Rocking toilets — If this terminology rings a bell in your head, it probably takes you back to an unpleasant experience, or rather a period of your life…… about your bathroom experience. And in case you can relate to this even today, now is when you stop worrying about it. Because, in most cases, this trouble is well within the scope of an average person and does not necessarily require the expertise of a plumber.
The core issue in such scenarios, most often, is at what’s known as a toilet flange, or a closet flange. This mechanical part is responsible for connecting the drain of your toilet to the drainage system. It also provides strength and stability to your toilet, while mounting it to the floor.
It is a fairly straightforward procedure to replace your toilet flange with a new one, provided that you have the basic tools usually found in a household, and the material required to install a new toilet flange. But before we rush to the tools and the materials required, let us go over some indicators to help you determine whether you need to install a new toilet flange.
Indicators:
Leaky base of the toilet
If you notice a leak at your toilet base, your first thought should go towards an issue with the closet flange. Following are the two possibilities of things that could have gone wrong.

Broken or a Cracked Toilet Flange
If your toilet has been working fine and suddenly started leaking, it’s most probably a matter of a broken or a cracked flange that will need to be replaced. In some cases though, where the damage is minimal, a ‘toilet flange repair ring’ may be capable of doing the job, but remember, only for the time being.

Wrong size of Toilet Flange
In case you have just installed a new flange, yet your toilet has begun leaking around the base, chances are, that you installed a flange which did fit properly with the size of your toilet. In this case, you will need to replace it with the correct size.
Rocking Toilet
Just as the first word of this article suggested, a loose toilet that rocks back and forth is not only annoying but worrisome too. It is primarily the job of the toilet flange to hold the toilet in place with the help of bolts while connecting it with the drainage pipes. The problem could either be with the flange that it broke, or it may be with these bolts; they may have broken, or become loose.
This problem also arises in another common scenario when you have recently redone your bathroom flooring. It is very important that the flange is at an appropriate level with the flooring around it, in a manner that the drain pipe fits correctly with the flange while the overall toilet is evenly placed on the floor. If the flange, after the refurbishment, happens to be too low, a flange extender can do the job for you.

The toilet backs up
If you notice that the stuff you sent away by flushing the toilet, making its comeback to your toilet bowl, know that there is some blockage along the path. This could occur in the flange as well. At this stage, you do not have to replace the flange. Instead, by using the proper tools, you should be able to unclog your toilet flange, thus relieving it of the gunk.
In case you struggle, do not hesitate to call in your local plumber.
Foul smell of the Sewage
Yet another indicator of a faulty toilet flange is the presence of unpleasant odors in your bathroom. This means that they are able to escape through the wax ring, installed to prevent it. In some cases, the flange overall could be absolutely fine but its wax ring breaks. It is possible to replace the ring alone, as well.
A heads up before proceeding
Before we proceed on to the How’s, remember that all of the above-mentioned indicators could also be hinting towards another, a perhaps more severe issue with your toilet or plumbing. Do what needs to be done and proceed with replacing the existing flange only once you’re certain about the problem.
Steps to install a new toilet flange
Remove the water
The first step will be to drain out all the water present in the toilet setup:
Begin by turning off the supply line to the tank and disconnecting the outflow pipe that goes to this tank. Then flush the toilet until the bowl is empty. It could take more than one flushes.
Go a step further and use a toilet plunger to push down any remaining water out of the base of the toilet.
Detach the setup
Now that the whole setup is free of any water and the supply is disconnected too, it is time to dismantle it.

Carefully detach the toilet tank from the bowl by first taking off the bolts connecting the two with the help of a socket wrench. Put the tank aside, preferably at a distance since it will not be required until the end of the procedure.
Now, remove the bolts mounting the toilet onto the bathroom floor; if these bolts have plastic caps, make sure to take them off first too.

With the help of a cutter, cut through the caulk applied at the base of the toilet, in order to provide it with a seal alongside the bathroom floor. This will be reapplied later when the previous flange is renewed.
Removing the toilet
The final step to remove the toilet is to break through the seal of the old wax ring. To achieve this, repeatedly but lightly rock the toilet bowl from side to side. As soon as the old wax ring is broken, you will be able to lift the toilet off the floor. Remember that on average, the toilets weigh at least about the same as an 8 year-old kid, so, depending on your strength, you may use a hand for this step.
Source: https://thriftdiving.com/how-to-remove-your-toilet-by-yourself/
Lay it on its side so you may get access to its lower part. Do it on a towel or another softer surface, for if you place it directly onto the bathroom floor, you may risk damaging it.
Be prepared though, at this point, you may start smelling lots of unpleasant and unwanted smells. If you are going to take long, you can block the passage with a piece of cloth AFTER removing the existing toilet flange.
Replacing the existing toilet flange
Once the old wax ring seal is broken, the part of it stuck on the bottom of your toilet may look messy, something as shown in the picture above. With the help of a putty knife, remove the old wax. Do the same for the part of wax on the flange end of the system. Be sure to wear your gloves so you don't get your hands dirty.
Now, remove the old flange lip from inside the existing toilet flange and discard it. Take out the flange bolts and the screws of the old flange and clean the area around the mouth of the drain pipe.
A quick timely tip
If you are not entirely sure about the dimensions and the size of your toilet flange, use this opportunity and take your old flange to your nearest store and let them give you one, of the same size. And meanwhile, your toilet is detached, do not forget to block the passage of the drain system with a piece of cloth (such as an old towel) or you will be coming back to a very unwelcoming environment powered by foul odors.
Discard your old flange. Now is the time to introduce the new toilet flange. Place it gently into the designated cavity, fix it onto the subfloor with the help of new screws, and then fix the mounting bolts into the new flange and tighten each with a plastic washer.
Fixing the new wax ring
Next, fix the new wax ring around the flange lip and insert the whole set into the drain, such that the wax ring erects out of the system (shown below).
Alternatively, you may also fix the wax ring on the drain of the toilet and let it fit onto the new flange (shown below), though the first method seems to be more practical.

Additional Things You Might Need
When you need to install a toilet flange, you obviously need all the importance parts to replace a toilet flange. This might include a tap plastic wall anchors, a putty knife, a flange kit (if you can find a good one at your local hardware store), pvc flange, rubber gasket, a metal hose, overflow pipe, plastic bag to keep any of the small parts from being lost, two bolts, and equipment to pre cut holes.
Reassembling the setup for your toilet flange installation
Lift your toilet bowl again and place it very carefully over the new flange so that the bolts of this new flange go into the holes of the bowl. You will now need to apply some pressure downwards (do it by gripping onto the bowl rim) so the wax ring sits correctly with the drain of the toilet and is sealed. Allow it to settle and do not rock or tilt the toilet anymore as it will damage the seal created by the ring.
Bring back the bolts that mount the toilet onto the floor and tighten their nuts. Be very careful not to over-tighten them as that may result in damaging your bowl. If your bolts had caps, place them back over the bolts (see below).

Before bringing back the toilet tank, at this point, you can pour water into the toilet bowl and observe if there are any leaks. If you have carefully followed the instructions and have chosen the correct size of the toilet flange, you should not have any toilet leaks.
Now, reattach your flush tank with the toilet using the bolts (tighten their nuts carefully). Connect the water outflow pipe to the tank again and turn on the water supply.
Let your tank fill, give it one final flush, and Viola!