Brake Gurus I need help!!!!!!

[Hydratech®]

I'm willing to bet that your MC pistons are preloaded, not allowing a full state of release against the snap ring in the back side of the Wilwood MC. When this happens, you can (believe it or not) suck fluid out of the rear brake line (as the cup seals in the MC are designed to balloon and hold pressure, but have little to no effect against vacuum). This would be very simple to "nail", as all you would do to verify this is loosen the MC mounting bolts / nuts up some and then you should be greeted by capillary / gravity bleed actions (as a result of allowing the preloaded MC pistons into a full state of release). Our BRAKE BLEEDING 101 online tech applies to manual and power brake scenarios - read it over thoroughly:

http://hydratechbraking.com/braketech1.html



If my hunch is correct, you will have to adjust your MC mounting scenario to allow for definite full release of the MC pistons when the brakes are not applied. You can temporarily rig it by installing washers between the MC and its mounting to shim the MC further away. In some cases these means taking a carbide burr on an air motor and removing a few thousandths of material from the MC piston apply area (surmising you likely have the Wilwood spacer bullet installed into the deep MC pushrod hole in use with a short rod vacuum booster). BTW - FYI - we have observed that Wilwood has very recently started supplying an updated spacer bullet / plug design that addresses this issue (removing MC piston pushrod preload in vacuum booster installations).

Or? Start using compressed air testing of your brake lines to see what in the world is going on. If you can use a (preferably rubber tipped) blow gun to get compressed air through your lines, then brake fluid will also certainly flow through. I certainly hope that you haven't used any Teflon tape anywhere in your installation...