🚀 go-pugleaf

I notice recently that my Honda PRELUDE '85 also
vibrates when brakes are applied at high speeds -
about 70 mph or above. I have 16K miles on the car
and have not (yet) check the brakes. What would be
the problem? I haven't not driven on highway recently
in order to determine other factors that might
cause this irritation, such as humidity/rainy days/etc.

Any other PRELUDE owners out there experience the same
problem?

Khiem H.
homxb!khiem

> I notice recently that my Honda PRELUDE '85 also
> vibrates when brakes are applied at high speeds -
> about 70 mph or above. I have 16K miles on the car
> and have not (yet) check the brakes. What would be
> the problem? I haven't not driven on highway recently
> in order to determine other factors that might
> cause this irritation, such as humidity/rainy days/etc.
> 
> Any other PRELUDE owners out there experience the same
> problem?
> 
> Khiem H.
> homxb!khiem

I have an 85 Civic Sedan (vented discs) and had vibration on
braking starting at 10,000 km.  At 19500 km I got them fixed
under warranty (only took an hour or so to machine the rotors).
The dealer gave me a really hard time, claiming the warping was
due to lack of maintenance (not true, in my opinion).      

Anyway, I am at a loss to determine a cause.  The dealer (other
than being sure I was the cause) was not able to offer any explanation.
The brakes were not overheated, seized, or anything else.
I suspect (hope?) that there was some stress in the original casting
that caused them to warp spontaneously.  I also hope that this
spontaneous warping has now ceased.  

If the warping has not ceased, and this is a common Honda defect,
I would like to hear from others so that I can prepare my case when
my brakes warp again in a couple of months.

Aside:  I also have a '76 Honda.  The calipers on this car regularly
seize due to rust.  This wears out the pads instantaneously and has,
on occasion scored the rotor quite badly.  But the rotor has never
warped, and I have never had it machined.

> > I notice recently that my Honda PRELUDE '85 also
> > vibrates when brakes are applied at high speeds -
> > about 70 mph or above. I have 16K miles on the car
> > and have not (yet) check the brakes. What would be
> > the problem? I haven't not driven on highway recently
> > in order to determine other factors that might
> > cause this irritation, such as humidity/rainy days/etc.
> > 
> > Any other PRELUDE owners out there experience the same
> > problem?
> > 
> > Khiem H.
> > homxb!khiem
> 
> I have an 85 Civic Sedan (vented discs) and had vibration on
> braking starting at 10,000 km.  At 19500 km I got them fixed
> under warranty (only took an hour or so to machine the rotors).
> The dealer gave me a really hard time, claiming the warping was
> due to lack of maintenance (not true, in my opinion).      
> 
> Anyway, I am at a loss to determine a cause.  The dealer (other
> than being sure I was the cause) was not able to offer any explanation.
> The brakes were not overheated, seized, or anything else.
> I suspect (hope?) that there was some stress in the original casting
> that caused them to warp spontaneously.  I also hope that this
> spontaneous warping has now ceased.  
> 
> If the warping has not ceased, and this is a common Honda defect,
> I would like to hear from others so that I can prepare my case when
> my brakes warp again in a couple of months.
> 
> Aside:  I also have a '76 Honda.  The calipers on this car regularly
> seize due to rust.  This wears out the pads instantaneously and has,
> on occasion scored the rotor quite badly.  But the rotor has never
> warped, and I have never had it machined.

	Currently I own a 1982 SR5 Toyota Corolla and have had the same
problem with the brakes. The car now has 75K on it, but the brake problem
started when it had around 10-12K. This problem is not restricted to only
small cars, as previous to the Corolla I had a 1980 Pontiac Lemans. At
around 10K on it the brakes did the same thing. I had the rotors turned
and it helped, but within another 5 or 10K I had them turned again since the
problem was back again. After asking around, I was told the steel that's
used in the rotors is on the borderline and can't take the transitions
in heat/cold related to brake use. Softer pads would not create as much
heat, would cause less warping, but would wear out quicker. Overall, rotor
warping is an annoying problem which usually returns. New rotors might be
another solution, but there's no guarantee they won't warp either. One
last thing, my wife's car(1978 Gran Prix), mother-in-law(1979 Lemans),
brther-in-law(1982 Olds Cutlass), and a friends(1983 Olds 88), all suffer
from the same problem.
(

I have experienced the vibrating steering wheel during stopping on my 80
Accord at around 40,000 miles and now on my 85 Accord at 20,000 miles.
The problem was easily repaired by a Honda dealer who was able to turn
down the discs ON THE CAR.  It was a long, hard search to find one who
could do it that way, since most dealers and all tire shops I asked want
to remove the discs.  Sorry to say the dealer that did it for me is
located in Fairmont, WV.  The cost including new pads for the front brakes
is $65.

