I have a 2000 Integra GS, disc brakes on all four wheels. Recently
brakes have been grabbing and shuddering as I stop the
vehicle. The shuddering, or "rhythmic groaning slippage" as one of
my verbose friends calls it -- which can only slightly be felt
through brake pedal feedback, but is highly audible -- is directly
proportional to the rotors' speed and seems mostly independent of
brake pedal force. I think the noise comes predominantly from the
right / passenger side of the car, but I could be imagining that.
On any given day, the brakes do not exhibit this effect for my first
few miles on the road. It dependably starts occurring after about
ten traffic stops or so, then will generally continue on throughout
the day until I let the car have its beauty rest.
My first thought when this started happening was that my rotors
might be warped, so I had those replaced (they were thin from
previous resurfacing) along with the brake pads; this helped the
situation only slightly. Next I cleaned and relubricated the
caliper slider pins, and the symptoms went away completely for about
two weeks until the shuddering eventually came back. Then I
installed new slider pins (the old ones had several flat sides worn
into them, upon closer inspection) and relubricated all brake
contact points; likewise, the problem went away entirely for about a
week, then crept back, leading to a string of swear words of which I
am not proud...
So why am I telling you all this? I'm looking for some advice on
what to try next: I know the proportioning valve is a usual suspect
for grabby brakes, but wouldn't the shuddering's strict linear
relation to rotor speed, and the fact that cleaning and
relubricating the slider pins makes the problem go away reproducibly
(if only temporarily), instead point to a funky caliper bracket or
even a bad caliper? (Pretty please? My proportioning valve appears
to be built into my pricey ABS unit, dangit.) My optimistic next
move would by default be to replace the front calipers and caliper
brackets, which are only available together as a single unit; the
pistons are beginning to look a bit janky anyway. But I don't want
to waste the money and effort if you guys think the proportioning
valve, or something else entirely, is a much more likely culprit.
What do you think? Thanks!
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