Ok so my 4x4 has stopped working. last year i replaced the front differential and it worked all winter but when i tried it this year, nothing.

when i push the 4x4 button (both high and low) i can hear the motor and feel the transfer case kick in but the front tires do not lock in.

I read in another post that if you pull the wire that is under the battery tray and it locks in then it is the vacuum system. I took a pic of this. I pulled the wire and locked it in with vice grips but the 4x4 still did not engage.

I have also taken pictures of the vacuum lines I have found. the one off the back of the engine goes to the tee. it splits and one runs to the transfer case and the other goes no where and is blocked off at the end.

there is also another vacuum line that is seemingly tied up to the transmission fluid tube that also goes nowhere and is blocked off.

if anyone can help it would be appreciated. Or is anyone knows of a good mechanic in the cleveland area pass that on to me.

 

The one by the transmission tube is supposed to have a filter on the end of it to allow it to vent as this is the vent for the 4wd system as well as the transfer case.

The one over by the brake booster is supposed to hook up to the vacuum reservoir which I believe is still a ball on the 97's and yours appears to be missing. You'll have to get another. On the 98+, it is a rectangular tank mounted inside the front fender behind the ABS pump.


You can find a vacuum diagram in the 4wd Front Axle Clicking When in 2HI - Goes Away when in 4HI/4LO thread.


You will need to replace the faulty vacuum actuator as that is obviously torn. It also appears as though you have a leaking vacuum switch at the transfer case and I am betting that if you were to pull the fill plug (highest plug) on the back of the transfer case, you would be greeted by a few quarts of transmission fluid meaning that the transfer case input seal is faulty and allowing transmission fluid to push past it, over filling the transfer case.


Once you get the input seal replaced and the new switch on the transfer case, you will need to clean out all of the transmission fluid that has migrated into the vacuum system. Hopefully it hasn't made it's way into the HVAC system as that is a mess that can be a major pain to clean up.


Fix all of those issues and you'll likely have it licked.

BTW, excellent post!

 

thanks for the fast reply. I luckily had the vent for the vacuum hose. I also have ordered both the vacuum actuator and vacuum switch. You are correct about the seal I noticed it was bad this summer during oil change and check of levels. It will be replaced in about 10 days. As far as the vacuum resevoir. since mine is missing I have no idea what it looks like. I did find this ebay link 95 97 s 10 Blazer Jimmy Bravada Sonoma Small Vacuum Ball | eBay

is that it? if not can you or someone provide a link to one that i can purchase. thanks again guys for all your help

 

nevermind found the correct ball at rock auto, but where does it mount exactly....does anyone have a picture of where it goes?

 

What is pictured in the eBay link you provided is not the vacuum ball, but the steering rag joint cover so I wouldn't go for that. If you aren't looking for drop in perfect, go for any one of the other vacuum ***** available on eBay. Or you could try to find one from a 95-97 Blazer or S10 in the junkyard. Be careful as the plastic is likely to be brittle from age. I'm not sure what they cost new, but it looks like you have found it.

Here is a picture of where it goes from one of a member gallery:

As you can see, it mounts to the underside of the hood.

 

i found this picture, it appears it just mounts to the hood. is there only one vacuum line that runs to it?

 

Yes there is only one vacuum line to it. It acts as a storage tank for low vacuum situations like acceleration. The 'T' in one of your pictures in your original post also incorporates a check valve. Since all of the vacuum operated accessories (4wd & HVAC) are located after the check valve in the system (or should be), when the engine manifold vacuum level increases, the check valve would close and vacuum would be maintained in the system by the reservoir provided that there isn't a leak in the system.

 

my truck did still have the original ball on it, it just was not pictured. when i went to attach the line i found that the nipple was broken off inside of it so it was a good thing i ordered that as well.

 

ok i got my new actuator in the mail today. I have a couple of questions. how do you take the old one off and 2nd. I can see there is a smaill wire coil going around the opening with a small end going straight thru the opening. Do I need to remove this. It looks as if the end of the wire from the transfer case should lock into this somehow. My current one is not locked in, it just appears "stuck" in the opening.

thanks for any help.