mbspark

Thanks for the replies. I got home by just plugging up the ends with some pieces of plastic.

Tonight I replaced both actuators and my drivers side hub (it was trashed). I went for a test drive and I still get the grinding.

I came back, and hooked up my vacuum gauge directly to each actuator and it pumps up for a second and goes down. Is this normal?

Then I unplugged the line from the solenoid (with the vacuum lines on the actuators) and pumped up and it held just fine. Just to be sure there wasn't something blocking the line, I unplugged from the actuators, and air just blew threw.

So I'm stumped. The new actuators take air, but don't hold long. The old actuators didn't take any air, you could hear them leak. I would highly doubt I got 2 bad brand new actuators.

My last guess is to replace the solenoid which was replaced back in May. I saw on the forums, I could test it by connecting the 2 vacuum lines, jacking up the truck, running it with the front wheels off and seeing if the CV shafts spin or not.

Truckin

iTrader: (4)

No expert by any means...but when my 14 went... i read where they should hold the vacuum, went it releases is when 4wd engages....perhaps the connection is leaking?
Question for others...can OP put pressure on the lines and bubble test to find the leak?

mbspark

I couldn't help it, I had to go back for more testing. This is probably extremely ignorant, but when bench testing the actuators, do you need to have the vent plugged as well?

I got a good reading off the solenoid, so that's not my problem. I tested my resevoir box and it held.

Then the check valves. Air blows freely through both sides, on both of them.

I'm guessing these are causing the vacuum pressure to not keep up. At least at $5/ea for universals, it's the cheapest thing I've done lately. I'm also planning to drive to ford and test another new actuator with my hand pump.

BadFish523

Did you replace the solenoid? I know yours was the updated version but it still could be bad.

techrep

iTrader: (1)

The IWE solenoid has nothing to do with the wheel ends holding pressure while testing with a vacuum pump.

mbspark

Changed check valves and all seemed ok. Did a drive back from NM to Denver and 45 minutes into the drive the grinding was back.

I unplugged and capped and just ran that way all the way home.

When I got home I ran a vacuum test again, and the line to the IWE's held. I looked at both check valves. One of them whistled when I blew threw the end that was supposed to be closed, but it didn't seem to be freely open.

This IWE system is driving me nuts. I think I'm just going to suffer with MPG and performance loss of leaving them engaged and just plug them back in when I need 4WD.

EBC-150

My truck has 3 check valves in the line...there's a larger one located where the vacuum T's off the brake booster. if you have a lot of rust in the internals of an IWE, the vacuum will suck that up through the system, causing the valves to fail. On my old truck, I had to completely clean the lines, replace all the checks, replace the IWE's, and the solenoid. Then the 4WD worked flawlessly with no 'low engine vacuum' engagement.