View Full Version : Leaking Prop Valve and Tuning?

09-13-2004, 07:26 PM
Alrighty, well this is my first new thread on the new and improved site! I have two questions! One is concerning my prop valve. I put all of the lines together and all of the fittings are flared except for the two fittings that go into the prop valve! Beacuse the two threaded holes in the prop valve did not have a regular brake flare I put on some teflon paste to seal the threads and when the motor warms up (prop valve is on the fender by the master cylinder) the heat causes the paste to liquify and run out causing the prop valve to leak around this area, but the odd thing is it only leaks on the "IN" side of the valve! Could it be that I have to much pressure on the "IN" side and this is also causing leaks? And my next question is... What is the correct way to "dial in" a prop valve? Go out and do hard stops from 60 and keep cranking the valve in til it locks up the rear tires then back it off some?? Just want to be sure I am using the full potential of the rear discs. The fronts are stock disc setup while the rears are Wilwood 4 piston! Thanks guys!

09-15-2004, 02:36 AM
Come on guys I know you are out there!

09-15-2004, 03:29 AM
Just to verify: The ports on the prop valve are not for flared lines? What brand is it?

09-15-2004, 05:29 AM
Correct, the ports on the prop valve are not flared. It is a Classic Tube prop valve! And what are your reccomendations for adjusting it. Right now I have it set at 4 full turns out, out of a possible 8 full turns! Thanks!

09-15-2004, 05:43 AM
If it's leaking, I don't think I'd be too worried about adjusting yet. The setting will be unique to your car, but I'd hate to even start the dialing in process with it leaking... if fluid is getting out, air may be getting in and you'd get pretty inconsistent results.

I do seem to remember reading that teflon tape/paste should never be used with brake lines.

I'd probably give Classic Tube a call and see what they recommend.. it may be that it should be flared and they just had a bad batch go out -
I'm having difficulty coming up with a reason why they wouldn't have it set up for flared lines.

Rick Dorion
09-17-2004, 08:20 AM
The prop valve has NPT threads and takes the correct adapter to mate the brake line to. The brake line fitting doesn't go directly into the PV. Any good auto parts store should be able to hook you up. Once your leaks are history, you need to go out to a safe area of road and do some maximum effort braking, while dialing in more rear brake bias, until you just start to lock the rears; then back off to where the lockup stops.

09-18-2004, 07:36 AM
Thanks for the input guys! Yes, Classic Tube sent the correct NPT fitting to install the brake lines, but I used Teflon paste to seal the threads going into the PV and when the engine warmed up so did the paste and it ran out causing the threads to have absolutely no sealer, that is where the leak came from! Yesterday I drained the master cylinder and used Teflon tape instead of the paste to seal the threads. No leaks!!!! I let the engine warm up as warm as it will get (180 :fingersx: ) and still seems fine! So I geuss the catch is to not use the paste anywhere there is heat involved! I shoulda known! Thanks Rick for the input on the adjustment! Now I have the leaks cured (once again :fingersx: ) now I can tune it in!