Vacuum lines/tubing...

[Omahaug]

How important is it to get the tubing to the same size as the barbed fitting for vacuum lines? Why don't vacuum lines have clamps like barbed fittings do for other things, is it because vacuum isn't high pressure?

I'm looking to replace vacuum tubing and just want to make sure that when I do I don't inadvertently create a vacuum leak by getting an ID slightly larger than what's on there.

 

[demarpaint]

I make sure they're the same size, the last thing I want is to create a vacuum leak, or compound one.

 

[Johnny2Bad]

Clamps aren't required due to the low pressures involved; in fact these lines never deal with pressure at all; they only deal with atmospheric pressure, which even if there is a total failure or breach, cannot result in a leak, or a lack of pressure.

The major criteria is being robust enough not to collapse under vacuum; completely different from pressure lines that require some clamping force.

 

[Linctex]

Most new rubber vacuum hose that is one size too small will still stretch over a larger nipple.

 

[The_Jeff]

The ID of vacuum line should be close to stock. If you have something like a MAP sensor on the end of several feet of hose (like an 80s chrysler) a restricted line would cause a performance lag.

If you have to stuff it on there, try soapy water for lube.

You also don't want dust and air getting in via a leak.

 

[Omahaug]

Thanks, I've chosen the proper size!

 

[andyd]

Heh heh 80s Grand Wagoneers with a carburetor. Had about 30 feet of vacuum hose in 2 sizes connecting the smog widgets in a series loop. The stuff is cheap. Take a sample to the parts store. Get a little more than you need.

 

[Kira]

HOT-HOT-HOT applications? I use silicone vacuum tubing. 4mm (5/32") is the commonest size.