American Standard Champion 4 Toilet Tank Leaking

Last week one of my units had a hairline crack in the toilet tank flooding the half bath and the adjoining kitchen.
American standard champion 4 toilet tank leaking. Shut off the water to the toilet. I bought a pound of 10 gauge plain solder not acid or rosin core and wound it into a coil using a soup can. Went out to buy universal bolt repair kit. They should not be really tight as it is recommended to just hand tight them to avoid breaking the porcelain tank or bowl.
Https amzn to 2l4hjqk american standard 3174 105 0070a champion universal. Go back and forth until the tank is secure. Water leaks between the tank and the bowl. Remove toilet tank old bolts.
Next day i noticed that the toilet bolt closest to the water supply line was leaking wet. Using the same wrench or channel lock pliers remove the nuts that hold the toilet tank in place. Bought an american standard champion 4 toilet last weekend and installed easily. Using a wrench tighten the nuts on each side one quarter turn at a time.
Take note that the american standard has a repair kit with a couple of parts namely the rubber seal and the o ring seal. After about two years of usage this will cause some leaks or running water problem. A couple of years ago i posted a question regarding the best toilets for rental properties. This is symptomatic of a leak in the tank to bowl seal or around the tank to bowl mounting bolts.
Replaced the weird rubber nipples that come with the as toilet with the new regular bolt assembly. How can i repair this. The authentic american standard replacement gaskets are now available on amazon. When i flush the toilet i noticed that water seems to leak on the floor from between the tank and the bowl.
Follow the following steps for a quick and sure repair. Remove the tank cover and place a level across the top of the tank. Do not turn the bolts. You need not have to replace the whole toilet tank valve assembly for this matter.
The 4 flapper valve chronically leaks but then it only has about 2 inches of water to hold it in place. If the bolts start spinning you will need a screwdriver to hold them inside the tank.