I converted my 1988 Vanden Plas from the hydraulic brake booster system to a vacuum system. I am happy to not have any more green mineral oil leaking, and to have really good braking that is similar to my 2021 vehicle. The only issue I have is that, on occasion (2% of the time), the brake lights remain on. When I pull the pedal slightly toward me they turn off. I can adjust the brake light switch at the pedal box but I am thinking, since the issue rarely occurs, that may not be the remedy. Could the cause be a result of the booster not being broken in and over time the issue will work itself out? Should I adjust the switch at the pedal box by moving it forward or backward? Should I just give a strong tug on the pedal from inside the car pulling it toward me?

 

Try setting the pedal switch to the right of the pedal in the engine compartment. Loosen the 3 bolts and move the set plate / switch.
Otherwise you have to adjust the Mastervac.

Marc

 

Move the brake switch to the right. Do you mean forward, away from the firewall?

 

In the engine compartment you have on right side of pedal switch fix with 3 bolts.