Plumbing – Garbage disposal replacement: how much to replace

garbage-disposalplumbing

I'm replacing an Insinkerator Badger 1 garbage disposal with the same model. The original leaks. One leak is internal, and water comes out holes in the bottom cover only when it is actually operating, But there is also some dripping higher up on the outside of the body. It's in the vicinity of the outlet pipe connection, but I can't be sure if it's coming from that connection or higher up. The sink flange seems to be water tight.

The new unit was advertised as "quick change", which I assume means you can just lock it onto the old sink flange and mounting ring. However, the original unit was in place for about 12 years, so there's a good chance the original plumber's putty is brittle. I'm not sure if the torque and banging around of removing the old unit and locking on the new one will disturb things and create leaks at the sink.

There is also a dishwasher connection. There's a corrugated plastic tube that goes into a rubber sleeve that is secured with a compression clamp to a barbed inlet tube on the disposal. That rubber sleeve is also 12 yrs old. I have no idea of the extent that those deform over time or become brittle (how reliably they can be reused).

The instructions don't discuss quick replacement, they just show how to install everything from scratch. It isn't clear whether that's meant to imply that everything should be replaced, or that common sense would tell someone to just skip ahead to the part where you lock on the new unit. It's also silent about reusing the dishwasher connection, it just show how to connect one.

So my question is for people who have replaced a lot of garbage disposals.

  • Is the sink flange designed to last "forever" once installed, and normal practice is to just leave it in place and attach to it, or is that unreliable, and best practice is to always just replace it?
  • Is normal practice to just reattach the old dishwasher connection, or is that unreliable and the sleeve should be replaced?

Best Answer

  1. I wouldn't rely on the old flange. While the flange itself might be fine, there's plumber's putty between it and the sink. That stuff doesn't last forever, and if you knock it loose replacing the disposal, you'll wind up pulling it off and adding it anyways. The good thing is it's not crazy hard to get off or put the new one on.
  2. The dishwasher compression fitting depends a great deal on what they used and what condition it's in. I was able to keep the same one (rubber) when I replaced mine a few years back, but be sure to inspect it for cracks and leaks. It can't hurt to replace it either.