Depending on your front suspension 70 pounds may not be enough.
I had a 96 motor home on a 95 P30 chassis. The vehicle owners manual described how to set the pressure in the airbags. In case you don't have the manual this is what mine said:
The owner’s manual gives the following ranges:
4,300 LB front suspensions = 10 psi to 50 psi
5,000 LB front suspensions = 40 psi to 50 psi
5,300 LB front suspensions = 50 psi to 80 psi
5,500 LB front suspensions = 60 psi to 100 psi
For the proper adjustment it says to inflate the air bags to the maximum pressure for your vehicle, load the motor home, park on a level surface and then reduce the air pressure as needed to level the motor home but don’t reduce it below the minimum.