What is this?

[getrdone52]

I don't know what it is and was hoping you guys could help. This is in the front passenger side and the female end goes to what looks like the brakes. Could it be a return line or something? I started up the truck and pushed on the brakes all the way about 10 or 15 times and there was nothing coming out. So maybe a vacuum line for the 4x4? It looks like its been unplugged for awhile and I haven't noticed any difference driving. Am I just over reacting? I can post more pics if that makes it easier.

 

[srteach]

For the 1998 truck in your sig:
That connection is a vacuum connection for the PVH hubs. Your 4WD is likely not activating because there is no vacuum to lock the front wheels in.

If you trace the rigid plastic hose that fitting connects to, you will find that it goes to the drivers' side PVH hub.

The factory designed 4WD system uses a short vacuum pulse to lock the hubs to the front axle. 4WD engage / disengage works similar to a retractable pen. Since that plug is disconnected, the system cannot build vacuum to lock / unlock the hubs on either side.

Before connecting it up, I suggest blowing the dirt out of the plastic pipe and the connection side. If you have been in water somewhere, clean and grease the hubs as well.

P.S. The female end goes into the hub, not the brakes.

 

[doorgunner]

He better not force air into anything....removing the lines & cleaing everything out would be a safer idea--that way no junk gets blown into any actuators or orifices...

 

[getrdone52]

Shouldn't my 4x4 lights blinking then? Cuz they're not. And I don't use the vacuum to engage 4x4 I did the manual hub mod. So does it even matter if I plug it back it?