I first start driving. 'But of course' the door locks work but they are helped out with a electric pump on a 126 right?
The doors are _entirely_ run by an electric pump. The system is completely disconnected from the engine vacuum pump. You need to find out which system is leaking, if any, or whether or not your engine vacuum pump is OK. There's a spec. for how long it should take the pump to pump down an exhausted brake booster, but offhand I don't know what it is.
-- Jim
