I have incrementally been replacing the vacuum hoses on my car over the past year with Viton and have been using the Nylon barbed fittings from mcmaster.com (pg. 127 of the current catalogue) that people have recommended. I was never very happy with them - they are bulky and the barbed ends are either too tight or too lose in the hose for their nominal size.

So I looked around for a suitable high temperature replacement and found some very nice Kynar fittings from a company called Small Parts Inc. I ordered a number of 3/16"-1/4" reducing connectors (which was as close I could get to a 4mm to 6mm size) and some tees and other fittings to try out.

They are pictured here:



The adapters work very well with Viton to go from 3.5mm and 4mm ID hose to the 6mm ID size. The tees and other fittings also work very well. They are easy to install and grip tightly but they can be removed without drama. They are also less bulky than the Nylon fittings from McMaster.

After ordering them, I discovered that McMaster now also have Kynar fittings (pg. 132). I think they sell every fitting imaginable - just finding them using their broken search engine is the trick.

 

Hmmm... Why do you need the adaptors?

 

I used 3/16" for 4mm fittings and 1/4" for 6mm. All the part numbers are in the Small Parts Inc. link.

There are several 4mm to 6mm adapters needed when doing a vacuum hose job. The stock lines in these positions have different sized ends.

 

For the 4 to 6mm adapters, I found brass ones at a local hardware store that worked great. But, the Kynar should work out well - that stuff is VERY resilient with heat.

Dale