So did you also plug the lines at both hubs simultaneously in case they are both leaking? If you only did one at a time you didn't rule that out. Then, if you did that and still had a leak did you plug the PVH solenoid on the hub side, where vacuum leaves the PVH and goes to the hubs? That would prove the PVH good or bad. In my case both hubs were leaking and the solenoid was bad as well. Sometimes the solenoid body actually can crack and leak. The PVH solenoid does not provide a steady vacuum, it provides a "pulsed" vacuum.
Do ESOF vacuum solenoids commonly leak?
After reading a few troubleshooting threads here I took a shot at a quick diagnosing a common HVAC vacuum issue without any specialized equipment.. No dash vent AC. Only defrost vents working.
With the key on the vacuum pump ran continously. I pulled the vacuum outlet line to the resevoir(??) and blocked the pump outlet with my finger. The pump cycled off immediately. I then pulled off the "outlet" hose from the reservoir fitting and blocked same with my finger. The pump again cycled off after what it appears to be enough lag time to reach the desired vacuum pressure. It appears that this portion of the system is working correctly.
I then went to each front hub and disconnected each hose (seperatly) and blocked same with my finger. The pump ran continously on both hubs for considerable time and I could not feel any suction on either side.
I reconnected the wheel hub lines and then disconnected the solenoid vacuum lines (black and red vacuum lines) located on the fender behind the battery. I blocked the red line coming in from the reservoir and again, the pump cycled off after I assume the correct pressure was reached.
So to have AC temporarily, I blocked the red line (at the solenoid connector)and the AC vents now operate normally. If by the rare chance I need 4WD, I will operate the hubs manually.
Also, before I began troubleshooting under the hood, I did notice that when I activated the ESOF switch on the dash, the AC vent dampers would open sending cold air through the dash until I switched back to 2WD and then it would default back to the defrost vents. This is what led me to believe that the solenoid valve might be part of the problem.
What is the likelyhood that my leak is the solenoid unit itself? Thanks.
With the key on the vacuum pump ran continously. I pulled the vacuum outlet line to the resevoir(??) and blocked the pump outlet with my finger. The pump cycled off immediately. I then pulled off the "outlet" hose from the reservoir fitting and blocked same with my finger. The pump again cycled off after what it appears to be enough lag time to reach the desired vacuum pressure. It appears that this portion of the system is working correctly.
I then went to each front hub and disconnected each hose (seperatly) and blocked same with my finger. The pump ran continously on both hubs for considerable time and I could not feel any suction on either side.
I reconnected the wheel hub lines and then disconnected the solenoid vacuum lines (black and red vacuum lines) located on the fender behind the battery. I blocked the red line coming in from the reservoir and again, the pump cycled off after I assume the correct pressure was reached.
So to have AC temporarily, I blocked the red line (at the solenoid connector)and the AC vents now operate normally. If by the rare chance I need 4WD, I will operate the hubs manually.
Also, before I began troubleshooting under the hood, I did notice that when I activated the ESOF switch on the dash, the AC vent dampers would open sending cold air through the dash until I switched back to 2WD and then it would default back to the defrost vents. This is what led me to believe that the solenoid valve might be part of the problem.
What is the likelyhood that my leak is the solenoid unit itself? Thanks.
1 - 2 of 7 Posts
No, I did not plug both hub lines simultaneously. I would not be surprised at all if I found the hub o-rings leaking and a bad solenoid. I replaced the pump a few years ago. The last time the hubs were apart was at about 40K when the crappy factory ball joints failed. The truck just turned over 100K.
That's crazy, my factory ball joints are still good after 142K. My hubs leaked at 130K, or that's when I noticed it. If I recall the PVH solenoid is not very expensive, seems like it was around $70. The hubs I did myself in a half day taking my time and being very careful. A lot of guys like to get rid of the ESOF but I love it, and it's not hard to rebuild when needed.
1 - 2 of 7 Posts
- This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
The Diesel Stop
A forum community dedicated to all Ford Diesel owners and enthusiasts. Come join the discussion about PowerStrokes, performance, modifications, troubleshooting, towing capacity, maintenance, and more!
Full Forum Listing
