hey guys,
Well replaced my u-joint on the passenger side along with the large knuckle seal. to say the least.. a nightmare. Got it all put back together and now my auto 4x4 is not working. dash says it's in 4x4 but it's not engaged. Worked fine before this little adventure. Any ideas? help?
Thanks.
btw it's a 2006 250 superduty gas

 

sounds the knuckle seals are installed wrong and are not sealing correctly. did you replace the big yellow oring?

 

No the oring was fine. And i have the proper tool for setting the seal. Well, we made one from a pc of 2 1/2" pipe and a pipe flange. nothing was bent or twisted. took a few whacks went on good. Thinking maybe a vapor leak.

 

Try AC, if it goes to defrost, you have vacuum leak, most lightly in places you touched. Yellow O-ring shud always be replaced.

 

well, ac seams to be working fine and the heat is coming out where it's supposed to depending on where the **** is placed. I can hear the vacuum opening and closing during each operation. the lines near the knuckle don't seem to be broken anywhere. So a vacuum check is next. If I have to take the hub off again I will most likely need the four bolts and nuts holding it on. They where in pretty bad shape. took all I could muster along with the added help of a pipe on the ratchet to get them off and on. Also one of them was a 18mm instead of a 21 mm like the rest. Another problem arose while putting it all back together though. My tierod end was spinning and the bolt was a nightmare to get back on. Ended up putting a bottle jack under it in order to put it back on.
This turned out to be a way bigger job than expected. Will hook up the new huge compressor we purchased.

 

you understand how the ford auto locking system works?

 

I think so. There is a vacuum line coming in from the pump behind the battery. This line also services the actuator to your hvac controls. It comes into the hub next to the brake line. It sends about 15psi to the auto hub. Which then opens and closes providing the hubs are placed in auto position and there are no internal leaks. Which I think could only be the large seal and the oring. It worked fine before I took it off to change my u-joints. But I never disconnected the line, It was not in the way. I only disconnected the abs sensor.
Am I missing anything? Tough finding accurate info from both ford and online.

 

You get it perfect! the one thing you try, is use your new compressor and only put 15 psi of air though the vacuum line at the hub. then spay is down with soapy water. where the bubbles are is where it is leaking. the same way you might find a nail in a tire.
Did you clean and lube up the locking hub?

 

yes, cleaned the entire inside with light scotchbright pad and pb blaster. Then wiped really good. applied a very thin layer of grease to inside. slid together well. just had to pry on the backside with a prybar to pull it out enough to get that notorious snapring back on. really tight after putting new u-joint on. I'll try that with the compressor, good idea. There is only a inlet for the air not an outlet correct? I didn't locate a second tube.

 

yes, just the one inlet on each side. good luck!