4 wheel drive problem

[SynysterHD]

Hey guys! I have an 05' 250 SD FX4, when I turn my switch to the 4 wheel position, the AC turns off and it switches to the defroster... WTF??? It has to be some sort of Vacuum leak, but where do I start? Maybe someone has had this problem and can tell me how to fix it...

[craftkr]

This has been covered in many threads, try the search feature. Not trying to be an ***, but allot of dialog in these threads covering this very issue and some have pics. Mine has the same problem, I simply plugged the vacumm line that goes to the front axle and utilize the manual engagement of hubs.

There are some large O rings on the inside of your front hubs that help a vacuum when you engage your 4x4. It will pulse a then automaticly pull your lock portion of the hub in. These O rings go bad on the inside of the hub and don't allow the vacuum to hold. So when you do this is throws your whole vacuum system off which in turn operates the A/C.

Trace the vacuum line up from your axle. Where it ties into the vacuum system on the passenger side of the engine compartement. You will see the little vacuum pump mounted behind the battery. Just pull the line from your axle where it T's in, and put a cap on this. Your A/C will work fine, but you will need to hop out and manually engage your hubs. Till you can get your O-Rings fixed.

Hope this helps.

[SynysterHD]

Thanks buddy! I'm pretty new to this forum stuff and always forget about the search option. I will check into that issue. Much appreciated. P.S. GO TIGERS!!!!!!!!!!

[Davey~do]

Check the vacuum line line where it fits onto the nipple on the axle. Quite often, you'll find that the rubber hose has just deteriorated allowing the vacuum to leak there. Trim and refit; replace with a new rubber hose, or better yet, replace with a stainless braided hose and not have to worry about it again.

[SynysterHD]

Originally Posted by Davey~do

Check the vacuum line line where it fits onto the nipple on the axle. Quite often, you'll find that the rubber hose has just deteriorated allowing the vacuum to leak there. Trim and refit; replace with a new rubber hose, or better yet, replace with a stainless braided hose and not have to worry about it again.

Hmm! I'll check into that today... Thanks man!

[craftkr]

Originally Posted by Davey~do

Check the vacuum line line where it fits onto the nipple on the axle. Quite often, you'll find that the rubber hose has just deteriorated allowing the vacuum to leak there. Trim and refit; replace with a new rubber hose, or better yet, replace with a stainless braided hose and not have to worry about it again.

That's a good idea, I totally forgot to mention checking the hose down to the axle. And I like the idea of the stainless braided hose...

[SynysterHD]

So today I was under my truck and I noticed what appears to be a seal just hanging loosely on the front axle. This is like this on both sides. Are these seals or are these just dust shields? Maybe this is why I'm having 4WD issues??? I took a pic of it, maybe y'all can help with this one...

[ironlemon]

Every superduty ever produced will do that. They have an updated seal...motorcraft.

[SynysterHD]

So is this why my 4wd isn't working properly?

[ironlemon]

Originally Posted by SynysterHD

So is this why my 4wd isn't working properly?

No you have another problem. Whats dangling on the axle shaft is the dust seal that is supposed to protect the oil seal, which is the half that is still in place.