That's the point I was trying to make about the design of the vacuum motor.
It has to seal tightly inside to have the torque to move the output shaft when it is loaded (linkage, arms, wipers etc.).
If it is leaking a little, it doesn't stand a chance against an electric motor for the torque.
The Electro-Vac (or pump and tank) is meant to compensate for periods of low vacuum.
It doesn't make the vacuum motor provide more torque at a given vacuum level.
Hope that makes sense.
I have motor specs for the Ongaro motor but unfortunately I couldn't find any specs on a Trico vacuum motor.
Without load:
Torque 15.6 Nm = 11.5 ft-lb
Current 1.2A
Speed Fast 59 (sweeps per minute)
Speed Slow 41
Working load:
Current 1.5A ~ 3.5A
Speed Fast 57
Speed Slow 41
Blocked spindle:
Torque 14.7 Nm = 10.8 ft-lb
Current 11.2A
All the automobile manufacturers went away from the vacuum wiper system for a reason.
If I converted to an electric motor I would not switch back unless there was need for an all original truck.
