I have read all the posts about hubs not engaging. And yes, when i get the money, manual hubs are in the future but for now I have to deal with what I have. Here is the problem....
- I own a 2000 Diesel Excursion and when I engage the 4x4 and more times then not the hubs will not lock in. It seems that if i cycle the switch i can get it to grab but it won't hold. I tried the method of the a/c vent (i'll tell you how i did it becuase i don't think i did it right). I started the X, turned on the a/c (air is now coming out of the vents, not the defrosters), i then engage the 4x4 ( light comes on) however the air continues to come out of the vents and does not go to the defroster. According to this technique, I do not have a vacume problem. SOO, I went and looked at the hubs. Both seem good. I then took a vacume gauge, went right to the input from the vacume hose to the hub and pumped it up to 10 inHg. It holds but then will slowly trickle down. THen did the same thing to the other side. This time it would not pump up at all. So, i then swapped hubs thinking maybe the hub is bad. The problem stayed on the same side. I then disconnected that hose and capped it. So now the hub that did work is connected the other one is capped off. Hooked up the vacume to the line going out of the relay in the engine compartment to the hubs. The system pumped up fine.
SO I ASK ALL OF YOU SMART GUYS - what the heck is going on? I am not familiar with what is inside that knuckle (don't know the technical term for the part) or hub that keeps the system tight.

 

Have you changed bearings or anything in them lately or ever? You may be in need
of a rebuild with new bearings or at the very least a complete disassembly and a
relube. For some reason maybe it is too hard or people think that it is getting lube
but 4x4 owners never grease their front bearings!! So how did it look in there nice
wet grease or kind of dry and nasty? What type of driving do you normally do 85
mph highway, city or a mix? The old adage use it or lose it most definately applies
to the 4x4 drivetrain at least once a month engage the 4x4 system to keep it all
moving and lubed!!

 

You know, i haven't changed the bearings. However, last year i did completely disassemble the hubs and clean and regrease. When i pulled them out they all still looked very clean and well lubed. I do try to use the 4x4 about every month. They were working just fine about 2 weeks ago. We got a nother good dose of snow and went to use it the other day and that is when i noticed a problem. Will the wheel bearings themselves have to do with the vacume not able to engage the hub? I really am trying to find out what the inside of this bearing housing looks like to figure out if their is a dry rotted seal or something. Either way, if i don't figure it out soon im' going to have to get the warn hubs and just be done with it.