Hello...new to this forum and have already learned alot by searching archives, great site!

The four wheel drive is not engaging on my 1997 Expedition 5.4 liter.

Transfer case works, the problem is the vacuum motor (on the front axle) is not getting vacuum. I am replacing the vacuum elbows at the vacuum motor (diaphram) which were bad. The vacuum motor itself works well when vacuum is manualy applied.

My question is how do you test the solenoids?...I found the terminals supply steady 12 volt flow to both solenoids when the key is on, regardless of the switch position (2, a4wd, 4H). Is this normal? Does the GEM interupt flow to the solenoids to activate them and apply vacuum or should it be the opposite?

What is the procedure to check the function of the solenoids? Or should I suspect the switch?

Thanks,
Kevin

 

I believe +12 is always there and they are controlled by applying and removing ground.

 

Thanks,
I just confirmed the solenoids are functioning correctly by pulling the pink and blue lines at the solenoid with the motor running. Vacuum was as it should be in the various positions of the switch.

I'll pull the entire vacuum lines now, there is no vacuum at the opposite end. My problem must be damaged lines...like so many others who have had axle engaging problems!

 

I hear there are lots of issues with the selector switches on those. Are you seeing the piston move in and out on the diff when you change the selector? If not, trace the vacuum lines back and disconnect at the coupling near the passenger wheel well and put a vacuum gauge on them. They should change when going from 2WD to 4WD. If it looks good, I guess you could check the resistance on the switch. I could ask my buddy if he remembers what they were.

EDITED: *****Sorry, just saw your post! I left to get a few beers and talk with my neighbor while I was typing!

 

I bet it's your shift motor on the transfer case that's bad.

 

Just as I've read in other posts...below the battery tray, the vacuum lines had been desinegrated (about 1" long area) probably due to acid. The rest of the lines are in good shape and cleaned up well. I'll splice it after some shut eye and test her out.

Thanks for the input.

 

Hey...just saw your list of ford stock. I myself have a 1951 8N.

As soon as I fix the 97 Expedition's 4WD, I'm going to retrieve the old tractor from the farm for a wash down and an oil change.

Thanks for the response.

 

Spliced the vacuum lines and all is well now. Thanks for all the information on this site.

It's time to go get muddy!

 

Sorry about getting off topic but you mentioned the Old Pig. When I bought it a few years ago, the poor thing was a rusted heap that would barely run, I tore the engine down, honed the cylinders, put in new pistons and rings. I also put on new brakes, clutch, pressure plate, clutch plate, starter gear, starter, carburetor, and did the 12V conversion with electronic ignition. The thing runs like a top now. I also had to give it a new rattle can paint job that it was just begging for (sorry, I couldn't help it). I sure do enjoy working on it because of the simplicity of it, compared to the vehicles now days. It's amazing all the parts they still make for these things. Here's a couple of photos showing the way the Old Pig looks now.

 

It must be night and day between working on that and an expedition.

 

Boy you're telling me, the electrical system for example consists of about 6 circuits compared to the expy's hundreds. That makes trouble shooting real easy.

 

Now that's cool!

I took my expy down to my farm and drove the 8N up out of the bottoms. Just when I got down by the River the rains came. Boy was I glad the 4WD is fixed. I went through plenty of mud when I retrieved the truck.

We are going to mount some flashing ambers for legal road driving (my house is about 1 mile away by road) and an implement light.

The site I got info from for the restoration is ntractorclub.com. Good folks there. Thanks for posting the pics.

 

I'm glad you got your 4x4 fixed. Here's a couple of sites for parts for the old tractors if you're interested. This first one is where I order most of mine through mainly because they're in Washington state, and I'm in Montana so shipping is real fast. Plus they have a real good selection. http://www.ytmag.com/store/index.htm Here's another one that is more for the 8N. http://ford8n.com/f8shop/index.cgi?ID=X5AJS2 Also there's a bunch of stuff on ebay for these. If you're interested in converting yours to a 12V system, here's a site that has a good write up on how to do it. I highly recommend doing this, it sure makes a big difference, and if you keep all the 6V stuff you can always easily change it back to original if you want. http://home.earthlink.net/~8ntractor/12volt.html

 

Would like to see information on how the EOF system works including the electrical and vacuum aspects. I have vacuum leaks in Hub and solinoid. Replaced solinoid only to discover it was not working. Checked electrical and made the following discoveries. There are three wires. The center wire was 12V. Tried grounding to no avail. But then grounded solinoid wires seperately and made the following measurements. Three wires: Middle Green/pink always hot at 12V

Toward rear: Red; Toward front Gy/Black or maybe white black

Vacuum readings: NO grounding = 0 psi
Rear wire (red) = 7 psi
Front wire (wh/bk) = 3 psi
Combined grounding = 14 psi
I do not know of these are expected outcomes. One video I saw suggested 4 X 4 vacuum about 20 psi, and a lower vacuum for when in 2 wheel drive.

My next steps are to figure out what controls the ground lines and see if I can fix the electrical. I would appreciate any insight and suggestions.

 

Can we assume the vehicle selector switch is not in 2WD and you measured the voltages with the key on or engine running?