Ford Excursion :: Auto Hubs Won't Disengage?
Aug 7, 2017
After a lot of reading and troubleshooting, I have come to know that it takes vacuum to engage and vacuum to disengage the automatic locking hubs on the Ford F series and Excursion. Most indications is that ~ 15" hg is required to engage and approximately half that much to disengage them. The mechanism that either engages or disengages them acts similarly to a ball point pen. The full amount of vacuum causes the mechanism to travel to it's limit, where the hub is engaged, whereas half the amount of vacuum applied only causes the mechanism to travel to its midpoint, which is where is should be for disengagement.
In my case, I have tested for vacuum leaks, none are present. I have installed new Ford OEM hub assemblies, a new locking hub solenoid and have tested the function of my vacuum pump. It draws about 13.5" hg of vacuum on the system. I do not have any issues with HVAC controls in the cabin of the truck. When installing the new hubs, I ensured that they are unlocked, the inner spline assy spins freely and once installed, the wheel shaft spins freely by hand. When I shift to 4WD on the dash, the hubs engage and all is well.
Problem I am having is when I shift back to 2WD, the hubs remain locked. I can tell as the wheel shafts are not able to be spun freely by hand. I have tried backing the vehicle, etc. No luck. Furthermore, when monitoring vacuum while engaging and disengaging 4WD, I can see that the full vacuum (~13,5") is applied when engaging. What concerns me is that only 3.5 - 4.0" hg is applied when disengaging. This is certainly not enough to operate the mechanism to the point of disengaging the hubs.
I have considered replacing the vacuum pump as I am only getting 13.5" hg of vacuum, however, when I research the replacement part, many have indicated that a new one only draws about that much, so I do not see the value in replacement.
Have any of you dealt with the same or similar problem and if so, what was your resolution?
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And the vacuum pump was replaced.
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I just recently purchased a 2000 Excursion and had some questions up in another thread. After doing some diagnosing....I have a couple of questions about the auto locking hubs. The problem I have is that even with the vacuum line disconnected from the knuckle and no vacuum...the hubs won't unlock in auto/2wd. I confirmed that the knuckle and the hubs will hold vacuum when I hooked my vacuum pump up to it and it held vacuum (the fitting should be clear as I heard the hub making some sounds). I'm getting ready to pull the hubs to clean and re-grease them. My question is that being they are still locked....will it be any harder to pull them off the spindle and after disassembling them/cleaning them.....when I re-install them....will they be unlocked by default after putting them back on the spline as they have been pulled apart and reassembled?
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My Excursion is having an issue with the 4x4 system. The. 4x4 selector switch on dash lights up properly for 4x4, but the auto hubs don't actually engage. The hubs will lock only if I manually lock the hubs. I can hear relay click, so I don't think its electrical. The hubs had new o rings installed when I did front ball joints a few thousand miles ago, and the 4x4 worked fine up until today.
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I've read many posts about ESOF and fault vacuum lines and how that will prevent 4x4 from engaging. I experienced a different problem this past weekend. Here's the situation...
Was about 1.5hr drive up to the mountains. Outside temp when we left the house: 10F. Outside temp when we arrived at destination: 9F. Quite a bit of road grime on the way up from sand, slush, and that magnesium chloride (or whatever they hell they put on the roads in an attempt to keep it from freezing). 4x4 worked fine on the way up. 4x4 light on dash was on, and I KNOW I could not have climbed the snow-covered forest roads without being in 4x4. Also, I could hear and feel the front hubs turning.
On the way home, once I got to where the roads were sufficiently ice free, I turned the dial on the dash back to 2WD. 4x4 light goes out. But I can hear and feel the front hubs are still turning. Toggled the switch back and forth a few times. 4x4 light would come and go with the toggled switch. But the hubs didn't disengage.
When I got back into town (outside temp now about 5), we stopped at a red light and I toggled the switch again. This time, the hubs disengaged. Is this a sign of bad vacuum? Or more an indication of faulty hubs??
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I have a 2005 f350 with the power stroke I went through the hole vacuum system all new hubs, seals, vacuum actuator and fixed it all now I'm having the reverse problems everyone has my hubs are locked all the time as soon as I plug in the vacuum actuator the transfer case is still in 2wd and will switch 4x4 and work and disengage but the hubs are always in unless I unplug the actuator ...
