floor leveling

I have an old Otis form the 1950's.I can not get the car to level on the floor in both directions one way the car is high other it is low by about 2". The top and bottom floors are fine.How do i fix it?
What is the proper prcedure to get the car to level on the floor? confused

If it's a single speed machine u will b relying on the break and your selector to stop the car. It's definitely not easy

Should I start by leveling the car going up or down first or doesn't matter?

With no load u want it to stop slightly above every stop. In both directions.

If this is as Jluff says, I'd check the brake, could need cleaning, adjusting, or could have crystalized any of these will let it slide.

Is it AC or DC? Sure sounds like an MG set that needs to be compounded.

1950s? Time for an upgrade
Would you feel safe travelling in a 67 year old car?

If it consistent in both directions your stop contact and your selector may have moved or it got moved. Ideally you'd want to do a compounding check on the genny. But considering its so old you may have to get by with adjusting the selector.

To Jim2007: when asking about Otis, find the data tag and post the "Type" on the data tag. If Possible wiring diagram number also.