We have an early Vax, model 121. SWMBO was complaining that the suck wasn't as good as it used to be, despite her cleaning all the filters, and would I have a look in the motor housing to see if there was anything wrong.
Removal of the underside of the motor housing (four bolts) reveals a floating circular plate with both rectangular and circular holes in it, four springs, and another plate with the blue filter pad, that abuts the motor itself. Needless to say, muggins committed the cardinal error of disassembly and forgot to note the order that they came apart in!
The uncertainty lies with the floating plate and the springs. Can anyone tell me whether the springs should be on the motor side of the floating plate or on the filter side, and whether said floating plate should have the side with the countersinks on the round holes facing the motor or facing the filter unit.