Hey all, this is my first post on this site so im hoping that i can get something solved! So i bought my car not knowing the 4x4 didnt work. For awhile now ive been putsing around trying to fix it but finally yesterday i had some time. I replaced the accuator because it was bad as i could tell by the torn boot and loose parts inside it. But also the vacuum line wasnt hooked up to it. So i bought a new accuator, bolted it on and hooked up the vacuum line. Now when i click it into 4hi i can hear something shifting right around where the transfer case is but i still dont have 4x4. What could it be? And i also found a torn vacuum line (or thats what i think it is) that i followed and it ends up belonging to a little black device next to the oil pump. I replaced the torn vacuum line but have no idea where it goes since it was not hooked up in the first place. Anybody have any ideas what that could be for?
Thanks! Markus

 

also when i lock it into four wheel drive, the front drive shaft is solid. Where i can freely turn it in 2hi. Also

 

Search around for 4wd problems, vacuum lines etc.
The front drive shaft not moving or being solid is proper if the vehicle isn't moving. That tells you it's engaged to the transfer case & if it's raised you should be able to rotate the front tires & have the drive shaft turn in neutral.
Vacuum lines are a PITA with these because they have drastic effects when not hooked up. I'd look for any connections that are open, like around the rear of the intake manifold, brake booster & the lines that head to the DS fenderwell.

 

Ok, i found a vacuum line that is unhooked. It comes to a splitter by the brake fluid and fusebox. I just dont know where it is supposed to go. Any ideas?

 

Take a look here; scroll down to the picture of the vacuum lines under the hood. This is from a '96 Sonoma which has the vacuum reservoir ball attached to the hood. Yours has the vacuum reservoir located inside the fender wall (driver's side). It's very difficult to see, but there should be a vacuum line going into it.

An easy way to tell if your 4x4 problem is because of a vacuum leak is that your HVAC vent controls won't work the way they're supposed to. If you can't get air to flow out the correct vents, or airflow varies between vents on its own, that is a sure sign of a vacuum leak. Anythime you have a problem with 4x4 or HVAC, vacuum lines are the first place to look.

 

Alright, thank you. Ofcourse the line thats supposed the be hooked up to the reservoir isnt. Its just hanging there, and my hvac controls are all messed up. Do i have to take off the fender to get the line back on?

 

Don't think so, but the fenderwell liner may have to come off in order to remove/replace the vacuum box. On mine it seems to have a mounting plate behind it INSIDE the fenderwell. I started to remove the bolts but when they were loose I noticed that & said F that! I'll do that a day I have a friend around & more time, just in case.
Is there a vacuum line going to the box in the fenderwell?
You should be able to reach in if you move the brake lines a bit & feel around to make sure the line is leaving the box to the cab for the HVAC as well.

 

If the vacuum line is simply disconnected from the reservoir, there's no reason to remove anything - even though it's really hard to see the nipple that the vacuum line attaches to. There are some pics here that are probably not real helpful, but at least you can see what you're looking for. The reservoir is right behind the brake line apparatus thing. Get a mechanic's mirror and flashlight, maybe you'll be able to see the reservoir and nipple.

 

Ok, lets present mine case:

Front axle doesn't works. I found it in the hard.. hard way...but my trucks came with a Warn winche...

The vacuum houses heading to transfer case, in my 98 blazer, go just a side to the distributor cap. There are three lines: ones thats provide vacuum fron engine; ones thats provide vaccum to actuator and a vent. There is another hose that came from front axle, but it is a vent (which seams similar to vacuum hoses) and is located near front radiator
This image is for prior to 1995 blazer, but the routing is similar
http://www.justanswer.com/uploads/Le...82316_vac1.jpg


Finally, my problem was a miss connected line: the vacuum hose supposed to feed the actuator was connected to the front axle vent hose (WTF???). Now truck works good.

In order to check properly, first remove battery tray and disconnect vaccum line to actuator. check actuator steel cable (the ones that actually connects front shaft to front axle). Some times the cable is rusted by a number of reasons (battery acid leak, salt corrosion). If the cables run smotth... just add a few of WD40 or other penetrating oil and move cable a coulpes of times. If not running, replace cable. Still, in this point, is healthy to check vaccum hoses...

Then, ask some one to "keep an ear" on the actuator disconnected hose. After a brief engine start in 2wd mode, goes below truck, turn the rubber man mode on and disconnect the vacuum hoses from transfer case (single connector . If vacuum from engine if work properly, you will ear a "succking noise" when disconnecting the hoses. If no sucking noise there, bad vaccum hose or bad vacuum switch.
If you found ATF oil there(normally red) ...bad vacuum switch (US$30 i think) and needs to check houses (could have oil there). Also recommended to check transfer case fluid level and remove excess oil (bad transfer casesealing... call your mechanics)
Image of the vaccum switch
http://images2.carpartsdiscount.com/...m_89059420.jpg

If is sucking noise down there, you just try to suck or blow the hoses
There is a view of vaccum hoses conector the transfer case.
http://i11.photobucket.com/albums/a1...uum_switch.jpg
The purge will goes easy
When testing the actuator hose, someone needs to ear the sucking or blowing noise.
Is you feel as a hose blocking or if the person near the hose does ear anything, replace vaccum hose.
If everything is fine and still 4wd doesn't work it could the front axle connection hardware which is worn out, actuator cable disconnected to front axle or the transfer case motor. At this time, if not very handy, ask a mechanics form help. If not, take that tools and start to remove everything!.

Normally, and according to your description, could be a bad actuator cable, bad vacuum switch or worn out/disconnected/colapsed hose.

Finally, there is a thread which explains better that I the whole thing
https://blazerforum.com/forum/2nd-ge...s-40178/page3/

Good luck from Chile!

PS: just remember to check oil level in front axle: mine had 0,5 liter of supposed 1.2 liter!.. And the rear axle had 1.1 liter of supposed 2 liter...

 

Everything is fixed! I just reconnected the unhooked like from the reservoir. After that everything is good.