Frint Brakes Squeal In Reverse when cold

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New Owner - 22 Jul 2007 23:42 GMT

Okay, here's an odd one for the experts out there.

I have a '96 LS400 w/62k miles on it. We just had it in to the Lexus
garage for its 60K mile checkup and mentioned to them that the front
breaks would sometimes squeal loudly when applying them wihile backing out
of the garage in the morning.

It only does it while backing
It only does it when the car is first operated after sitting overnight in
the garage. For that matter it can sit all day and we can back it out in
the 95-degree heat of the day and the dang front brakes will squeal very
loudly the first couple of times they're applied... only while backing.

Once you drive the car around the block you can back up, apply the brakes
and nothing is heard. Not a sound.

The brakes "work" fine and the 60k mile checkup at the Lex dealer turned
up nothing. They too said the brakes were fine.

What's going on here?

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Ray O - 23 Jul 2007 02:51 GMT

> Okay, here's an odd one for the experts out there.
>
[quoted text clipped - 16 lines]
>
> What's going on here?

When the vehicle sits for a long time, a thin layer of oxidation builds up
on the rotor, especially between the pad and the rotor. When the brakes are
applied the first few times after the oxidation has built up, the oxidation
is rubbed off while making a squealing, groaning, or scraping sound. Some
aftermarket pads or rotors are worse than others.

While the noise is annoying, by itself, there should not be any effect on
braking performance.

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Ray O
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New Owner - 25 Jul 2007 01:16 GMT

>When the vehicle sits for a long time, a thin layer of oxidation builds up
>on the rotor, especially between the pad and the rotor. When the brakes are
>applied the first few times after the oxidation has built up, the oxidation
>is rubbed off while making a squealing, groaning, or scraping sound. Some
>aftermarket pads or rotors are worse than others.

>While the noise is annoying, by itself, there should not be any effect on
>braking performance.

Thanks. What you say makes perfect sense other than the fact that the
brakes "all-around" are still the original brakes (pads, rotors, calipers,
etc) the car came with. Aside from periodic routine inspection, it has
never had a brake job. 62k miles and everything but tires and hood struts
are what the car came with when it rolled out of the showroom 11+ years
ago.

Oh, I take that back. At 30k the dealer replaced the battery, then at 62k
(6 weeks ago) the dealer replaced the spark plugs, both air filters,
serpentine belt and all fluids plus an oil change & lube & a complimentary
wash job. Not too sure how complimentary the wash was, as the dealer gets
a whopping $928 for 60k service (tho it did include pickup & delivery at
my office and a nice new loaner). >smile<

Short of replacing the brakes (which per the dealer do not need replacing)
is there anything we can do to solve this? The car sounds like an old
beater when I back it out of the garage every day.

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Ray O - 25 Jul 2007 03:12 GMT

>>When the vehicle sits for a long time, a thin layer of oxidation builds up
>>on the rotor, especially between the pad and the rotor. When the brakes
[quoted text clipped - 24 lines]
> is there anything we can do to solve this? The car sounds like an old
> beater when I back it out of the garage every day.

62K miles in 11 years! The low mileage probably makes the noise worse, on
top of which you probably do not use the brakes much since most brakes last
around 40K miles. The low mileage means that the car probably sits for a
long time, which means that more oxidation can build up. You may be able to
reduce the noise if you have softer aftermarket pads installed, although at
the expense of more brake dust on the wheels and shorter pad life. The low
mileage means that pad life is probably not a big concern for you, so that
may be a way to go.

The other thing that may or may not help is to scuff the rotors with a
Scotch-Brite pad and see if that slows down the formation of oxidation.

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Ray O
(correct punctuation to reply)

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New Owner - 29 Jul 2007 02:12 GMT

>62K miles in 11 years!

Yes and as you might imagine we've had a number of folks interested, tho
it's not for sale. Champaign Beige Metallic w/factory gold badging, coach
ed. but std suspension. The seat leather looks more like something with
30k, very minor wear, but we've religiously used Lexol on it through the
years, it's always garaged and only the dealer (Westside Lexus/Houston)
has ever done any service on it.

I was actually surprised at our recent 60k checkup that they didn't want
to put a timing belt on it, but I did ask and the dealer said it too was
fine.

I asked and was shown the rotors & pads when the tires were rotated and
the dealer is right there too, plenty of life left in them. Gosh these are
sure great cars!

> The low mileage probably makes the noise worse, on
>top of which you probably do not use the brakes much since most brakes last
[quoted text clipped - 4 lines]
>mileage means that pad life is probably not a big concern for you, so that
>may be a way to go.

Actually the car is a daily driver for my wife to use to & from grocery
shopping, Wally World, etc. though you're right, not many miles. A tank of
gas lasts her typically 6~8 weeks. I take it to work (50 miles round trip)
about once a month just to blow the cobs out, plus the fun of stomping
down on that big peppy V-8. We also run it up to Ft. Worth & back (~600 mi
R/T) once or twice a year to our son & daughter-in-law's home.

>The other thing that may or may not help is to scuff the rotors with a
>Scotch-Brite pad and see if that slows down the formation of oxidation.

Now there's something that I might try. Thnx for the tip!

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Ray O - 30 Jul 2007 05:32 GMT

>>62K miles in 11 years!
>
[quoted text clipped - 37 lines]
>
> Now there's something that I might try. Thnx for the tip!

You're welcome, and don't forget to scuff both sides of the rotors!

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