Shagwell,

I have read an interesting post you were involved with years ago about increasing the brake pressure to rear disk brakes on F bodies. I believe that you statd that you placed 3 washers in proportioning rear brake valve to shorten it up. Did this work?

I am in the process of gutting my stock valve and placing an adjustable one inline to my rears to try to get more holding power at the track. Just like many before me on jack stands my rear wheels will turn at a very low rpm with the brakes fully applied.

Thanks

 

Sorry, not shagwell but,
I had that issue on my 87, I searched and found that people actually remove that valve from the front of the perportioning valve that biases rear pressure. I did this and had to plug the hole on the cap that screws being the valve used to seal that hole, it worked great.

 

I answer to PM's as well, lol. Just not on here as often as I used-to be.


Yes, it works very well. IIRC, the front half of the valve(facing straight forward; out int he open) is the rear line. Three small "machinists" washers or thinner edge 3/8 hole electrical eyelet terminals clipp-off(thus just the washer piece) is a great starting place. I don't believe I've ever used more than 1/8 thickness total stack, but I usually start with three, test and change up or down as needed. - I've done this method to at least 5 different disc rear 3rdgens now; keeps you from having to re-plumb the system to install an aftermarket adjustable prop valve.

To properly test you need to do some typical running around town to have the brakes at operating temperature, then go some place you can safely do some "panic stops". You want the rears to lock up in the last 5-10ish feet of the braking distance. You do not want to simply set them to lock first as that can/will cause uncontrolable sliding during hard braking.