HILO Stink Pipe Repair

I'm not sure why, but at some point, the flange on the stick pipe broke and caused it to fall down. This pipe essentially vents the blackwater tank outside the trailer. Because the upper section raises and lowers, the pipe must raise and lower as well. To accomplish this feat, HILO used a length of ABS pipe with a sliding drain pipe tailpiece inside to outer pipe. It's a clever design that is pretty simple to replacate, with the exception of no one making tail pieces long enough to work. The typical tailpiece would be used under the sink attached to a garbage disposal unit. This piece needs to be 4 feet long!

My fix was to use the original tailpiece pipe, cut the damaged flange end off and then solvent weld a new flange on.

HILO used a "Female Trap Adapter" to make the assembly, but each part is also available separately. The "Female Trap Adapter" consists of three parts:
  1. A "slip joint nut". This is the female threaded ring.
  2. A plastic sealing ring (aka sealing washer) - Flat part faces the slip joint nut
  3. A male thread adapter. This is at the ceiling
The slip joint nut and seal go over the unflared end of the slip joint pipe (aka slip joint tailpiece). The slip joint pipe is normall a molded one-piece pipe that has a flared rim at one end. Perhaps no one made one the length HILO needed, so instead, HILO used an ABS tailpiece pipe with a flare glued on the end to form the slip pipe. You have to look closely to see the glue. This is the section that falls down when the female slip joint nut is loosened. Without the solvent welded flange in place, the upper inner pipe would drop down all the way into the lower outer pipe.

Broken Blackwater Vent Flange - I cut this off with a fine-tooth wood saw.
Blackwater Vent Broken Flange

ABS Pipe Test Cap - I cut the center out of this with a Dremmel tool. It works well because this cap is supposed to fit the inside of the ABS pipe so it's similar in size to the tailpiece.
ABS Pipe Test Cap

Dremmel Cutters - Either bit wil work
Dremmel Cutting Tools

Finished Flange Repair
Finished Repait of Broken Flange

Tank Vent Top
1994 HILO Travel Trailer

   Last update: Dec 7th, 2019