Brake shudder

[Phil S]

Could someone who has suffered from warped brake rotors please tell me if
the problem is there every time you use the brakes???

I am suffering from an intermittent shudder in my Forester GT which only
happens occasionally (although getting more frequent).

thanking you... Phil S

 

[Djay]

On a '92 Ford Aerostar I felt the shudder only when I really had to "nail"
the brakes - then I could feel the pedal pulsing. With normal stops, I
didn't notice it. Replaced the rotors and the problem went away.

HTH,

DJay

 

[Phil S]

thanks for that.... looks like a visit to the repair man...

 

[Andrew Danielski]

Have that shudder on 97 Legacy when baraking hard at hwy speeds. The rotors
were resurfaced, it was OK for, ~40 - 50 KKm, now again, replaced rotors and
after 4 mo or so, doing it again. My friend mechanic telling me that some
cars need to have rotors reserfaced once, twice etc, before fibally working
OK. Any one has similar problems, wh?solution? AD

 

[Dan Chirica]

My car does the same thing, it is a '99 suby legacy outback. I plane in
changing the rotors myself. I was wondering is it a good brand I should
look for? Also, is it cheaper to change the disks myself or have them
resurfaced at a shop?

Thanks,
Dan

 

[FFF]

My car does the same thing, it is a '99 suby legacy outback. I plane in
changing the rotors myself. I was wondering is it a good brand I should
look for? Also, is it cheaper to change the disks myself or have them
resurfaced at a shop?

Thanks,

I put Brembo disks (plain non-drilled) on my 95 Legacy after the OEM front discs
were permanently warped. They still shudder when the disks get hot.

My guess: the wheel lugs weren't evenly torqued' - either that or that brand
isn't worth the money.

Florian

 

[Greg Reed]

I put Brembo disks (plain non-drilled) on my 95 Legacy after the OEM
front discs were permanently warped. They still shudder when the
disks get hot.

My guess: the wheel lugs weren't evenly torqued' - either that or
that brand isn't worth the money.

Florian

Brembos not worth the money? I'd be inclined toward the first guess.

- Greg Reed

--
1976 Cadillac Fleetwood 75 9-Pass sedan
(FS: http://www.dataspire.com/caddy)
1989 Audi 200 Turbo Quattro 5-Speed sedan
2000 Oldsmobile Intrigue
2001 Chevy Astro AWD (wife's)

 

[Carl 1 Lucky Texan]

Although the issue with lugnuts and, of course, manufacturing defects
causing pedal pulsing is possible, I've read that often 'warped rotors'
is a term used for improper/incomplete 'bedding in' of pads. One problem
occurs if, after a hard stop with new pads, the brake pedal is held
depressed allowing pad material to transfer to the newly turned (or
freshly installed new) rotor such that a 'footprint' of pad material and
/or bonding agent outgassed material is left in one spot. Thsi will
create pulsing and is evidently best removed by some type of deep
sanding or machining - again.
Try searching for the 'myth of warped rotors' or some such phrase -
interesting stuff.

Carl
1 Lucky Texan

 

[Verbs Under My Gel]

My car does the same thing, it is a '99 suby legacy outback. I plane in
changing the rotors myself. I was wondering is it a good brand I should
look for? Also, is it cheaper to change the disks myself or have them
resurfaced at a shop?

Thanks,
Dan

Dan,

The OEM rotors work well. Just be sure to never, ever over-torque the
lug nuts. This means using a torque wrench, a pnematic wrench with a
"torque stick" is no good for this task. The factory service manual
recommends tightening in 3-4 stages, in a cross pattern. By the way,
the torque is listed in your owner's manual.

Also, keep the caliper slides clean and lubricated. If one of the
pads is dragging on the rotor, it'll overheat and potentially warp.

 

[Edward Hayes]

My 2000 Forester with 62,000 miles are as smooth as ever. I of course
seasoned the brakes and tires by taking it easy on them for a few hundred
miles of progressively harder and harder stops without clamping and holding
the pads against hot rotors. I have never had a problem with any of my cars
and as said before my wheels are torqued to "manufactures specs" always.
eddie

 

[FFF]

My 2000 Forester with 62,000 miles are as smooth as ever. I of course
seasoned the brakes and tires by taking it easy on them for a few hundred
miles of progressively harder and harder stops without clamping and holding
the pads against hot rotors. I have never had a problem with any of my cars
and as said before my wheels are torqued to "manufactures specs" always.
eddie

```

Carl's explanation of the problem with soft (sacrificial) everyday pads leaving
prints on the hot rotors makes sense. However, wouldn't almost all vehicles with
automatic transmissions have this problem, since they do come to a complete stop
with the brakes engaged and usually remain that way for a few moments?

The brakes on my 95 legacy (replaced with Brembo rotors) start shuddering only
gradually after prolonged light braking. Therefore I tend towards the warping/
unevenly torqued wheel lugs theory in my case - it's no major problem anyway.

florian

 

[Carl 1 Lucky Texan]

I'm no expert, and am just parroting what I remeber reading, but issue
seems to be one with many variables; new rotor surface versus old,
new/different composition pad material, pad adhesive, 'spirited' driving
followed 'imediately' by 'clamping' of the brakes - lots of wiggle room
here, and evidently there can even be subsurface changes to the rotor
(localized 'tempering'?) that could make recurrence possible even if
proper bedding is performed. All this with or without improper torquing
of lugnuts. Brake systems are very much 'edge of the envelope'
engineering for most cars, designers need for them to work reliably yet
be inexpensive and lightweight to reduce unsprung weight. Most people
don't want to sqealing but they want short stopping distances. They want
then to work well in a short, sudden panic stop but have long life BUT
no fade under repeated/prolonged application.

ok-found the article-interesting even if you disagree.

http://tinyurl.com/2g9mn

Carl
1 Lucky Texan