix it?

FYI - the old caliper was aligned incorrectly and rubbing the disc; this is why i replaced it.

http://www.trustmymechanic.com/htmlmessage9.html

[zbane]

If the pads still have plenty of life in them, you might try going to the auto parts store and getting yourself some of that brake squeal stuff. If the pads are getting low, it may be a function of the pad letting you know it's about time to change them. Of course, if you do change out the squealing pads, be sure to change the other side as well (if not at all four corners).

[Arne]

Brake squeal is high-frequency vibration. The pads are moving in the new caliper. My luck with the goop you put on the back of the pad has been terrible over the years. All it seems to do is quiet it for a short time, and make a mess of the back side of the pad.

First, make certain you correctly re-installed all of the shims and tension springs. Instead of the thick goo, I use a good synthetic brake grease on the pad backing plate. A very thin smear on the back side where the piston touches, and on the edges of the pad backing plate where ever there is evidence of metal-to-metal contact (i.e. polished spots).

[bigoak]

make certain you correctly re-installed all of the shims and tension springs.

This is what jumps immediately to mind. You may have either forgotten to re-install the shims or installed them backwards (they are directional...).

Might want to throw new pads in there if the orginals are wonky at all.

Good luck.

[mikewags]

Maybe i installed the shims backwards. I will take it apart again tomorrow and reassemble to see if that makes any difference.

Thanks guys.

[Oiluj]

Also, verify the pads are clean. If not, spray them liberally with brakeclean and "very lightly" scuff them up with fine emery paper. Do it outside and don't breathe the dust.

[srbigbutt]

Mine squealed pretty bad and when I checked them they didn't have any shims. Ordered some from BlackDragon and they havent squealed so yet.

[doradox]

I replaced my front right brake caliper a few weeks ago. It went rather well, easy install; saved some money doing it myself...

Anyways, since then that brake has been making a high pitched shrieking sound when I approach a stop. If i brake harder, it will subside; but the slow easing into the brake causes the shriek. It's really annoying.

Any ideas what has caused this? I reused the brakepads in the old caliper; and haven't changed the front left caliper (it hasnt given me any problems). My buddy said machining the disc might help; although I'm not sure if this is neccesary? Might new pads fix it?

FYI - the old caliper was aligned incorrectly and rubbing the disc; this is why i replaced it.

http://www.trustmymechanic.com/htmlmessage9.html

If, as you said, the old caliper was misaligned then chances are the pads you reused are unevenly worn. This can cause your noise too. Otherwise Arne's suggestions should solve your squeal.

Steve

[mikewags]

Unevenness of the pads is most likely it.

The shims are a backplate to the pads right? The only thing I really did was take the pads from the old caliper, pop them into the new one; and secure them with the clips. I'll have to double check if there are any shims.

Edited August 24, 2008 by mikewags

[bigoak]

The shims are a backplate to the pads right? The only thing I really did was take the pads from the old caliper, pop them into the new one; and secure them with the clips. I'll have to double check if there are any shims.

Yes. See part #2 in the photo below from the Black Dragon catalog.

If they're not in, it would cause your problem.

[DeesZ]

The brake shims from Nissan look like the attached picture. Some people swear that this is the best to use. There is a left and right for each caliper; four used for a complete job. Nissan dealer can provide them for a bit over $2.00 each IIRC.

Attached photo is of a right shim.

[mikewags]

***UPDATE***

Shims were there...I ended up taking off the rotor, getting it machined for $7.00. I then bought new brake pads for the front of the car $22.00. After reinstallation, all is good; no more shrieking.

On a side note, i've bled the air out of the brakes; but I do notice some play in the brake. I will push down and there is no response from the brakes until about a 1/3 or so of the way down. Is this normal? Can this be characteristic of the drums being bad, or something else? Maybe i didn't get all the air out? Any helpful advice would be great.

Thanks!