still foolin with the 4WD

[cardboardpimp420]

I have a 96 S-10 blazer with the 4WD not working. When i push the button to engage it, i hear what sounds like the hubs locking but there is no wheel spinning. Now since my last post (pretty much like this post) i started really tearing into it and seeing if i can find out what the problem is. Now so far I have checked the the vacuum line that goes to the the mechanism that has the cable that attaches to the transfer case. Now, what I have done was unplug that line from the spider before it and just put my finger over the hole. The vacuum feels very weak. I sucked on the line myself that pulls that cable and it seems like it needs a lot of air to do anything to it. Once, it does react though it seems like it needs little to no air to keep it engaged. With the engine off i sucked on the line that returns back to the engine and there seems to be pretty good resistance, and i didn't really hear any leaking. Now I'm completely lost. Is it possible for that mechanism to go out or does it normally need a lot of vacuum to engage it? Or am I completely missing something? Any help would be greatly appreciated.

[MT-2500]

Have you went threw this link?
Is the front axel actuator getting good engine vacuum?
Check for vacuum with a vacuum gauge.
http://www.automotiveforums.com/vbul...d.php?t=572914

[2percent]

My sister had a 1993 blazer that did that and it turned out to be something in her switch itself grounding out. You might give that a try.

[cardboardpimp420]

so do you know off hand what the vacuum should read? also, with the actuator it seems to need a lot of air moving fast to engage it, is that normal?

[MT-2500]

18 or more 20 is better or should read full engine vacuum.
Also check vacuum hoses for transmission fluid.
Vacuum Switch on transfer case should switch vacuum to it when in 4W.