Re[2]: Brake calipers

[treilley_at_BANKMARK@conseco.com (treilley)]

     I have replaced pads once and cut 2 different sets of rotors three 
     times.  The shimmy is cured by cutting the rotors but returns a few 
     months later.
     
     Tim 90CQ, 77Spitfire


______________________________ Reply Separator _________________________________
Subject: Re: Brake calipers
Author:  GADBOISMT@aol.com at Internet
Date:    4/8/96 12:08 AM


In a message dated 96-04-07 12:12:56 EDT, you write: 
>
>On Sat, 6 Apr 1996, treilley wrote: 
>
>>      Do single piston type calipers cause more warpage than dual(1 piston 
>>      on each side)?  A mechanic told me they did because they exert more 
>>      force on one side of the rotor than the other.  Sounds to me like 
this
>
>>      guy has been talking to too many "old wives". 
>
>Warpage isnt a function of how much force is applied to the rotor, its a 
>function of heat. If you can get the heat away, by either rotor design or 
>wheel design, cooling, ducting etc then you wont have problems.  If you 
>exert more force on the rotor, it does equate to more heat which needs to 
>be removed however, but they do not warp BECAUSE of the twin pot clamps.. 
>
>Bob
>
     
Don't know if I agree with this and I'll have to toss in my $.02.  I had a 
1986 5000T. The front brakes were the dual-piston type.  The vibration during 
braking was absolutely horrible.  In the course of trying to cure the problem 
I managed to: cut the rotors, replace the rotors (twice), replace the brake 
pads, replace some suspension busings, etc.  Almost all the work was 
performed by the dealer - some under warranty and all paid by someone else 
since it was a company car. Each "fix" would make the car well for two weeks 
but within 500 miles the vibration was back.   Eventually I dumped the car, 
never thoroughly solving the problem.  I now have a 1989 200TQW which has the 
single piston type.  These things are beautiful.  Never a shimmy - stops 
great.  Pads cost a small fortune (>$100), last only 18 months but work 
great.
     
So the question is do you really have warpage or do you just have a shimmy 
and THINK that it is caused by warpage?
     
Mark