Subaru Brake Squeal

[webstericehockey]

Well, I've read up a lot on this subject and I'm getting mixed answers:

I have a 1995 Subaru Legacy Wagon with 4 Wheel Drive and ABS. A month
ago, the left disk brake brake started squealing. Its a really high
pitch squeal and only occurs when my foot is off the brake and occurs
regardless of speed (Ive had it squeal anywhere from low speed to
highway speed driving). When I apply the brake, the sound goes away.
Likewise, when i turn the wheel left or right, the squeal gets softer
or louder. Also, the squeal occurs randomly (drive to costco no
squealing but on the way back squealed badly). The squeal also
increases as the speed increases; say from 0-20 mph
squeak-squeak-squeak and at 40mph just sounds like one constant loud,
high pitched squeal.

Here's the maintenance Ive done:
-Brand new master cylinder, new brake rotor, new brake pads, and a new
brake caliper (all remanufactured)
-Applied disk brake anti-rattle but brakes still squealed, took wheel
off to inspect and noticed that the anti-rattle compound had gotten
onto the anti-rattle spring (anti-rattle is really sticky stuff), so I
completely cleaned off the pad and anti-rattle springs w/ denatured
alcohol and applied high-temp silicon brake lubricant on anti-rattle
spring (the part where the pad moves in and out) , but the squeal
actually got worse.

Here are a few things I've heard that solve this problem, but need
verification, please:
-Bad or failing hub bearing (I read that this makes more of a grinding
noise, not squealing)
-Dust cover/plate on back of rotor (Ive checked for contact, but I dont
see any)


As you can see, ive spent a lot of unnecessary time and money on this
project, and at this point have run out of ideas. ANY help or comments
would help TREMENDOUSLY. Thanks.

 

[Carl 1 Lucky Texan]

Well, I've read up a lot on this subject and I'm getting mixed answers:

I have a 1995 Subaru Legacy Wagon with 4 Wheel Drive and ABS. A month
ago, the left disk brake brake started squealing. Its a really high
pitch squeal and only occurs when my foot is off the brake and occurs
regardless of speed (Ive had it squeal anywhere from low speed to
highway speed driving). When I apply the brake, the sound goes away.
Likewise, when i turn the wheel left or right, the squeal gets softer
or louder. Also, the squeal occurs randomly (drive to costco no
squealing but on the way back squealed badly). The squeal also
increases as the speed increases; say from 0-20 mph
squeak-squeak-squeak and at 40mph just sounds like one constant loud,
high pitched squeal.

Here's the maintenance Ive done:
-Brand new master cylinder, new brake rotor, new brake pads, and a new
brake caliper (all remanufactured)
-Applied disk brake anti-rattle but brakes still squealed, took wheel
off to inspect and noticed that the anti-rattle compound had gotten
onto the anti-rattle spring (anti-rattle is really sticky stuff), so I
completely cleaned off the pad and anti-rattle springs w/ denatured
alcohol and applied high-temp silicon brake lubricant on anti-rattle
spring (the part where the pad moves in and out) , but the squeal
actually got worse.

Here are a few things I've heard that solve this problem, but need
verification, please:
-Bad or failing hub bearing (I read that this makes more of a grinding
noise, not squealing)
-Dust cover/plate on back of rotor (Ive checked for contact, but I dont
see any)


As you can see, ive spent a lot of unnecessary time and money on this
project, and at this point have run out of ideas. ANY help or comments
would help TREMENDOUSLY. Thanks.

Does it change much with sweeping turns left or right? Also, is the
temperature of one hub hotter than it's companion? You should also try
to SAFELY have someone pace the car, on foot or bicycle, in a parking
lot to see if they can hear anything from outside the car.

Carl

 

[webstericehockey]

Does it change much with sweeping turns left or right? Also, is the
temperature of one hub hotter than it's companion? You should also try
to SAFELY have someone pace the car, on foot or bicycle, in a parking
lot to see if they can hear anything from outside the car.

Carl

Yes, it does change with sweeping turns. Im not sure it the hub temp
issue, but i noticed an uneven wear pattern on the left disk brake with
NEW rotor and pads and OLD caliper.

the NEW caliper fixed the rotor wear pattern, but the squealing
persists.

as for the sound, it can definately be heard with the windows down
inside the car. It's so annoying, loud, and high pitched (imagine a lot
crickets chirping simultaneously)

thanks for the input Carl.

