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While doing some emissions testing on my '96 Mitsubishi Eclipse, I noticed that the vacuum hose from the intake manifold to the brake booster was cracked and decided to replace it. The OEM one has a built in check valve and I cannot find an OEM replacement except the really expensive ones at the dealer. Does anyone know if I can replace it with a normal hose and a normal check valve? If so which check valve should I get and how do I tell which side goes towards the intake?

a picture of your current broken one would really be helpful. and are you sure it is all one peice and the check valve is not removeable?

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    @Bart - Make this an answer, as this is what I'd tell the OP as well.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Dec 2, 2016 at 18:06

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I don't know if it's a very sophisticated kind of hose, but I'd just use some generic hose. You can probably reuse the one-way valve. It's there to maintain the vacuum in the servo when the manifold pressure gets high. Make sure the hose is tightened well with hose clamps, you don't want to suddenly lose your brake boost while you're not expecting it.

The things you need to keep in mind, is that the hose needs to have a rather thick wall (>5mm) to withstand the vacuum, and it has to be heat and fuel resistant. Not all kinds of rubber can withstand fuel, especially the alcohol in E85 gasoline.

Look for hoses for hydraulic oil or something, they are generally quite thick, and would meet the requirements for this job.

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  • Hey Everybody, thanks for all the answers. Here's what I found out. Vacuum hose, esp. for brakes, is very specific, anything else is very dangerous.To help ID it, by standard it is always measured in 32nd's of inch. Parts stores don't carry it. Not sure why, ordered some from Amazon.OEM hose is obsolete, according to Mitsu Dealer.has a small check valve INSIDE the hose, outside it looks ordinary,retrieved the valve,may re-use.The valve/hose didn't malfunction, just old and scary looking. Like me. Exhaustive I-net search:very few options. Ordered chk Valve McMasterCarr: brass, 300psi
    – dave 3515
    Dec 3, 2016 at 13:10
  • @dave3515 Keep in mind that it doesn't have to withstand the slightest pressure per se. It has to withstand vacuum. Although that's still pressure differential, there's a clear difference. The hose will flatten/implode and malfunction if the wallthickness is too small. A thick hose will be much more resistant to implode. The thing is that hoses for pressure are generally thick, and thus also suitable for vacuums. That's why i recommended hydraylic hoses. Good luck.
    – Bart
    Dec 4, 2016 at 14:07

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