Re: '89 200TQ: urgent help with brakes needed.

[Pcarselle <pcarselle@worldnet.att.net>]

I6941tb@aol.com wrote:
> 
> Hello, virtual club!
> 
> In the light of a coming winter trip to Canada I fidally decided to adress an
> old problem with rear brakes:
> 
> I have a feeling that my RR caliper(s) are binding after:
> a) a spirited drive with a few energetic stops or
> b) when I travel at normal speeds with aplying brake pressure rather gently,
> but only with 4 people in the car.
> The car would not roll if I release the brakes on a light grade. Also the
> first 20-30mm of pedal travel become virtually resistance-free and I hear a
> faint hissing sound as the pedal goes through those 30-40mm. All goes away
> after half an hour of standing still.
> 
> I suspect proportioning valve, since it biases brake pressure forward (around
> 80%-20%) on an empty car or splits it up evenly (around 50%-50%) on a loaded
> car.
> 
> How can one test a proportioning valve?
> 
> It might also very well be one or both calipers.
> 
> At the Glen this summer the car wore out LT RR pads at about twice the speed
> of the RT RR pads. Now, this sounds like a LT RR caliper is binding. However,
> yesterday the RT RR wheel was warmer and smelled like burning the friction
> material, but a LT RR wheel did not.  A mystery.
> I have replaced the seals in both RR calipers this summer. The piston in the
> LT RR caliper did travel in the bore with a slightly higher resistance, than
> did the RT RR piston. I have also installed SS braided, teflon lined brake
> hoses (from GPR), so no clogging of the old rubber hoses is expected.
> I bleed the brakes religiously and I always use a pressure bleeder. The fluid
> is Pentosin and I do not expect any air in the sys to be found.
> 
> So, before I bite the bullet and buy two new calipers, I would like to rule
> out the proportioning valve.
> 
> Have anyone been there?
> 
> Thx in advance.
> 
> Igor Kessel

Igor:
Can you use Pentosin as brake fluid ???
You probably mean Pentosin in the Booster system. Right ?
Pablo