how do i know if a vacuum hose has gone bad? also...

JonFreeman938 · Post by **JonFreeman938** » 25 Apr 2011, 16:24

I was checking the vacuum hoses attached to my vacuum tree, and i was just wondering how do i know if they go bad? i tried blowing through them with my mouth and it was pretty tough. one of them i couldnt even blow through. I told someone about this and they also said some of the vacuum hoses only allow air in through one way. is that true? if it is that means i would need to know which ends of the hoses i need to connect to certain spots. If you know anything about these vacuum hoses, your wisdom would be greatly appreciated

Volvos rock3 · Post by **Volvos rock3** » 26 Apr 2011, 04:55

I just started to replace mine. 02 V70XC, none had failed to the point of holes or tears, but they either felt extremely spongy or brittle, rub your thumb on them and bits will fall off. I did the TCV lines and the intercooler lines and what a difference.

Post by **kcodyjr** » 26 Apr 2011, 07:32

If there's anything about them you don't like, consider them bad.

Generally, the authoritative test of "shot" is if they leak, which you determine by squirting carburetor cleaner at them when the engine is running. If the engine picks up at all, the hose is leaking.

JonFreeman938 · Post by **JonFreeman938** » 26 Apr 2011, 14:16

well i couldnt even blow through one of the hoses, but i could blow through all the other ones. does that mean its bad too? also, i got some replacement hoses today too. does it matter what the diameter is of the hoses? it looks like the replacement hose might be just a hair too big.

Post by **jblackburn** » 26 Apr 2011, 16:22

If it's just a hose, yes. If it's a hose with a white check valve at the end of it; that's what it's designed for.

There are 3.5 mm, 4 mm, 6 mm, and 8 mm hoses for the majority of the lines. If you just go to an auto parts store, you will have to find their english-system equivalent.

elchopperfreak · Post by **elchopperfreak** » 26 Apr 2011, 22:39

What "changes" do you notice if the vacuum lines are going?
Is there something under "repairs" as a step by step? I looked for the s70 but could not find it..