Bathroom · DIY guide
How to replace a toilet seat
Replacing a toilet seat is the cheapest visible improvement in a bathroom and needs no plumbing knowledge at all. The only part that ever causes trouble is the old fixings.
Legal to DIY in Victoria
What you need
- Replacement seat — measure first (see step 1)
- Adjustable spanner
- Flat screwdriver
- Penetrating oil or a hacksaw blade for seized bolts
- Gloves and a cloth
Step by step
Measure before you buy
Three measurements: the distance between the two bolt hole centres, the width at the widest point, and the length from the bolt line to the front tip. Most Australian pans take a standard fit but D-shape and compact pans do not. Photograph the pan brand stamped inside the bowl if there is one.
Get the old fixings off
Reach underneath and hold the nut while turning the top of the bolt. Plastic fittings often just snap off. Seized metal ones respond to penetrating oil and twenty minutes of patience — or, as a last resort, cutting the bolt with a hacksaw blade wrapped in tape to protect the ceramic.
Clean the mounting area
With the seat off you have access you will never have again. Clean the hinge recesses properly before the new seat covers them.
Fit the new seat loosely
Drop the bolts through, fit the nuts finger tight, then sit the seat down and check it is centred and square to the bowl before you tighten anything.
Tighten evenly
Nip both sides up alternately, firm but not hard. Ceramic cracks and it is not repairable. Most seats need a re-tighten after a week or two once the washers have bedded in.
Common mistakes
- Buying before measuring
- Overtightening and cracking the pan
- Not checking the seat is square before final tightening
- Forcing seized bolts and chipping the ceramic
When to stop and call someone
If the pan itself is loose on the floor, rocks, or weeps at the base, that is not a seat problem. A loose pan usually means failed sealing at the outlet and needs a licensed plumber before it damages the floor.