 

[Vanguard]

Well, I've read up a lot on this subject and I'm getting mixed
answers:

I have a 1995 Subaru Legacy Wagon with 4 Wheel Drive and ABS. A
month
ago, the left disk brake brake started squealing. Its a really high
pitch squeal and only occurs when my foot is off the brake and
occurs
regardless of speed (Ive had it squeal anywhere from low speed to
highway speed driving). When I apply the brake, the sound goes away.
Likewise, when i turn the wheel left or right, the squeal gets
softer
or louder. Also, the squeal occurs randomly (drive to costco no
squealing but on the way back squealed badly). The squeal also
increases as the speed increases; say from 0-20 mph
squeak-squeak-squeak and at 40mph just sounds like one constant
loud,
high pitched squeal.

Here's the maintenance Ive done:
-Brand new master cylinder, new brake rotor, new brake pads, and a
new
brake caliper (all remanufactured)
-Applied disk brake anti-rattle but brakes still squealed, took
wheel
off to inspect and noticed that the anti-rattle compound had gotten
onto the anti-rattle spring (anti-rattle is really sticky stuff), so
I
completely cleaned off the pad and anti-rattle springs w/ denatured
alcohol and applied high-temp silicon brake lubricant on anti-rattle
spring (the part where the pad moves in and out) , but the squeal
actually got worse.

Here are a few things I've heard that solve this problem, but need
verification, please:
-Bad or failing hub bearing (I read that this makes more of a
grinding
noise, not squealing)
-Dust cover/plate on back of rotor (Ive checked for contact, but I
dont
see any)


As you can see, ive spent a lot of unnecessary time and money on
this
project, and at this point have run out of ideas. ANY help or
comments
would help TREMENDOUSLY. Thanks.

Could be the caliber piston isn't getting pushed all the way back.
That is, you release the brake pedal but the piston doesn't move all
the way back so the pads are still slightly riding on the rotor.
Could be rust on the piston, the seal on it that's gotten stiff with
age, or rust on the sliding pin so the caliber doesn't slide on that
side so the pads are at a slight angle and might be riding the rotor
(I've got that now and will have to see if I can clean it or have to
replace with a rebuilt caliber). My mom's Subie had the squeal when
the pedal was released which the shop didn't find the first time until
I got the guy to ride in the car so I show exactly under what
condition the squeal occurred in a big empty parking lot. They then
found a pebble stuck in the pad.

 

[Blair Baucom]

Also delamination of the brake hose can cause the piston not to return.

Blair

 

[Carl 1 Lucky Texan]

Carl 1 Lucky Texan wrote:




Yes, it does change with sweeping turns. Im not sure it the hub temp
issue, but i noticed an uneven wear pattern on the left disk brake with
NEW rotor and pads and OLD caliper.

the NEW caliper fixed the rotor wear pattern, but the squealing
persists.

as for the sound, it can definately be heard with the windows down
inside the car. It's so annoying, loud, and high pitched (imagine a lot
crickets chirping simultaneously)

thanks for the input Carl.

Although the sound is odd for a bearing, one characteristic of wheel
bearing failure is the change in sound in turns. If the sound is worse
on right turns, the left side bearing will be more heavily loaded from
body roll and will sound worse/louder. Obviously left turns more
severely load the right side.
Sticking caliper on the pins OR sticking piston might show very unequal
wear between inner and outer pad (inner heavily worn) as well as higher
wheel temp after extended driving.
I have also experienced a loud squeal in the past from a pebble stuck
behind the backing plate on a Datsun.

Carl

 

[webstericehockey]

Vanguard- Thanks for the advice, but I stated above that I replaced the
old caliper with a remanufactured caliper and the squealing persists.
Likewise, there is anti-rattle compound (really sticky stuff) on the
back of the pad so that the pad is literally "attached" to the new
caliper piston.

Blair- Delaminated brake hose? Can you explain?

Carl- When I assesed this problem for the first time, I went in there
to replace a Constant Velocity Joint. I did not notice any debris on
the dust pan, but afterwards, the dustpan was contacting the rotor just
a little bit and was blatantly obvious, so I bent the dustpan back so
there was no more contact. and yet the squealing is still there. Thanks
again Carl.

Obviously, the high pitched squeal is caused by the brake pad touching
ever so slightly on the rotor, meaning that something is not releasing
properly. This does not make sense, however, because the whole assembly
is floating (rotors, brakes). Yet, I cant fathom why a bad wheel
bearing would make a extremely high pitched noise.