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When I park over night while in 4x4, the next morning my hubs are disengaged and I have to manually lock them. There is an apparent slow/slight leak in the vacuum system. What would be the usual suspect, so I can start at that point?
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I got new auto-locking hubs. The updated ones. As I proceeded to replace them, I pulled out old ones and when driver side came out, there was like 1/2 ounce of water that flowed out from where the auto-locking hub would sit. Strange. I had changed out lines, vacuum pump, vacuum solenoid and reservoir. All new and dry. I blasted both sides down with brake cleaner to clean off old grease, let dry and installed new auto hubs. So far so good. Will test the ESOF feature another time. I was wondering where this water would come from? Other side of wheel hubs are dry.
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My hubs will not lock when put into 4x4. I disconnected all lines from the solenoid to both hubs and tested them for leaks... All good there. I put a gauge on the lines at both hubs one at a time while the other is still connected and get no reading when switched into 4x4. I checked for vacuum right out of the solenoid, and I get 2inHg when switched into 4x.
The vacuum pump kicks on every time I start the truck, even if I just shut it off and re-start right away. There is no delay when switching my ac/heater controls to different settings or vent locations. So I know there is vacuum. How much vacuum I should be getting out of the solenoid to the hubs?
2004 F350 6.0L....
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New to the 4x4 6.0 just bought an 06' King Ranch 130K miles. My other truck is a 95' 7.3 non 4x4 now for sale. So the new to me 06' will not lock the hubs in Auto mode but will in Manual. I have good vacuum down to each wheel hub which is where my question is.
The vac port at either wheel I get 20-30hg however I believe this is only because something is plugged. If I pump up my vac tester to ~25hg right at the wheel port the needle doesn't move, holds vacuum, but does not Auto lock the hub. So I pulled out the Manual/Auto hub by removing the 3 torque screws thinking my vacuum should then go to 0 but it doesn't it stays right at ~25hg.
Before I bought the truck there was some work done to the front end. New ball-joints, Rt tie-rod and perhaps a few other things I haven't ID yet. Could my problem above be an axle seal or something else perhaps installed incorrectly causing the small vac hole going down inside the hub to be covered up or maybe plugged somehow? I believe to replace the ball joints the axle, hub and other parts have to be removed, correct?
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I was using 4x4 High the other day and it was working just fine. Now today, I was at my first parking lot to plow and used the ESOF to shift into 4x4 High and it did not engage with the hubs being in auto mode. The lights on the dash show up indicating that I am, but I am still in 2wd.
If I manually lock the hubs, it engages 4wd high. I tried the same thing using the ESOF to switch over to 4x4 low and it does NOT engage either.
I also noticed that heater blower was switching over to full defrost even though I had it set on the floor setting (manual heat climate *****).
Does this sound like a vacuum leak? I haven't had a chance to test the lines yet. Btw, this is my second work truck and not the one listed in my signature below. It's a 2006 f-350 6.0 xlt.
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I know this is going to sounds lame, my wife can't turn them, they have cover over it that has to be unscrewed to get at 'em. It would be nice to shift in and out "on the fly" as weather condition change.
Is it a difficult change?
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I recently purchased as used 2006 F-150 Lariat 4x4 with 77K miles. I am having an issue with the shift on the fly, I had a vacuum leak that was causing the auto hubs to make noise on occasion but it has never allowed me to shift from 2wd to 4H while moving. I have replaced the IWE solenoid and repaired the vacuum leak but it still will not engage while moving. The light for 4H comes on but the hubs will not engage. The dealer where I purchased the vehicle is not a ford dealership and whey have been trying to solve the problem but to no avail.
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I just heard a dyno operator explain a dip in torque from 1500-2500 rpm as being that the auto box disengages due to excessive torque to prevent damage.
this is for a chipped passat B6 1.8TSI (I know guys in the US dont have this engine) but hardware nonetheless should be similar is there such a feature for the B6 autobox to disengage or pull power in order to protect itseld due to excessive torque?
2ndly, does a dyno even read accurately WOT from 1500-2500 rpm?
