By Don Nester
Chapman Report – April 1979

After going through a total engine rebuild and a body repair experience that I wouldn’t wish on my worst enemy, I thought that I would have exhausted my supply of experiences to write about. Not so with a Lotus! A Lotus will always provide experiences to share with your fellow Lotus owners.

During the repair of the accident damage to my car, I had to remove a brake line which required bleeding the brakes. Not reading the shop manual, I proceeded to bleed the brakes as with a normal car. This caused the brake fail mechanism to be activated. After reading the manual, I followed the procedure to correct the situation… Then after a lot of spent brake fluid, four letter words and several rereadings of the shop manual, I gave up and pulled the wires off the brake failure switch. (After all, the car was still driveable). At this point I was resigned to the fact that I would have to disassemble the switch and manually recenter the valve which would turn off the brake warning switch. After considering the problem for a significant period of time and pondering several possible alternatives, I developed the following corrective procedure:

After bleeding the brakes using standard techniques (which I recommend) the brake failure warning light will be lit. This is a result of a pressure differential between the front and rear brakes which causes the brake failure valve to be forced to the failure side (front or rear brakes), which causes the brake failure switch to be activated. The recentering of this valve (ie. Turning off the brake failure switch) may be accomplished through the following procedure:

1. Start engine.
2. Remove vacuum hose from brake servo that controls the brake pair which was not initially bled. (Top servo controls rear and bottom servo controls front… ie. If you bleed the rear brakes first, then disconnect the servo for the front brakes).
3. Stop the vacuum leak (metal tube) by placing suitable stopper over the metal tube. I used one finger of my mate (mate fully attached) which worked perfectly.
4. Depress brake pedal firmly and quickly. This should center the valve and the brake fail light will go off. If the light blinks, guess what… you forced the valve to the other side. So, switch servos and try again (only not quite so firmly on the brake pedal).
5. If the light does not go off nor does it blink, depress the brake pedal more firmly and quickly. If repeated tries fail, assume you were confused and switch servos and try again.
6. If this also fails, take apart the brake fail switch; center valve; and reassemble and re-bleed front and rear brakes as described in the work shop manual.