# Auto lock front hubs 04' F-350



## ducatirider944 (Feb 25, 2008)

Anyone have a problem with the autolocking front hubs on a super duty? I can't find a vacuum leak, but I'm not getting any vacuum at the hubs when you turn the knob from 2wd to 4wd. I will go on the long search of trying to find the problem, but was hoping that some one here has had this problem and can point me in the right direction, so I don't have to spend a week trying to find the problem. I do know the vacuum system is working on other things, just not the auto locking hubs.


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## B&B (Nov 4, 2006)

Start with checking to see if you have vacuum on the red vacuum line at the hub actuator solenoid on the inner fender with the switch in the 4WD position. If you do, then it's likely the solenoid isn't being activated by the 4WD switch to send the necessary vacuum down to the hubs. Those solenoids go bad quite often.


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## hydro_37 (Sep 10, 2006)

Make sure you have a good vacuum guage when testing.


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## Danscapes (Jan 12, 2008)

I have had the same problem with mine occasionally. Someone told me to push harder on the brake because it runs off the master cylinder pressure. I'm not sure if this works or not, it kind of sounds stupid to me.


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## 01SMOKINSD (Sep 25, 2008)

I had the same problem and found it to be the o rings in the hub itself. I went ahead and replaced the "junk" auto locking hubs with a set of good warn manual locking hubs. Never have to worry wether they are locked in or not. Realatively inexpensive also around $180. Just my .02


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## krazeehorse (Jul 3, 2008)

I had auto hubs fail on an old Chevy and I agree with 01SMOKINSD.


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## redneck farmer (Dec 2, 2006)

Did you recently replace ball joints? If someone replaced the ball joints they might have tried to get awya with not changing the axle seals.


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## Gicon (Oct 1, 2005)

My front hubs have leaked vacuum before. Have them replaced. I think it takes my mechanic 5 mins to take one out and put a brand new one in? It happens....


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