Vacuum pump and brakes.

All cars use a servo braking system and therefore this system has to be kept the same in a vehicle converted to electric. As the weight increases a little more if the car is charged with batteries, the brakes should maintain the same braking power or more. Consider that the "engine braking" used downhill in an electric vehicle does not work, or at least not as much as with a petrol engine if the electric motor is designed to use regenerative braking.
If the car would be much heavier after the conversion, then even larger brake discs would have to be fitted.
The difference in the braking system in an electric car is not the braking system itself, but the system with which the vacuum is applied to the brake booster, which in an electric car has to be done with a vacuum pump.

A vacuum pump is the same as an air compressor, but with the valves changed to draw in air instead of expelling it. In a normal car the vacuum pressure level is 16" to 18" Hg (inches of mercury), which is about 54,000 Pa (pascals) or N/m2 (Newton/m2), so this vacuum pressure level is what the vacuum pump you install should have.
Electric vacuum pumps are found on some diesel cars such as Volvo and vans whose diesel engines do not provide as high a level of pressure. These pumps operate at 12V and usually draw a current of about 6 or 7 amps. Vacuum pumps used for central locking systems on cars should never be used, as they have a very low vacuum level, which is insufficient for a braking system.

Sometimes long braking can use up the pressure induced in the circuit, so that a few seconds will have elapsed before the pump will reintroduce that pressure. To avoid this situation, a vacuum reservoir (what a paradox, a reservoir that stores vacuum...haha) can be installed between the brake booster and the pump, to maintain extra vacuum pressure. The larger the reservoir, the greater the braking capacity, i.e. you can brake for more seconds without the pump generating more vacuum again.

For this tank system to work, there must be a sensor that maintains the vacuum pressure level always above a given value, in our case 15" Hg. These sensors have an associated valve that opens and closes the circuit so that the pump continues to maintain that pressure level.

The handbrake or parking brake must however continue to function regardless of the conversion in the braking system as well as the regenerative brake if the engine to be installed supports it.

The vacuum pump and components pictured, are very popular US conversions (SSBC pump), and Hella brand pumps. I ordered one from the USA for 200$ plus 60$ shipping and handling. The surprise is that when I received it, after paying 90€ of customs taxes, I discovered that it was Made in Spain, manufactured entirely in Navarra and re-imported to Spain.