Vacuum hoses

Persuasion89 · Post by **Persuasion89** » 08 Apr 2016, 23:29

So ive replaced pretty much all of my vac lines since i found most of them were crumbljng, or already just gone. The thing im curious about is, for lines like the one from im to ptc, that are the hard plastic lines, can j replace them with just rubber or silicone vac line? Also the little elbows, do they perform a function other than just helping to avoid kinks? Can i just put the hose on a nipple and secure it? And also is 1/4" id going to be ok to just run everywhere? 98 volvo s70 glt 2.4l, btw.

Post by **jreed** » 09 Apr 2016, 04:51

cn90 wrote up a great description on replacing the old hard PCV lines with new larger rubber hoses here:

https://www.matthewsvolvosite.com/forums ... hp?t=53448

I replaced many of the crumbling rubber elbows with 6mm ID silicone tubing. I got some thick wall silicone tubing that can be bent without collapsing. It has been holding up well over the past few years.

Post by **erikv11** » 09 Apr 2016, 11:19

- Rubber or silicone is fine, hard plastic is not necessary. From the IM to the PTC, a silicone hose will eventually "sweat" oil so I prefer rubber in that particular application.
- Elbows are not required, and s a rule I get rid of them when I replace vacuum lines (which is pretty much as soon as I get the car!). That's a nice feature of silicone lines, they are very flexible and can make those bends without kinking. But rubber can work great too, just pay attention for kinks.
- Exact diameter is not important as long as you get good seals on the nipples/attachments. I try to match diameter to ensure that seal, along with a clamp or small ziptie.