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Vacuum line problem

Hi, all,

Long time lurker, first-day poster.

I've got a 944 with a seemingly storied history. It was maintained really well up until about 1998, when it fell into the hands of a college student who seems to have spent more time redoing her nails in the car than taking any care of it.

The battery is dated 2/2000 but it appears that the previous battery leaked at some point. There is very little corrosion in the compartment... except where the vacuum line runs to the vacuum reservoir right next to the horn. The tube is completely corroded through, and has about a 3" section that is barely staying intact. Obviously it can't hold a vacuum anymore, and the reservoir is completely useless. I've tried to trace the line using the on-fender diagram and a flashlight, but all the vacuum lines and electrical harnesses are bundled together along the firewall.

As near as I can tell, the far end plugs into the brake booster. (Ugh.)

There is no apparent problem with the brakes, but then again I haven't tried panic breaking with the engine off. (One doesn't have the need to try this often, thankfully.) I want to replace the hose, but it appears that Advance Auto Parts doesn't have any tubing this small! It's only 1-2mm O.D.

I'm hesitant to get new tubing from Pelican/AA/etc. because it seems sort of wasteful. (As my credit card company will tell you, I sure don't hesitate to buy trim pieces, electrical parts and suspension components, though!) Does it seem like there would be a problem replacing the tubing with a larger diameter, so long as the ends were tight and properly sealed? I've never really done anything with vacuum lines, but based on my college physics classes it would seem like more volume isn't an issue...

Any input would be great. Thanks, all.
Old 03-21-2005, 12:22 PM
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these vacuum lines seem very similar to the vacuum lines chrysler uses on the 2.2, 2.5 engine.(i have one) i have bought replacement lines with fittings very inexpensive at pep boys for the application. I just worked on a 944 vacuum system and the diameter between the 2 is interchangeable. make sure there are no leaks and they even sell small tie wraps that you can use to secure the connections.
83 944....bye bye
85.5 euro spec 944, 5sp (she's gone....
74 914...hasta LA Vista baby
87 924s....don't let the door hit ya
68 912.......see ya!
Old 03-21-2005, 03:03 PM
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The line that you are refuring to on the brake booster is the check valve, see this thread on Rennlist.

It is not needed for the car to run but your car may run rough. I actually picked up some line of similar diameter that worked fine at lowes but all they had it in was clear.

I have since bought more.

Good luck!

Old 03-21-2005, 05:23 PM
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Holy cow, thanks, that's exactly the tube and my symptoms fit that to a "T". I have a very rough idle (that I had mentally attributed to, among other things, flaky AC and PS belts) that hunts around a bit. I can't wait to replace this hose now. My break is at the other end, but it sure makes sense.

Thanks a lot.
Old 03-21-2005, 05:40 PM
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May or may not be related, but I just got my emissions test and the NOx was really high, within 7-10% of max for my county at both speeds. The car passed, but I immediately started reading and it seems that vacuum leaks can be a major contributor to high NOx emissions, assuming the ignition timing and fuel octane are right.

Definitely need to get this vacuum leak fixed asap.
Old 03-24-2005, 05:28 AM
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