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F150 rear axle vacuum lines

I'm trying to figure out what a couple of vacuum (I think) lines running into the universal joint at the rear axle are for. There are two lines, both connecting to a V shaped connection near the universal joint. One of these lines isn't attached to anything, and I'm trying to figure out where it is supposed to go. There aren't any obvious connections - it doesn't look like those lines are a pair - but the hose is about 18 inches long, so there is quite a bit of ground to cover.

Any board veterans know what this is, and where it is supposed to go?

Reply to
timbrigham
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I hate to waste your time with a guess, but I've seen this on many vehicles. I always thought it was so as the air in the diff warmed, it could vent and not blow up the axle like a balloon.

Reply to
Matt

I don't know for sure either but my guess would be the same. These lines are there so the differential has a vent (it wouldn't bolow up like a balloon, but it could blow out a seal).

Usually they will mount the lines up high, especially on truck and four wheel drive vehicles, so that you won't get water in the axle when you are playing in the puddles.

Steve B.

Reply to
Steve B.

Yup, it's just a vent line. The gear-case needs to be vented somehow, so they run a bit of hose up to someplace fairly high on the body. That way, if you drive through water over the axle, the differential doesn't fill up with muddy water. I hear it happens to the 4x4 guys sometimes.

Peace, Harry

Reply to
Harry Smith

One would likely be the brake line and the loose one the vent line.

Usually the vent has a plastic cap fitting on it and is anchored up under the fender some place. The cap is a one way valve that lets air in and out, but keeps water out. You really don't want water getting into it.

If it has worn off from dragging on the ground, you should get the proper length one and it's cap from the wrecker maybe or you can even just loop the top of it like a cane handle so it will air lock if submersed under water.

Mike

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Reply to
Mike Romain

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