SD Q1TF bad hammer in breaker?

[Badger]

40 year old square D QF1TF long span top fed.
I turned off 30 amp double pole to water heater and still had a closed circuit, then turned off the main above.
I then returned to reconnect service at main on service panel only to find that I now was experiencing voltage drop on outlets in home. EX: toaster on would drop voltage to appro 60-70 volts.
This is not over entire house but on some circuits.
Tested phase to phase at incoming = 220v
Leg to ground =110v on singles
30 amp double = 110v each but 0 ACROSS.
Neutral to ground = 0
Do I have a bad leg on main from bad contact on the hammers in breaker ? OR a neutral issue.
I also replaced all outlets in entire house.
This is a 1974 skyline mobile home with copper wire throughout
Thanks in advance.

 

[Megawatt]

40 year old square D QF1TF long span top fed.
I turned off 30 amp double pole to water heater and still had a closed circuit, then turned off the main above.
I then returned to reconnect service at main on service panel only to find that I now was experiencing voltage drop on outlets in home. EX: toaster on would drop voltage to appro 60-70 volts.
This is not over entire house but on some circuits.
Tested phase to phase at incoming = 220v
Leg to ground =110v on singles
30 amp double = 110v each but 0 ACROSS.
Neutral to ground = 0
Do I have a bad leg on main from bad contact on the hammers in breaker ? OR a neutral issue.
I also replaced all outlets in entire house.
This is a 1974 skyline mobile home with copper wire throughout
Thanks in advance.

You have a neutral issue if your reading if you are getting that low of voltage. One of the outlets that you changed has a bad connection with a loose neutral. Probably just on 1 circuit

 

[Badger]

You have a neutral issue if your reading if you are getting that low of voltage. One of the outlets that you changed has a bad connection with a loose neutral. Probably just on 1 circuit

This happened after I turned off 100amp main, not after I did the receptacles.Things were fine before.
The Breaker is over 40 years old and is discontinued. Sd Q1tf top feed. I have lost the neutral on one leg at the breaker is my best guess.

 

[Megawatt]

This happened after I turned off 100amp main, not after I did the receptacles.Things were fine before.
The Breaker is over 40 years old and is discontinued. Sd Q1tf top feed. I have lost the neutral on one leg at the breaker is my best guess.

Then I suggest that you upgrade your main panel to a safer 200 amp panel. Good luck with your project