I recently rebuilt the brake servo unit on my 66 Series V Alpine while waiting for the machine shop to finish up the head. After reassembling everything and bleeding all the air out of the braking system I started the car up. The brakes locked on so hard I could not move the car. I disconnected the vacuum line and the brakes eased up enough I could get it in the garage before it started raining. I noted the following when I took the servo unit back out and started scrutinizing.
1) Still quite a bit of residual pressure in the brake system as witnessed by brake fluid coming out of the outlet port.
2) The Tee lever in the air chest was still allowing ambient air to the head side of the piston. This indicates to me that the control piston is not retracting.
3) The output piston seals provided in the rebuild kit from VB are not the same as those shown in the workshop manual . The seals in the kit are your basic U cup seal. Those shown on the control piston in the workshop manual are not. Removing and inserting the control piston takes a fair amount of effort. It would seem to me that the piston should move fairly freely back and forth and pull back to the position that the spring draws it too. (i.e. vacuum to the head side of the cannister piston).
4) The cannister piston moved freely and was properly centralised with the output piston.
I am sure I am not the first guy to rebuild one of these units and could use some input! Do the seals in the rebuild kits differ depending on who you buy them from or is it basically one supplier. Any help would be appreciated!
Bob Flak Sandy, Or.