I replaced main axle seals, yellow O Rings, and hub O Rings when I did my ball joints about a year ago. ESOF has worked fine since then. However, since I recently noticed fluid dripping from the axle shaft, I suppose I damaged one on the axle inner seals when I did the ball joints.
I had a shop replace the inner seals and now neither of my hubs will consistently hold vacuum. The shop says that all of the seals looked new (which they were) so they did not replace any of them. Please don't bother to ask me about the other ESOF system components. The problem IS the hubs not holding vacuum.
Any ideas on what the likely cause off this problem might be? I sure hope its not the main axle seals (the big, expensive, hard to replace ones!)
I disconnected the vac hose behind the wheel and used my Mighty Vac and a 3 ft piece of hose to apply vacuum directly to the hub......is that what you are calling the knuckle inlet?
Which of the three seals are you calling the knuckle seal?
read the above link and check out his 4x4 hub rebuild. If you are 150% its just the hubs not holding vaccum there are more than 2 o rings you want to look at.
Can you explain the baggie, grease, rubber band method?
My biggest fear is that, if the knuckle seal is bad, I will have to pull the axle out and risk damaging the inner seal (again) to install a new knuckle seal. Is that correct?
Are you saying all I need to do is take the hub cap off and seal the exterior end of the hub? If I get good vac then that will say the black HUB seal is bad.....correct? If no vac then its either the yellow o ring or the knuckle seal....correct?
When I did the ball joints a year ago my home made DIY pipe and plate worked fine. I had good vac until a year later when the shop replaced the inner seals.
cap the vacuum ports on the hubs, plug the vaccum lines to the hubs and just turn in the hubs by hand when you want 4x4... so much easier and all you do is walk like 6ft including getting back in
So help me out... the purpose of the selector switch inside of the truck is to electronically lock the hubs via Vacuum and the hub locks themselves are only there as a manual backup?
The switch engages the transfer case motor as well as trigger the vacuum solenoid to the hub's. If the vacuum side of operation is not functional, yes, you can lock the hub's manually and hit the switch to engage the t case and 4x4 will work.
To the OP, whenever those vacuum seals are disturbed, honestly, they should be replaced. They almost always leak when the axle gets pulled out. Even if they were just replaced yesterday
Yes, the switch engages the t case motor.
Often times, when dealing with a 4x4 issue on these trucks, you can separate into 2 categories. A vacuum issue, or an electrical issue. A good tip is if you hit the switch, 4x4 light comes on, you hear the t case motor engage, if no 4x4, you likely have a vacuum issue.
If you hit the switch and no 4x4 light comes on, and you do not hear the t case motor engage, you likely have an electrical issue.
That is not a rule, of course. Just high probability really. It helps to separate the system like this
Yeah atm, i hit the switch, 4x4 light comes on. I hear a click and something else and then RWD only.. so likely a vac issue. I haven't had time to check it but will be do that when I do my front Pinion seal this week. I have read through a number of threads along with countless how to pinion seal videos. I figure i normally learn by doing and if i break something that why there are professional / dealers to clean up the mess.
Honestly, in your case, I usually go straight to the hub's. Pull the vacuum line off at each hub and apply vacuum to the nipple. If they don't hold vacuum, replace the vacuum seals.
They are very common. However, they could have failed and you could still have other issues with the vacuum system. Since that test bypasses everything else in the system. But if they are leaking they need to be replaced regardless
yeah, thats the plan, I have a hand vac pump and was gonna give it a whirl. Figured id start at the hubs and work backwards. Im more concerned with my front pinion pissing fluid atm to bother with the AWD issue but Ill get to it at some point.
I am the OP. I have learned a lot in the last year or so. My hubs have been a PITA since about 2005. The hub seals or the vacuum actuator solenoid are usually the problem. Over the years I have had to replace actuator THREE times. FINALLY, last year I discovered that my hubs themselves (not the seals) were not holding vac. One was obviously cracked. Don't know why the other one would not seal.
Sooooooooo, I finally succumbed and FIXED the problem by plugging off the vacuum line to the hubs from the solenoid and replacing my hubs with manually operated Warns. The OEM vacuum operated were about $300 each with a lousy warranty. The Warns were $286 per pair with LIFE replacement warranty.
This was a good move. Now I KNOW I am in 4WD when I want to be. I used to always wonder and usually found that I was NOT in 4WD. Only thing is I have to engage 4WD inside the cab and THEN get out and manually engage hubs or vice versa.....not much of a problem compared to dealing with and maintaining those POS OEM hubs.
There is also no problem with leaving the hubs locked in and just using the switch to engage 4x4. I have the manual transfer case and hubs and I leave the hubs locked in all winter or anytime I am going somewhere I might need 4x4. You can do the same thing with the esof.
^^ This is absolutely correct, however you will be turning the axle shafts and the differential all of the time, so you will suffer some mileage and possibly a minimal performance loss, not to mention more wear on the u-joints and internals, but if you know you are going to need 4wd, you are concerned that the auto hubs may not function and getting out to lock them in later might be an issue, this is a very good plan.
You won't notice a difference in fuel economy on a diesel truck like you will on a gas truck with having the hubs locked. It may increase wear on the u joints but keep in mind the dodges and jeeps both have full time hubs and the u joints in them last just as long as they to in our trucks.
Your front axle and driveshaft will be spinning. It will cause slightly more wear on the front u joints but not much. I know a guy that leaves his locked in all the time and he still got 100,000 miles out of the factory u joints.
With the hubs locked in, the front wheels become locked to their axle shafts. I'm pretty sure the following components will start turning:
Front axle shaft U-joints.
Front differential ring/pinion gear
Front drive-shaft (connects to transfer case)
Transfer case drive chain
The chain would turn some gearing in the transmission as well, but since its in the neutral position nothing else happens.
I could be wrong... I'm not an expert on the transfer case on these trucks. My only concern would be traveling at highway speeds with the hubs locked. The front diff and possibly some transfer case components could be turning much faster than designed for. Also, these same components are now being 'driven' by the wheels instead of the transmission...
Probably doesn't matter... not sure. There's lots of guys out there that leave the hubs locked. Only dangerous thing would be to engage the transfer case at high speed... I think the manual calls for speeds of less than 55mph to switch from 2WD to 4HI.
This video seems like good reference... even if the red truck is an '80s model Chev with a Ford logo on the front.
My U-Joints are original with 135K miles. I only routinely use 4WD during hunting season. I think I will just lock the hubs at the beginning of the season and unlock afterwards.
Will also lock for one day in mid summer just to exercise / lube stuff.
Or you could fix the problem. Your call. Your decision.
My front u-joints have 176k on them and are in great shape. Granted I bought the truck with 85k on it so it's possible they were changed prior to that, but I seriously doubt it. U-joints are the cheap parts though. Replacing a front chunk or a transfer case is a bit more expensive. These front ends were not necessarily designed for full time use like some of the other designs. You may get good mileage out of them leaving the hubs locked, but why chance it if you don't have to. :twocents:
The transfer case is either a nv271 if manual shift or a nv273 if electric shift, dodge uses the same case in there trucks that have full time hubs so you are not going to damage the t case by leaving the hubs locked. The front axle is a Dana 50 or 60 which again dodge used with full time hubs with no issues.
Ok, you've convinced me, there's no reason to not run your hubs locked all the time. They'll last forever like Dodges do. I can't imagine why Ford thought selectable hubs were a good thing. Why do we even need shiftable transfer case, just make that full time too.
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