Ford Powerstroke Diesel Forum banner

1 - 18 of 18 Posts

·
Registered
Joined
·
34 Posts
Discussion Starter #1
4x4 works when in the locked mode but when in auto if will bot kick in. Just had new tires and front wheel bearing installed on the drivers side and the tires was all around. Just wanted to try and get it fix before i forget and about it when the plow gets on in the winter!! Any help is great and would like to try and do it myself if it is simple? E-mail is best but i will try and check in often!
 

·
Premium Member
Joined
·
11,881 Posts
4x4 works when in the locked mode but when in auto if will bot kick in. Just had new tires and front wheel bearing installed on the drivers side and the tires was all around. Just wanted to try and get it fix before i forget and about it when the plow gets on in the winter!! Any help is great and would like to try and do it myself if it is simple? E-mail is best but i will try and check in often!
Either have a vacuum leak or vacuum solenoid not working. There are 2 or 3 seals on each side that could be causing the problem. The vacuum solenoid is on the passenger side fender behind the battery. Hope this helps a little.
 

·
Premium Member
Joined
·
11,881 Posts
Thats a place to start!!! Thanks
No problem. I would start by checking or replacing the vacuum solenoid. It is a little expensive but it only takes a few minutes to replace. It is about 4-6 hour job to replace all the vacuum seals, and if you do those you might as well replace all the ball joints.
 

·
Registered
Joined
·
55 Posts
No problem. I would start by checking or replacing the vacuum solenoid. It is a little expensive but it only takes a few minutes to replace. It is about 4-6 hour job to replace all the vacuum seals, and if you do those you might as well replace all the ball joints.

If you do not have vacuum, you will be blowing air out of the defrost ONLY.

So unless thats happening I would start by checking the vacuum lines that go to the hubs for wear, cracks, tears, etc...
 

·
Powerstroke Junkie
Joined
·
8,308 Posts
Don't go replacing any solenoid!!! The vast majority of the time the ESOF system fails it is the vacuum connection on the back of the hub. This connection is simply a hose slipped over a nipple, not very secure to say the least. What will happen is the end of the hose will become dry and split, once vacuum is lost the hubs can't operate. Check these first!!! You probably knocked one off, or loose working on the front end, if it is split simply cut those back to where you have good hose and slip back over the nipple. Another place to check would be the pass side footwell there is a line in there that can get kicked loose. Does your ac, and heat only blow out the defrost, this will happen with a loss of vacuum, does the vacuum pump run all the time? It is located on the pass side fender well. Check what I have told you and let me know what you find. If you have no vacuum loss it is probably the seal in the hub itself.

NCH
 

·
Registered
Joined
·
34 Posts
Discussion Starter #8 (Edited)
Ok i was wrong i pushed one of the lines down a little and now all the air comes out the defrost and the pump runs all the time? Is that a dealer only item or can i get it at Advance or o'Reilys? It only runs out the defrost when the 4x4 switch is on? How so you take the pump off, it is on with some type of rubber push in things? Oh and the passenger side foot wall???? Where exactly is that connection.........I found a place where the lines go into a "Y" like thing along the front frame rale?
 

·
PIPE HITTER
Joined
·
1,472 Posts
Don't go replacing any solenoid!!! The vast majority of the time the ESOF system fails it is the vacuum connection on the back of the hub. This connection is simply a hose slipped over a nipple, not very secure to say the least. What will happen is the end of the hose will become dry and split, once vacuum is lost the hubs can't operate. Check these first!!! You probably knocked one off, or loose working on the front end, if it is split simply cut those back to where you have good hose and slip back over the nipple. Another place to check would be the pass side footwell there is a line in there that can get kicked loose. Does your ac, and heat only blow out the defrost, this will happen with a loss of vacuum, does the vacuum pump run all the time? It is located on the pass side fender well. Check what I have told you and let me know what you find. If you have no vacuum loss it is probably the seal in the hub itself.

NCH



I had the same problem, and it was indeed the lines that go the hubs, once you get down there, it's easy to find, and easy to fix....
 

·
Registered
Joined
·
34 Posts
Discussion Starter #10
I just got through checking all the lines that i could find. I turned both directions and check all that i could see and followed them to the junction points. I am guessing it is more then the lines........waiting for help!!!
 

·
Powerstroke Junkie
Joined
·
8,308 Posts
If the pump doesn't stop running it is one of two things 1) a vacuum leak, 98% 2) the solenoid that tells the pump to come on, rarely.

Pull the outake lines from the pump and plug the outake port. This will eliminate all vacuum lines. If the pump runs and shuts off you have a vacuum leak somewhere, if it still doesn't shut off you have one of the rare vacuum solenoids that I have seen go bad. It isn't expensive and easy to replace. Let us know what happens.

NCH
 

·
Registered
Joined
·
34 Posts
Discussion Starter #12
Update....... Talk to a buddy who has a tool to check the vacuum so when he gets home next weekend we will tackle the leak issue and hopefully be able to fix it. He mention something about the hubs have a seal in them that might be leaking??????
Any help on that would be great also! I know that before i bought it the dealer had the hubs taken apart and greased and check so that is starting to make me wonder if they got put back together correctly!
 

·
Powerstroke Junkie
Joined
·
8,308 Posts
Yes there is a seal in them and if you troubleshoot it properly you can rule it out or in. Pull the vacuum lines on each hub and pinch them off with some vice grips or a golf tee etc... Now start the truck, if the vacuum pump runs and shuts off your problem is in the hubs, if it continues to run and run the problem is further back towards the pump. I have already told you how to check the solenoid, so you have all the info to properly troubleshoot the vacuum system. Simple process of elimination. A vacuum gauge will do nothing except tell you how much vacuum you are pulling, it won't tell you anything about the solenoid, for that you need to do what I told you above.
Good Luck

NCH
 

·
Registered
Joined
·
3,035 Posts
The special tool is simply a vacuum pump that any auto parts store will loan you for free. The vacuum check valve is like $20. It was bad on my PSD when I bought it. Is your truck still stuck on defrost?
 

·
Registered
Joined
·
3,035 Posts
Sounds like you have a bad connection *after* your vacuum check valve then. I'd look for a loose hose or cracked hose or something.
 

·
Premium Member
Joined
·
3,578 Posts
These systems are very easy to diagnose with just a simple auto parts store hand held vacuum pump/tester. I got mine for about $20.
You should be able to pull at least 15” on each hub pumping the pump pretty hard by hand. Then if that is okay you can hook the pump to the line going to the hub and watch the gauge when engaging or disengaging 4x4.

When you flip the dash switch the vacuum solenoid/regulator on the fender should supply a pulse of vacuum that last about a minute or so after you flip the switch. There should be 6” when switched one way and 15” when switched the other. The hubs are mechanically latched in or unlatched by the specific pressure of 6” or 15” then they stay in that position and the vacuum turns off until you operate the dash switch again. The thing on the fender is not simply a solenoid but is also a regulator, it not only has to supply vacuum but it has to supply the correct vacuum pressure for the hubs to actuate properly.

With a few minutes and a tester you should be able to find the exact problem and save lots of time and money.

Usually it winds up being the hub seals, there is a seal inside that is both an ID and an OD seal in one seal. Anytime the front hubs are taken off it needs to be replaced, it presses onto the axle than the axle and seal press into the hub. The seals were about $30 each for my truck and I had to build a “special tool” out of a 6x6 block of wood to press mine back together without damaging them.

Here are some pics of my seal install about 5 years ago;
My truck is an early 99 so I assume that a 99.5-03 is similar.





]
 
1 - 18 of 18 Posts
Top