4wd not engaging from cab

[JoeRaven]

A while back I had my ball joints done by a buddy who is a decent mechanic. Ever since then, when I try to switch to 4wd from the interior switch, it will not engage. I have to get out and manually lock the hubs and then i have 4wd. However, when I engage 4wd manually you can feel it surging, or clunking ( I'm not sure how to explain it, maybe grabbing??) when I take a tight corner. I am aware that I'm not supposed to have 4wd engaged on dry pavement but sometimes I forget to change it back right away. I didn't notice this happening in the past when the 4wd was engaging from the cab. I may have just not being paying attention, or maybe it's related to the problem? Any ideas?

[bigcountrysg]

What your basically saying is your vacuum system for the auto locking hubs is not working.

Most likely the seals on the hubs are bad and not allowing the vacuum to build up to engage the hubs.

You will need to replace the hub seals, not hard to do just have to tear apart the hubs.

[NCHornet]

Is your AC coming out of the defrost? This is how you can tell if the vacuum system has a leak. I would check the back of the hubs where the hoses connect. It is a piss poor design, as they simply slide over a nipple, the end gets split and therefore leaks so no vacuum build up. Just cut off 1" or so to get to healthy material and reattach the lines and see if this resolves your problem. if the vacuum pump shuts off it means you don't have a leak. Could also be hub seals as well, but start with the simple stuff.

NCH

[JoeRaven]

Thanks for the suggestions guys.

Bigcountry, now that you mention it, I do recall having an issue a couple of times where the ac was stuck on defrost. After a little while it changed and started to come out of the proper vent. I will check the vacuume lines tomorrow. I am praying that is what it is. I was thinking that the knuckle seals didn't get installed properly. Around here the seals are $75 each.

Is it possible to intall the hubs incorrectly? that would have been my first guess.

[bigcountrysg]

Originally Posted by JoeRaven

Thanks for the suggestions guys.

Bigcountry, now that you mention it, I do recall having an issue a couple of times where the ac was stuck on defrost. After a little while it changed and started to come out of the proper vent. I will check the vacuume lines tomorrow. I am praying that is what it is. I was thinking that the knuckle seals didn't get installed properly. Around here the seals are $75 each.

Is it possible to intall the hubs incorrectly? that would have been my first guess.

No you can not install the hubs incorrectly. They go together one way and come apart one way.

[HunterJ]

I have the same problem as you.

Is there a writeup or something to guide me through the hub repair.

[jasonsthilaire]

Im having the same problem too guys, a writeup on hub teardown would be awesome

[bigcountrysg]

I will look into doing the write up for you all ok.

But I strongly suggest you all pick up a Haynes or Chiltons repair manual. As these books are envaluable to the DIY Mechanic. It has all the info in there on the hubs and stuff.

I am real busy this weekend. But I will see if I can do the write up next weekend ok.

[slowcoupe]

isnt this pretty much it right here including greasing the needlebearings while in there.

Welcome to guzzle's 4x4 Needle Bearing Maintenance Web Page

[JoeRaven]

Here is a write-up I found for replacing the ball joints. You should find what you need, re: the hubs, contained in the write-up. I think the link is on this site somewhere but I don't think it would hurt to post it again.

How to replace your Super Duty Ball Joints - Ford Truck Enthusiasts Forums