I recently pulled my pump due to a broken wire due to a broken wire, pressure had been operating fine. Once I reintalled into the casing I had to clear a lot of rusty water from tap screens, diverters toilet tank etc. Since I have reinstalled I have noticed that it will operate fine when called on for low volume usage. However when using the toilet, shower or washing machine (higher volume usage) the pressure drops to about 20 and holds taking about 5-10 minutes to recover to shut-off pressure of 50 after usage. Also while toilet or washer is filling pressure is low elsewhere.

Do you have a filter or softener on the system?