Regarding warped rotors:

> 	This problem is not restricted to only
> small cars, as previous to the Corolla I had a 1980 Pontiac Lemans. At
> around 10K on it the brakes did the same thing. I had the rotors turned
> and it helped, but within another 5 or 10K I had them turned again since the
> problem was back again. After asking around, I was told the steel that's
> used in the rotors is on the borderline and can't take the transitions
> in heat/cold related to brake use. Softer pads would not create as much
				     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> heat, would cause less warping, but would wear out quicker. 
  ^^^^

Wait a minute now.  The heat produced is exactly determined by the loss
in kinetic energy.  Energy_realeased_as_heat = .5 m (v1**2-v2**2), where
m is the mass of the car, v1 and v2 are initial and final velocities.

Now there might be some differences between pads in the distribution 
of heat between the pad and the rotor.  I don't know about that.

  -- David Jacobson     ...ihnp4!uw-beaver!fluke!jacobson

>I have an 85 Civic Sedan (vented discs) and had vibration on
>braking starting at 10,000 km.  At 19500 km I got them fixed
>under warranty (only took an hour or so to machine the rotors).

>Anyway, I am at a loss to determine a cause.  The dealer (other
>than being sure I was the cause) was not able to offer any explanation.
>The brakes were not overheated, seized, or anything else.
>I suspect (hope?) that there was some stress in the original casting
>that caused them to warp spontaneously.  I also hope that this
>spontaneous warping has now ceased.  

	Unfortunately, machined rotors are even more likely to warp than
	ones that have not been machined (since they are thinner). I had
	an '83 thunderbird turbocoupe (a real piece of trash I might add,
	but that's another story) that exhibited the pulsing at high(er)
	speed braking. I opted to live with it for fear that the
	machined rotors might result in even worse warpage.

Bob Schneider
ihnp4!hpfcla!hpfcll!rjs

In article <77800001@hpfcll.UUCP> rjs@hpfcla.UUCP writes:
>
>>I have an 85 Civic Sedan (vented discs) and had vibration on
>>braking starting at 10,000 km.  At 19500 km I got them fixed
>>under warranty (only took an hour or so to machine the rotors).
>
>	Unfortunately, machined rotors are even more likely to warp than
>	ones that have not been machined (since they are thinner). I had
>	an '83 thunderbird turbocoupe (a real piece of trash I might add,
>	but that's another story) that exhibited the pulsing at high(er)
>	speed braking. I opted to live with it for fear that the
>	machined rotors might result in even worse warpage.
>
>Bob Schneider
>ihnp4!hpfcla!hpfcll!rjs

I had the rotors machined on my '74 Toyota Corolla for what
was probably about the third time, and they warped again in about a
month. I opted to live with it until about seven months later when the
vibration had caused enough pad wear that one of the pads slid out of
the caliper... on a hill... with some jerk sideways across the lane in
front of me... Thank God that the emergency brake cable didn't snap.

My advice: make sure that you're brakes work!!! I check the pads about
every six months now, and the brake fluid every one or two. I also
wouldn't worry about the one machining. I'd even have it done twice if
it became necessary. You can check the manual for the minimum
acceptable thikness. Once it gets near this buy new ones! I would
never again drive a car with brakes that weren't perfect. You don't
almost die very many times!

BTW, my mother has an '81 Tercel that had the same problem. She had
the rotors machined at 20,000km (also under warranty) and has had no 
problems since.

Trevor J. Smedley                    University of Waterloo

{decvax,allegra,ihnp4,clyde,utzoo}!watmum!tjsmedley

> 
> >I have an 85 Civic Sedan (vented discs) and had vibration on
> >braking starting at 10,000 km.  At 19500 km I got them fixed
> >under warranty (only took an hour or so to machine the rotors).
> 
> >Anyway, I am at a loss to determine a cause.  The dealer (other
> >than being sure I was the cause) was not able to offer any explanation.
> >The brakes were not overheated, seized, or anything else.
> >I suspect (hope?) that there was some stress in the original casting
> >that caused them to warp spontaneously.  I also hope that this
> >spontaneous warping has now ceased.  
> 
> 	Unfortunately, machined rotors are even more likely to warp than
> 	ones that have not been machined (since they are thinner). I had
> 	an '83 thunderbird turbocoupe (a real piece of trash I might add,
> 	but that's another story) that exhibited the pulsing at high(er)
> 	speed braking. I opted to live with it for fear that the
> 	machined rotors might result in even worse warpage.
> 
> Bob Schneider
> ihnp4!hpfcla!hpfcll!rjs

*** REPLACE THIS LINE WITH YOUR MESSAGE ***

Bob:

A friend of mine had the same problem with his '80 Honda Accord.
He had went thru the channels and got no help, we think it is
a design or material problem but not sure. Let me give you a suggestion,
I have a '82 Celica and the black out coating on the windshield
molding peeled off at 20K miles. Since is out of warranty, I had to call the
factory rep out in cal. to come to the dealership and take a look at
the problem. I manage to convince him that it was a material problem,
and he fixed it free of charge. Well, I went one step further and
made him guaranteed the fix and responsible for all my future problems
relating to that item. Well the bottom line is that "Get in touch
with the factory, they are usually a lot more coorperative than the
dealers"