 

[Blair Baucom]

Over in the Ford truck group it was discussed that sometimes the brake lines
to a single wheel would delaminate inside and would act as a check valve
allowing brake fluid to flow out to the caliper and when pressure was
released the fluid would maintain pressure not allowing the caliper to
release causing the brake to squeak.

You can search alt.trucks.ford

Not a common occurrence, but it looks like you have exhausted all of the
more common ones.

Blair

 

[Carl 1 Lucky Texan]

Over in the Ford truck group it was discussed that sometimes the brake lines
to a single wheel would delaminate inside and would act as a check valve
allowing brake fluid to flow out to the caliper and when pressure was
released the fluid would maintain pressure not allowing the caliper to
release causing the brake to squeak.

You can search alt.trucks.ford

Not a common occurrence, but it looks like you have exhausted all of the
more common ones.

Blair

You are correct and, I've been told, hydraulic in general can have
'flappers' inside that cause a check valve-type behvavior. Worth
considering but I'd still expect the offending brake system to wear
unevenly and produce heat.

I dunno


Carl

 

[webstericehockey]

Blair - That is very interesting. I never would have though of that.
I'll look into that some more. Thanks for the insight.

Carl- The uneven wear pattern was fixed by installing a new,
remanufactured caliper. Thanks, I'll definately look into the
hydraulics.


Now Ive heard another "myth": Could it possibly be caused by a failing
Anti-Lock Braking System?

Im confused by the fact that i have a new caliper, new rotors, and new
pads and the system is still squeaking. It's really throwing me off
that the squeaking goes away when i apply the brakes. I just dont know.

 

[Blair Baucom]

You are correct and, I've been told, hydraulic in general can have
'flappers' inside that cause a check valve-type behvavior. Worth
considering but I'd still expect the offending brake system to wear
unevenly and produce heat.

I dunno


Carl

Defiantly should produce heat. If it is bad enough, you should be able to
raise car off of the ground and have someone press the brake and release,
and should be able to feel a difference between the drag on one that is
working and the one that possibly does not release.

Blair

 

[Jim L]

Well, finally someone with the same problem as mine. I have been fighting
this for a year with my daughters 97 Legacy sedan. The symptoms are
identical with the exception of one thing. It doesn't always do it. I've
had the wheel, caliper and pads off and put anti-squeel goo on the pads. I
thought I got the wrong wheel so I took all four wheels apart and did the
same thing. I checked all the backing plates for clearance to no avail.
There is no abnormal wear on the rotors or pads. It seldom does it when I
am driving, but it drives my daughter nuts as she drives it everyday. If we
come up with any answers here, I would be most interested.

Regards and Good Luck

 

[webstericehockey]

Blair -Thanks, I'll have to try that method. When i first start the
car, i can hear the brake pad contacting, without my foot on the brake
(its like the sound one gets while driving with a very light rust on
the rotor). Not sure if that helps, though.

Jim- I know exactly what your daughter is going through. The sound is
so annoying and makes everyone turn heads to see where it is coming
from. However, I am experiencing your same problem. The breaks squeal
completely at random. I drove 10 miles to the store and had absolutely
no squeal on the way there, but on the way back, it really started to
squeal.

Things I've noticed:
- The squeal occurs very randomly, usually inbetween the brake pad's
respective "cold" and "hot" range; although the squeal came driving at
65 mph highway speed. Other times, the brakes start squealing at the
first stopsign in my neighborhood.
- The squeal is a very metal-on-metal high pitched squeal, indicating
that "whatever" is touching is contacting very slightly
- The squeal goes away when I apply brakes.
- The squeal changes tone and/or disappears while turning, even a very
slight turn.

- Somtimes I can make the squeaking noise by slowly releasing the brake
while coming off of a red light / stop sign. The squeak generally
increases with speed, turning into a constant whaling at high speeds,
say 40 mph.


Out of all the brake problems I've seen, this one takes the cake.

 

[webstericehockey]

Sorry for the double post, but i forgot to include one last thing:

This problem started when Advance Auto gave me the wrong size pads
for my Subaru. They were just 1-2 mm too big so I took 1 anti-rattle
spring out to accomodate. Things generally went downhill from there.
The brake pedal went to the floor, and there was a signifigant
reduction in braking power. So, I replaced the master cylinder, but
that didnt help.I replaced the oversized pads with the correct size
pads, and a few days later, the squeaking began.
Suspecting that the rotor had gotten bent due to the oversized
brake pads getting stuck in place (which i suspected was the reason
that the brake pedal was going to the floor), i replaced the old rotor
with a new rotor. Then i noticed an uneven wear pattern on the
squeaking rotor (Left Side Disk Brake) so I figured that the caliper
had gotten bent (somehow). Then I replaced the caliper, and the
abnormal wear pattern was fixed but the squealing persisted. Now here I
am.


