Auto hub maintenance and replacement options

TjMiller

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I just did front brakes on my F350 and noticed my hubs were engaged, haven't used 4 wheel for a few weeks, this is an ESOF system that was set to auto. I flipped the dial back and forth and that disengaged them. Is there any procedure to disengage them when coming out of 4x4 that Im not aware of? Is there any maintenance issues that need addressing on these? Also do a lot of people just switch out for manual lockers on the ESOF systems?
 
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TjMiller

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Any ideas why the hubs would've have been locked? I have been getting a pretty good front end wobble/oscillation from time to time if I hit bumps just right. Any chance this would somehow engage the hubs from bouncing around like that?
 

ckrueg

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Any ideas why the hubs would've have been locked? I have been getting a pretty good front end wobble/oscillation from time to time if I hit bumps just right. Any chance this would somehow engage the hubs from bouncing around like that?
One of my hubs has a vacuum leak and usually it will lock but it won't unlock. I've read that unlocking is usually the first part to go bad with a vacuum leak.

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Radioflyer

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X2 on checking for vacuum leaks. Make sure your vacuum pump is kicking on still too. if there is a gross leak, the pump will eventually wear out from trying to build vacuum.
 

TjMiller

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Before I check want to make sure I know what Im looking for. When 4x4 is switched on the vacuum pump kicks on. I am assuming it shuts off once desired vacuum pressure is reached ? If so, is there a sensor in the pump that tells it when to shut off?
 

dsberman94

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easiest and most hassle free way to fix it is to get a set of manual lock hubs and replace it all and cap the vaccuum line at the frame rail and in the end of the axle with a brass plug. lock them at the first snow fly and unlock in spring when all the snow is gone. otherwise youll have a good time hunting for vaccuum leaks and fighting with crappy hubs
 

Radioflyer

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The sensor or switch is built into the pump. Once it reaches like 15-20 lb/in, it kicks off. If it drops vacuum, it kicks back-on.
 

TjMiller

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easiest and most hassle free way to fix it is to get a set of manual lock hubs and replace it all and cap the vaccuum line at the frame rail and in the end of the axle with a brass plug. lock them at the first snow fly and unlock in spring when all the snow is gone. otherwise youll have a good time hunting for vaccuum leaks and fighting with crappy hubs

I figured on going this route eventually but would like to run the oem hubs until they are shot, which they may or may not be yet. Does anyone know where I can find a parts/service diagram for the vacuum hubs?
 

ckrueg

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I figured on going this route eventually but would like to run the oem hubs until they are shot, which they may or may not be yet. Does anyone know where I can find a parts/service diagram for the vacuum hubs?
You do know the factory hubs are manual as well right? Just turn the knob to lock and then use the dash switch to shift the tcase. Waste of money to swap them imo.

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Zmann

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there is no service procedure for the 05 up ( that I have seen) besides a clean and lube and no parts other than a gasket bolt and oring kit
are sold separate

besides having a manual option
if the auto hub ever fails to unlock you can turn between lock and auto a few time landing on auto it should unlock (may need to drive a few feet) if it was a vacuum issue
 

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TjMiller

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You do know the factory hubs are manual as well right? Just turn the knob to lock and then use the dash switch to shift the tcase. Waste of money to swap them imo.

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I agree, if I don't find any problem with the hubs themselves it would be a waste to replace them. If I had a problem with the vacuum system I could just plug it and switch the stock hubs manually. The vacuum system seems pretty simple so shouldn't be hard to troubleshoot that. My concern was more with the hub internals, if maybe they were known to lock but not unlock when operated in the auto position. I will have to keep an eye and make sure they are free after I disengage 4x4.
 

ckrueg

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If you got a vacuum hand pump with a guage you can check to see if each hub will hold a vacuum and check all the lines. My inner knuckle seal was the source of my vacuum leak

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Bigboytoys

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If you got a vacuum hand pump with a guage you can check to see if each hub will hold a vacuum and check all the lines. My inner knuckle seal was the source of my vacuum leak

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Wrong way around, his is staying locked after using 4x4, not a vacuum leak caused non engagement.
 

pdumont01

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Wrong way around, his is staying locked after using 4x4, not a vacuum leak caused non engagement.
Vacuum is used to disengage when in auto also. Definitely vacuum test the hubs and lines . I believe full vacum 18 inches is applied to hubs when first turned to 4x4 mode. When turned back to 2wd it pulses the vacuum at about 7.5inches to de activate. Could be a slight leak that the lower amount of vacuum can't overcome.
 

Bigboytoys

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??

I haven't ever checked the vacuum on disengagement but mechanically speaking the only thing that disengages the hub gears is a spring pushing them apart, vacuum pulls them together to engage.
 

pdumont01

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Its like one of those buttons you push in that stays in and push again and it pops back out. It just does it with vacuum pulses. The vacuum is only applied momentarily which locks, and then again for a few seconds when switched to 2wd but at a lower rate. The vacuum is not constantly on when engaged.
 
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