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I just put new seals in both front hubs because they were leaking. Now I have good readings when vacuum is applied. When I switch to 4wd the vacuum in hubs goes to about 15 in hg for about 30 seconds or so and my 4wd engages. After the 30 seconds the vacuum is released, I believe that is normal.
Now though my 4wd will not disengage. I get no vacuum pulse when I switch to 2wd, gauge stays at 0 in hg. I'm pretty sure a 5 in hg or so vacuum pulse is required to release hubs....is this correct? Would I be correct that the vacuum solenoid could be the issue or its connection?
Both locking hubs are in great shape and I spliced a vacuum gauge between hub and frame vacuum hose to get my readings. I drove it for 10 min hoping the hubs would disengage but they never did.
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So I noticed the past few days my 09 F250 was clunking in the front end when turning hard even with the hubs in auto so I knew there was an issue in there somewhere. This morning I took the jack and found the passenger side would not release no matter which way the lock was turned. Pulled the locking assembly out and found a couple of the pieces of plastic cage broken (truck has 250k miles) which is to be expected I guess but the locking ring that holds the inner piece that slides over the axle stub was off and hanging next to the c-clip on the axle.
So with the plastic of the cage already being broke and the mileage on the truck it's clear I need a new lock for that side.
Here's my dilemma, I have to deliver a conference room table 200 miles away tomorrow morning that they need for meeting tomorrow afternoon at 3:00pm. I cut the rest of the plastic pieces and took the gears out leaving just the cover with the diaphragm and put it back on the hub. I can't come up with any logical reason why I can't drive the truck this way but just want to bounce it off the experts here before I take off on a 400 mile trip in the morning. The only thing I can come up with is if I were to engage the 4wd the vacuum might suck the auto-lock diaphragm in and pop it but otherwise I can't find any reason to not run it this way, the hub is still sealed up and free-wheeling just like if it were in 2wd anyway.
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I took apart, cleaned and lubed my hubs. My question is: how does the vacuum make the gears work?
Does the vacuum force (suck) the nylon assembly to push the outer gear towards the center of the truck, sliding on the inner gear thus engaging the teeth so that the axle shaft turns the hub?
When the vacuum is gone, does spring pressure pushes the outer gear away from the center of the truck thus disengaging the teeth from the inner gear and allowing the hub to free wheel?
Is this vacuum source constant during 4wd and not present during 2wd or do I not understand how the system works? I have read about a “vacuum pulse” that locks the hubs and another pulse that unlocks the hubs and this confuses me.
BTW, I like the way the Auto lock works. I had a set of Warn Auto Lock hubs on my 78 CJ. They worked on the principle of a set of roller bearings that would lock (pinch) when there was torque coming from the drive shaft. There was no vacuum involved at all. The down side was that when you coasted, the front hubs would be in two wheel drive and so you would not get the engine braking on all 4 wheels. These ESOF seem to have solved this problem.
Oh, I should probably tell you that I just purchased my 04 F250 SuperDuty 4x4 with the 6.0 diesel, just had it a week. It has been 18 years since I owned a 4x4. Before this I owned an 87 F250 2wd with the 6.9 diesel.
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My F350 4x4 won't go into 4 wheel drive unless I get out and take them out of auto and put them in locked position and when I have it in lock mode it seams to work like it's in auto mode, when I put the switch on the dash in 2wd, it seams like it's only driving the back wheels....
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2001 F-250 7.3. The auto lock hubs are not working on the truck lock hubs in and all works fine. First thought is the vacuum system has a leak or something of the sort. Had truck at the shop they are telling me the GEM module controls the vacuum to engage the auto hubs and the signal is not coming from the GEM and it need to be replaced. It was the GEM causing the problem.
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After reading the book, I'm afraid I still don't understand. When the hubs are in AUTO, & the shift on the fly selector is turned to 4X4 high, or 4X4 low, is the truck in 4 wheel drive. What happened to free or lock.
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2008 F350 hubs wont stay locked in when in auto position. everything stays locked while in manual and 4x4 works fine, but in auto the hubs wont stay locked while spinning. I was trying to find the problem when i noticed that one hub stays locked all the time and the other locks and unlocks as it should but it wont stay locked while spinning. My question is do I have two bad hubs or is their a leak that wont let the hub stay locked? Also on the hub that wont unlock is this a leak problem as well or a internal problem?
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