The ONLY things I have not replaced in the entire braking system are
the brake hoses and the Caliper Support Bracket. I just dont see how
the forces involved in braking with oversized pads could possibly have
bent the caliper support bracket. Obviously something wierd/ambiguous
is wrong with my left disk brake, and im just hoping it doesnt have
anything to do with the steering knuckle or wheel bearing.

Thanks a lot for the advice.

 

[Jim L]

One thing I did emediately before the squealing started was replace the back
brake pads and had the rotors turned. The pads had been overheated and were
alittle burn't looking (both sides) The rotors had some slight surface
looking irregularities from the heat, but they turned out with just 10
thousanths off. I would normally not turn rotors, but this car only has 30K
on it. The previous owner lived on a hill and rode the brakes all the way
to the bottom. I think it is the right rear that is causing it, seems wierd
since turns seems to make it worse. Braking does make it stop, but it has
to be a reasonably good stop. Gradualy applying the brake make not stop it.

Regards, Jim

 

[rd]

I had this problem on my 99 OBW. One "cure" that works for a while is
to remove the pads on the offending wheel (mine was rear left) and
grind a 45 deg angle on the edges with a file. I ended up with about
1/8" lip all around the pad. Then I roughed up the disk rotor with a
disk sander with a 120 grit pad to lightly scratch the surface. I also
roughed up the pads slightly.
I'm not sure which step solved the problem, but it worked for quite a
while. Now the noise is starting to come back, so I suspect I need to
repeat the procedure.
I think what's happening is my wife drives the car lightly and
doesn't hit the brakes hard at any point so they end up glazing the
pads and rotor.
One thing to try before doing the above is to bring the car to a few
"hard" stops, one right after the other so the pads/rotors get hot and
the glaze gets removed.

 

[Carl 1 Lucky Texan]

I had this problem on my 99 OBW. One "cure" that works for a while is
to remove the pads on the offending wheel (mine was rear left) and
grind a 45 deg angle on the edges with a file. I ended up with about
1/8" lip all around the pad. Then I roughed up the disk rotor with a
disk sander with a 120 grit pad to lightly scratch the surface. I also
roughed up the pads slightly.
I'm not sure which step solved the problem, but it worked for quite a
while. Now the noise is starting to come back, so I suspect I need to
repeat the procedure.
I think what's happening is my wife drives the car lightly and
doesn't hit the brakes hard at any point so they end up glazing the
pads and rotor.
One thing to try before doing the above is to bring the car to a few
"hard" stops, one right after the other so the pads/rotors get hot and
the glaze gets removed.

As for the treatment of the brakes after re-assembling (or, indeed,
after replacing pads) check the tech paper at stoptech. good info there
I believe;
http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml


Carl

 

[k. ote]

-Dust cover/plate on back of rotor (Ive checked for contact, but I dont
see any)

Careful: if you've got it up on a lift, it's possible that you may not
notice any contact with the dust shield. Look for kinks, bends, or other
imperfections. If it appeared to be in contact once, it's possible it still
is.

The various weight affecting it in that other fellow's car is precisely the
symptom I had with my old '02 WRX. It was a dust shield in all cases that
was generating the noise.

 

[webstericehockey]

rd- Thanks for the insight, but im not sure i want to permanently grind
new pads and rotors.

Carl- thanks for the the website. I tried a series of high-speed stops
(a series being 2; the website reccomends 10 high speed stops) and it
fixed the problem for a few minutes, but came back again.

k. ote- I cant believe i did not think of that. I inspected it on a
scissor jack. Im going to go out and look to see if there is any
contact with the dust plate.


Thanks a lot for the help.

 

[bicknd]

rd- Thanks for the insight, but im not sure i want to permanently grind
new pads and rotors.

Carl- thanks for the the website. I tried a series of high-speed stops
(a series being 2; the website reccomends 10 high speed stops) and it
fixed the problem for a few minutes, but came back again.

k. ote- I cant believe i did not think of that. I inspected it on a
scissor jack. Im going to go out and look to see if there is any
contact with the dust plate.


Thanks a lot for the help.